Describing Matter - Mr. Regan's Educational Website ...mrreganhomepage.weebly.com/uploads/4/9/1/7/49171733/...Name Date Class Describing Matter Degradable Plastics A chemical property

Name Date Class

Describing Matter 1a. CLASSIFY The melting point of table salt is 801°C. Is this a

physical or chemical property?

b. DRAW CONCLUSIONS Helium does not usually react with other

substances. Does this mean that helium has no chemical

properties? Explain.

I get it! Now I know that matter is described by its

I need extra help with

7B

What Properties Describe Matter?

Name Date Class

Describing Matter On a separate sheet of paper, explain what matter is and how the physical and chemical properties of matter are alike and different.

7C

Name Date Class

Describing Matter

1. Texture

2. Ability to react with other substances

3. Ability to conduct heat

4. Hardness

5. Lack of ability to rust

6. State

7. Table salt is an example of a(n) substance.

8. The study of matter and how it changes is called physics.

9. Matter is anything that has color and takes up space.

10. A(n) physical property of a substance can only be observed if the substance changes into a different substance.

11. The boiling point of a substance is a(n) chemical property.

7D

Understanding Main Ideas Classify each of the following properties by writing physical or chemical on the line at the left.

Building Vocabulary If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true.

Name Date Class

Describing Matter Degradable Plastics A chemical property is a characteristic of a substance that describes its ability to change into different substances. One way in which substances are changed is to be broken down into simpler substances. Materials that are degradable can be broken down easily in the environment. Most plastics are not degradable, remaining in the environment for a long time. But Today there are two main types of plastics that are degradable: photodegradable (photo- means “light”) and biodegradable (bio- means “life”).

Photodegradable plastics break down into smaller pieces after exposure to a certain amount of sunlight. Biodegradable plastics contain natural substances in addition to the plastic. The most common additive is cornstarch. Cornstarch is made up of sugar that is broken down by microorganisms. When this happens, the plastic breaks down into smaller pieces.

One area in which degradable plastics are being used today involves erosion control. In places where land has been cleared, such as during highway construction, erosion control blankets made with layers of degradable plastic and straw can be placed on the soil. The blanket keeps the soil from being washed away until new plants have a chance to grow. Once the blanket has broken down, the plants’ roots will be able to keep the soil in place.

1. Do you think photodegradable plastic that is buried in a landfill will break down quickly? Explain.

2. Most landfills contain very little air and moisture, which many microorganisms need to survive. How do you think these conditions affect biodegradable plastic buried in a landfill?

3. Why do you think it is important that an erosion control blanket break down after a few weeks or months?

7E

Read the passage and study the diagram below it. Then use a separate sheet of paper to answer the questions that follow.

Name Date Class

Describing Matter Write the letter of the correct answer on the line at the left.

1. The physical property that makes metal pots good for cooking is A flexibility B electrical conductivity C flammability D heat conductivity

3. Which of the following is not true about

a pool of water and a piece of ice? A They have the same composition. B They are in different states of matter. C They have different chemical properties. D They have different physical properties.

2. Which of the following is true about matter? A It is a solid that takes up space. B It has mass and takes up space. C It has mass and is usually a liquid. D It is always a substance.

4. Characteristics used to describe

matter are called A physical properties B chemical properties C both A and B D neither A nor B

Fill in the blank to complete each statement.

5. Solid, liquid, and gas are the three of matter.

6. The metal tungsten is used in incandescent light bulbs because of its property of .

7. is the study of matter and the changes in matter.

8. The ability of iron to rust is a(n) property.

9. A(n) is a single kind of matter that has a specific composition.

10. Another term for the ability to burn is .

7F

Name Date Class

Classifying Matter 1a. REVIEW What holds the hydrogen and oxygen atoms together in a

water molecule?

b. IDENTIFY Table sugar has the chemical formula C12H22O11. What

is the ratio of carbon atoms to oxygen atoms in this compound?

c. DRAW CONCLUSIONS Two formulas for compounds containing

hydrogen and oxygen are H2O and H2O2. Do these formulas

represent the same compound? Explain.

I get it! Now I know that all matter is made up of


I get it! Now I know that the two types of mixtures are


13B

What Is Matter Made Of?

What Are Two Types of Mixtures?

Name Date Class

Classifying Matter On a separate sheet of paper, explain how the following terms are related: element, atom, molecule, chemical bond, compound, mixture, and substance.

13C

Name Date Class

Classifying Matter

1. Describe the basic particle from which all elements are made. 2. How are elements and compounds related? 3. What is the difference between a chemical symbol and a

chemical formula? 4. What are two ways in which mixtures differ from compounds? 5. List four methods that can be used to separate mixtures.

6. atom

7. chemical bond

8. molecule

9. element 10. chemical formula 11. compound 12. mixture

a. shows the elements and ratio of atoms in a compound

b. a group of two or more atoms held together by chemical bonds

c. a substance made of two or more elements chemically combined in a set ratio

d. a substance that cannot be broken down into any other substance

e. two or more substances together in the same place but not chemically combined

f. the basic particle of any element

g. the force of attraction between two atoms

13D

Understanding Main Ideas Answer the following questions on a separate piece of paper.

Building Vocabulary Match each term with its definition by writing the letter of the correct definition in the right column on the line beside the term in the left column.

Name Date Class

Classifying Matter Separating a Mixture Materials

mixture made of sand, sugar, and wood chips plastic dishpan strainer slotted spoon coffee filters measuring cup tap water colander wooden spoons

Procedure

1. Place several cups of the sand, sugar, and wood chip mixture in the plastic dishpan.

2. Carefully add enough water to the dishpan to cover the mixture. 3. Devise a plan to separate the three ingredients in the mixture, using

only the materials listed above. 4. After obtaining your teacher’s approval, try out your plan.

Analyze and Conclude

1. How were you able to separate the wood chips from the mixture? 2. How were you able to separate the sand from the mixture? 3. How could you separate the sugar from the mixture? 4. Did any of the ingredients form a solution with the water? How can

you tell?

13E

Collect the items in the materials list and perform the steps in the procedure. Then answer the questions that follow on a separate piece of paper.

Name Date Class

Classifying Matter Write the letter of the correct answer on the line at the left.

1. A molecule is the smallest part of A an element B a compound C a substance D an atom

3. Compounds are formed as a result of A physical combination B chemical combination C distillation D filtration

2. A mixture of iron and sulfur can be separated by A magnetic attraction B distillation C evaporation D filtration

4. The ratio of hydrogen atoms to sulfur atoms in sulfuric acid, H2SO4 is A 2 to 4 B 1 to 2 C 2 to 1 D 1 to 4

If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true.

5. Salad dressing is an example of a homogeneous mixture.

6. The simplest type of substance is a(n) compound.

7. When elements combine to form compounds, their properties do not change.

8. The chemical symbol for water is H2O.

9. Substances in a mixture keep their own properties.

10. The substances in a heterogeneous mixture can usually be seen and are easily separated.

13F

Name Date Class

Measuring Matter 1a. EXPLAIN Why is mass more useful than weight for measuring

matter?

I get it! Now I know that the SI unit for mass is

and the SI unit for volume is


2a. IDENTIFY Maple syrup will (float/sink) in water because its density is

greater than 1 g/cm3. b. CALCULATE What is the mass of a sample of a substance with a volume

of 120 mL and a density of 0.75 g/mL?

c. Liquid water and ice are the same substance,

H2O. How would you explain why ice floats in water?

I get it! Now I know density is calculated by


19B

CHALLENGE

What Units Are Used to Express Mass and Volume?

How Is Density Determined?

Name Date Class

Measuring Matter On a separate sheet of paper, describe what mass and volume are, in what units they are measured, how they determine density, and why density is important.

19C

Name Date Class

Measuring Matter

1. What is the volume of the solid in the figure? Show your work. Be sure to use correct units of measurement.

2. The solid has a mass of 180 g. What is the density of the solid? Show your work. Be sure to use correct units of measurement.

3. Would the solid have a mass of 180 g on the moon? Would it have the same weight on Earth as on the moon? Explain your answers.

4. The solid sinks to the bottom when placed in a container of water. What does this tell you about its density?

5. Will every solid with the same dimensions have the same density? Explain your answer.

6. International System of Units 7. mass 8. volume 9. density

10. weight

19D

Understanding Main Ideas Use the figure to answer the following questions on a separate sheet of paper.

Building Vocabulary Write a definition for each of these terms on a separate piece of paper.

Name Date Class

Measuring Matter Units of Measurement and Shared Knowledge Communication among scientists is easier when they all use the same standard units of measurement. Imagine trying to communicate information to a civilization on another planet. You do not speak the same language. You may not even share the same knowledge. In 1972, scientists working on the Pioneer 10 spacecraft faced these problems. Because this was the first spacecraft to leave the solar system, scientists attached a small plaque to it, similar to one in the figure below. In case it should ever be found by an extraterrestrial civilization, scientists wanted to communicate some information about where the spacecraft came from.

Unfortunately, an extraterrestrial would probably not understand units such as meters or seconds. What kind of measurements would members of an extraterrestrial civilization understand? Eventually, scientists decided to use a type of energy given off by particles of hydrogen as the basis for a unit of length. A representation of hydrogen particles is labeled A on the plaque. The starburst pattern (labeled B) will help extraterrestrial scientists locate our solar system in the galaxy. The longest horizontal line represents the distance from our sun to the center of the galaxy. The shorter solid lines represent directions and distances from our sun to other stars.

1. Why didn’t scientists use units of measurement on the Pioneer plaque that societies on Earth are familiar with?

2. Do you think it would be easier to communicate information about weight or mass to an extraterrestrial civilization? Explain. (Hint: Consider which of these two measurements is constant.)

3. At the bottom of the Pioneer plaque there is a diagram of our solar system (labeled C). What do you think the small drawing of the Pioneer spacecraft and the arrow coming from the third planet represent?

19E

Read the passage and study the figure below it. Then use a separate sheet of paper to answer the questions that follow.

Name Date Class

Measuring Matter Write the letter of the correct answer on the line at the left.

1. A balloon filled with air does not rise as high as a balloon filled with helium. What does this tell you about the density of helium? A Helium is more dense than air. B Helium is less dense than air. C The two gases have the same density. D When heated, helium becomes more dense.

3. The formula for calculating density is

A Mass × Volume B Mass × Weight

C Mass

Volume

D VolumeMass

2. The amount of matter in an object is a measure of its A volume B density C weight D mass

4. Which of the following statements about the mass of an object is correct? A Mass changes with location. B Mass remains constant. C Mass changes with altitude. D Mass changes with gravity.


5. The SI unit of mass is the cubic meter.

6. One liter is equal to 100 milliliters.

7. An object’s weight is less on the moon than on Earth. On the moon, the object’s mass decreases.

8. An object that floats in water has a density less than 1 g/mL.

9. Four measurable properties of matter are mass, weight, volume, and pressure.

10. The SI unit of volume is the kilogram.

19F

Name Date Class

Changes in Matter 1a. CLASSIFY Mark all the processes that are physical changes.

drying wet clothes cutting snowflakes out of paper lighting a match from a matchbook melting butter for popcorn

b. APPLY CONCEPTS Describe three physical changes that occur in nature.

I get it! Now I know that a substance that undergoes a physical change is


2a. NAME A chemical reaction is another name for a chemical

(combustion/change). b. PREDICT What kind of chemical change do you think occurs

when a banana peel turns brown in the open air? Explain.

c. Assuming no mass escapes, explain why the mass

of a rusted nail is greater than the mass of a nail before it rusted.

I get it! Now I know that when a substance undergoes a chemical change,


29B

What Happens to a Substance in a Physical Change?

What Happens to a Substance in a Chemical Change?

CHALLENGE

Name Date Class

Changes in Matter 3a. IDENTIFY What energy transformation takes place when you exercise?

b. ANSWER How is matter described?

I get it! Now I know that every chemical and physical change includes


29C

How Are Changes in Energy and Matter Related?

Name Date Class

Changes in Matter On a separate sheet of paper, explain how physical and chemical changes are alike and different. Be sure to discuss the role of energy in the changes.

29D

Name Date Class

Changes in Matter

1. Occurs when energy is added or removed.

2. A new substance is produced.

3. A substance changes form, but it remains the same substance.

4. Freezing water is an example.

5. Rusting metal is an example.

6. temperature

7. exothermic change

8. chemical energy

9. endothermic change 10. thermal energy 11. law of conservation of

mass 12. physical change 13. chemical change

a. the energy stored in the chemical bonds between atoms

b. a change in which energy is absorbed

c. a measure of the energy of motion of the particles of matter

d. the total energy of all of the particles in an object

e. the fact that matter is neither created nor destroyed in any physical or chemical change

f. a change in which energy is released

g. a change in matter that produces one or more new substances

h. alters the form or appearance of matter but does not turn any substance in the matter into another substance

29E

Understanding Main Ideas Identify the type of change or changes that apply to each description by writing P for physical change, C for chemical change, and PC for both on the appropriate line.


Name Date Class

Changes in Matter Is It Chemical or Physical? Materials

40 mL skim milk 10 mL vinegar 3 plastic cups coffee filter plastic spoon baking soda 2 pieces of paper

Procedure

1. Pour the skim milk into a plastic cup. Add the vinegar and stir to mix. 2. Pour the mixture through a coffee filter into another cup. 3. Use a plastic spoon to scrape off the material that collects on the

filter. Be careful not to tear the filter. Place this material in a third cup. If this material is too thick, add a small amount of water and stir.

4. Add a pea-sized amount of baking soda to the material in the third cup. Stir to mix.

5. You have made a natural glue. Try gluing two pieces of paper together to see how well it works.

Analyze and Conclude

1. Describe the properties of the ingredients that you used to make the glue.

2. Describe the properties of the glue that you made. 3. Is making glue an example of a chemical change or a physical

change? Explain how you know. 4. Did a change in energy occur with this change in matter? Explain.

29F

Collect the items in the materials list and perform the steps in the procedure. Then answer the questions that follow on a separate piece of paper.

Name Date Class

Changes in Matter Write the letter of the correct answer on the line at the left.

1. Which of the following is not a physical change? A glass breaking B iron rusting C ice melting D sugar dissolving

3. Butter is melted in a pan. Which of the

following is true about the change? A It is a physical change that releases energy. B It is a chemical change that absorbs energy. C It is a physical change that absorbs energy. D It is a chemical change for which there is no

change in energy.

2. Which of the following is not a chemical change? A leaves turning color B fruit ripening C silver tarnishing D food coloring dissolving in water

4. The energy stored in the bonds

between atoms is A chemical energy B thermal energy C electrical energy D endothermic energy


5. A(n) change releases energy.

6. New substances are produced by a(n) change.

7. is related to the energy of motion of the particles of matter.

8. The law of of mass states that in any physical or chemical change, matter is neither created nor destroyed.

9. energy naturally flows from warmer matter to cooler matter.

10. The form or appearance of matter is altered during a(n) change.

29G

Name Date Class

States of Matter 1a. IDENTIFY The two types of solids are

and .

b. EXPLAIN Are the particles in a solid motionless? Explain your answer.

c. DRAW CONCLUSIONS Candle wax gradually loses its shape

as it is heated. What type of solid is candle wax? Explain.

I get it! Now I know that a solid has a definite shape and volume because


2a. NAME A substance that flows is called a . b. DESCRIBE Why is a liquid able to flow?

c. COMPARE AND CONTRAST How do liquids with a high

viscosity differ from liquids with a low viscosity?

I get it! Now I know that a liquid has a definite volume but not a definite shape

because


47B

How Do You Describe a Solid?

How Do You Describe a Liquid?

Name Date Class

States of Matter 3a. DESCRIBE Describe how the motions of gas particles

are related to the pressure exerted by the gas.

b. RELATE CAUSE AND EFFECT Why does pumping more air

into a basketball increase the pressure inside the ball?

I get it! Now I know that a gas has neither a definite shape nor volume

because


47C

How Do You Describe a Gas?

Name Date Class

States of Matter

On a separate sheet of paper, draw a representation of the molecules in a solid, a liquid, and a gas.

47D

Name Date Class

States of Matter

1. What are the general characteristics of a solid?

2. How do crystalline solids differ from amorphous solids?

3. How are liquids described in terms of shape and volume?

4. Explain why a sewing needle can float on the surface of water in

a glass.

5. What determines the shape and volume of a gas inside a container?

6. Rubber and glass, which become softer as they are heated, are examples of crystalline solids.

7. When you see steam, fog, or clouds, you are seeing water in

the liquid state.

8. The volume of a gas is the force of its outward push divided by the area of the walls of the container.

9. A(n) gas has a definite volume but no definite shape.

10. A(n) fluid has a definite shape and volume.

47E

Understanding Main Ideas Answer the following questions in the space provided.


Name Date Class

States of Matter Bottle-Making You learned in this section that glass is an amorphous solid. This property allows it to be molded into shaped such as bottles. Bottles are usually made with an individual section (IS) machine, which is actually a series of automated machines that carry out each step of the bottle-making process. First, very hot, softened glass exits a furnace. Next, the softened glass is cut into lumps, or sections. Each lump of glass moves through the machine to a mold. Air is blown into the mold with great force. This forms the glass inside the mold into a hollow shape called a parison (PAYR uh suhn). Next, the parison is placed in a second mold called the finishing mold. Air is forced into the finishing mold to bring the bottle to its final shape. The entire molding process takes about 11 seconds.

At this point, the bottle is still very hot. After leaving the finishing mold, it travels down a conveyor belt on which it cools and hardens. At the same time, a chemical is usually sprayed on the bottle to give it a hard coating that is resistant to scratches.

1. Why do you think bottles are made from amorphous solids such as plastic and glass? Why aren’t they made from crystalline solids?

2. What must the melting point of the mold be compared to the temperature at which glass gets soft? Why?

3. When the parison is placed on the second mold, it doesn’t yet have the exact shape of a finished bottle. Is the parison’s viscosity low or high? Explain.

4. Glass is sometimes called a supercooled liquid. Why do you think this is so?

47F

Read the passage and study the diagram below it. Then use a separate sheet of paper to answer the questions that follow the diagram.

Name Date Class

States of Matter Fill in the blank to complete each statement.

1. The amount of space that matter fills is its .

2. A state of matter with a definite volume, but no definite shape is a(n) .

3. A(n) will always take the shape and volume of its container.

4. The is a measure of the average speed of the particles in a substance.

5. A(n) has a definite volume but no shape of its own.

6. The of a gas is the force of its outward push divided by the area of the walls of its container.


7. Viscosity is the inward force among the molecules of a liquid.

8. A(n) amorphous solid has a definite melting point.

9. Both gases and liquids are fluids.

10. All solids have a closely packed, fixed arrangement of particles.

47G

Name Date Class

Changes of State 1a. IDENTIFY The change in state from a solid to a liquid is called .

b. COMPARE AND CONTRAST How does what happens to the particles in a

substance during melting differ from what happens during freezing?

I get it! Now I know that melting occurs when the particles in a solid


2a. IDENTIFY The change in state from a liquid to a gas is called . b. APPLY CONCEPTS How does the thermal energy of water vapor change

as the vapor condenses?

c. RELATE CAUSE AND EFFECT Why do clouds form before it rains?

I get it! Now I know vaporization occurs when the particles in a liquid


55B

What Happens to the Particles of a Solid as It Melts?

What Happens to the Particles of a Liquid as It Vaporizes?

Name Date Class

Changes of State 3a. IDENTIFY What is dry ice?

b. PREDICT If you allowed dry ice to stand in a bowl at room

temperature for several hours, what would be left?

c. ANSWER Why does a substance change states?

I get it! Now I know that sublimation occurs when the particles in a solid


55C

What Happens to the Particles of a Solid as it Sublimes?

Name Date Class

Changes of State One winter morning, you wake up to see the outside thermometer below 0°F. You find ice frozen along the sill of the inside of your window. The windowsill was dry when you went to bed. Describe how you think the ice formed overnight.

55D

Name Date Class

Changes of State

1. Both sublimation and occur only on the surface of the substance.

2. The of melting is freezing.

3. When butter is heated it melts, and when that melted butter cools and solidifies the process is called .

4. When a gas turns to a liquid, the energy of the particles .

5. Vaporization is the reverse of .

6. melting

7. freezing

8. condensing

9. vaporizing

10. subliming

a. the change from a liquid to a gas

b. the change from a solid to a liquid

c. the change from a solid to a gas

d. the change from a gas to a liquid

e. the change from a liquid to a solid

55E

Understanding Main Ideas Fill in the blank to complete each statement.


Name Date Class

Changes of State Freeze-Drying Freeze-drying is a method of preserving food. In the first step of this process, the food is frozen, which converts the water in the food to ice. Next, the frozen food is placed into a special chamber. Most of the air in this chamber is pumped out, causing the pressure inside to decrease. At low pressure, sublimation occurs. About 98 percent of the water content of food can be removed with this method.

Freeze-dried foods are commonly eaten by campers and soldiers. One advantage of these foods is that they do not have to be refrigerated. Refrigeration slows the decay of foods by organisms such as bacteria and fungi. Because these organisms cannot reproduce without water, however, freeze-dried foods can be stored at room temperature. Freeze-dried foods are also lightweight. Removing the water from food reduces its mass by about 90 percent. In addition, freeze-dried foods are easy to prepare; they can be restored to their original composition just by adding water.

Food is not the only thing that can be freeze-dried. Florists sometimes freeze-dry flower arrangements to preserve them for up to three years. Scientists freeze-dry cells, tissues, and other samples so that they can be used in research. In addition, books and other papers that have become wet due to flooding can sometimes be saved by freeze-drying.

1. What two changes of state are involved in freeze-drying? 2. Suppose you have 100 kg of fresh strawberries. What would be the

approximate mass of the strawberries after freeze-drying? 3. Why do you think campers and soldiers use freeze-dried food? 4. What is one advantage that freeze-dried foods have over frozen

foods? 5. Is freeze-drying a physical change or a chemical change? Explain.

55F

Read the passage and study the diagram below it. Then use a separate sheet of paper to answer the questions that follow the diagram.

Name Date Class

Lesson Quiz Write the letter of the correct answer on the line at the left.

1. Which of the following describes the process of freezing? A Freezing occurs when the temperature of a

substance drops to 0°C. B Freezing occurs when the particles of a

solid vibrate so fast that they break free. C Freezing occurs when the temperature

drops enough a gas turns into a solid. D Freezing occurs when the particles in a

liquid slow down and take fixed positions.

3. The temperature at which a liquid

turns to a gas is A called the freezing point B called the boiling point C 100°C D the same for an amorphous or a crystalline

solid

2. The process that makes ice cubes shrink as they sit in a freezer is called A sublimation B condensation C freezing D boiling

4. Particles of which of the following have the greatest thermal energy? A a liquid B a crystalline solid C a gas D an amorphous solid


5. Sublimation and boiling both happen at the surface of the substance.

6. Vaporization is the reverse of condensation.

7. The temperature at which a liquid turns to a gas is called the boiling point.

8. Boiling is the reverse of freezing.

9. Water particles in gas coming off of a pan of boiling water are moving slower than the particles of the water in the pan.

10. Evaporation and condensation are both types of vaporization.

55G

Name Date Class

Gas Behavior

I get it! Now I know that when the temperature of a gas at a constant volume

increases,


1a. IDENTIFY The graph of Charles’s law shows that the volume of a gas is

to its Kelvin temperature at constant pressure.

b. PREDICT Suppose the gas in Figure 4 could be cooled to 100 K (−173°C). Predict the volume of the gas at this temperature.

I get it! Now I know that when the temperature of a gas is decreased

at constant pressure,


61B

How Are Pressure and Temperature of a Gas Related?

How Are Volume and Temperature of a Gas Related?

Name Date Class

Gas Behavior 2a. IDENTIFY The graph of Boyle’s law shows that the gas pressure is

to volume at constant temperature. b. READ GRAPHS Use the graph that you made in the Analyzing Data

feature to find the pressure of the gas when its volume is 125 mL.

I get it! Now I know that when the pressure of a gas at a constant temperature is

increased,


61C

How Are Pressure and Volume of a Gas Related?

Name Date Class

Gas Behavior You take a sealed, air-filled balloon, squeeze it and then release it. Next you take the balloon and place it in a refrigerator for half an hour, then remove it. In each case, explain the changes in volume, pressure, and temperature.

61D

Name Date Class

Gas Behavior

1. If the temperature of a gas is constant, when the pressure is increased, the volume decreases.

2. If the air pressure inside an inner tube is constant, when the temperature of the air is increased, the volume decreases.

3. The graph of the relationship between the volume of a gas at constant temperature and its pressure is a(n) line.

4. If the temperature of a gas inside a sealed, rigid container is decreased, its pressure decreases.

5. The graph for Charles’s law shows that the volume of a gas at constant pressure is inversely proportional to its temperature.

6. If a gas at constant pressure inside a cylinder topped by a movable piston is heated, the volume of the gas will increase and push the piston outward.

7. When the graph relating two variables is a straight line passing though the origin, the variables are proportional.

8. According to law, when the pressure of a gas at constant temperature is increased, the volume of the gas decreases.

9. According to law, when the temperature of a gas is increased at constant pressure, its volume increases.

10. When the product of two variables is constant, the variables are proportional to each other.

61E

Understanding Main Ideas If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true.

Building Vocabulary Fill in the blank to complete each statement.

Name Date Class

Gas Behavior Grasping Gas Graphs You have examined the relationship between the temperature and volume of a gas, and between the pressure and volume of a gas. Suppose a scientist wants to determine whether the number of particles of a gas is related to its pressure. Data for this experiment can be collected by increasing the number of gas particles in a container with a constant volume and temperature, and measuring the pressure of the gas. The number of gas particles can be increased by pumping more gas into the container. Sample data from such an experiment are shown by the solid line in Figure 1. The dotted line shows how the resulting graph can be extended.

The relationship between the number of particles of a gas and its volume at a constant temperature can be determined in a similar way. Data for this experiment can be collected by increasing the number of gas particles in a cylinder that has a movable piston and measuring the effect on the volume. The graph in Figure 2 shows sample data from such an experiment.

1. What is the manipulated variable in each graph? What is the responding variable?

2. What is the relationship between the number of gas particles and pressure? Are these two variables directly proportional or do they vary inversely?

3. What is the relationship between the number of gas particles and volume? Are these two variables directly proportional or do they vary inversely?

4. When the number of gas particles in a container with constant volume decreases, how will the pressure of the gas change?

5. When the number of gas particles at constant pressure increases, how will the volume of the gas change?

61F

Read the passage and study the graphs below it. Then use a separate sheet of paper to answer the questions that follow the graphs.

Name Date Class

Gas Behavior Write the letter of the correct answer on the line at the left.

1. At constant temperature, when the volume of a gas is decreased, what happens to its pressure? A It decreases. B It will vary. C It increases. D It remains constant.

3. At constant pressure, how are the

temperature and volume of a gas related? A They are inversely proportional. B They are directly proportional. C They are constant. D They are indirectly proportional.

2. At constant pressure, when the temperature of a gas is decreased, what happens to its volume? A It decreases. B It will vary. C It increases. D It remains constant.

4. If the sun shining through windows

heats the air in a sealed room, what happens to the air pressure in that room? A It decreases. B It will vary. C It increases. D It remains constant.


5. When Martin pushes down on the handle of his bicycle pump, the air pressure within the pump .

6. law describes the relationship between a gas’s volume and pressure when its temperature is constant.

7. law describes the relationship between a gas’s temperature and volume when its pressure is constant.

8. At constant temperature, the pressure and volume of a gas are proportional.

9. At constant volume, when the temperature of a gas decreases, the pressure .

10. When the graph relating two variables is a straight line passing through the origin, the variables are proportional to each other.

61G

Name Date Class

Introduction to Atoms 1a. DEFINE An atom is

b. DESCRIBE Bohr’s model of the atom consisted of a central

surrounded by electrons moving in specific .

c. COMPARE AND CONTRAST How is the cloud model of the atom different

from Bohr’s model?

I get it! Now I know that atomic theory changed with time because


2a. EXPLAIN What is atomic number? How is atomic number used to

distinguish one element from another?

b. APPLY CONCEPTS The atomic number of nitrogen is 7. How many

protons, neutrons, and electrons make up an atom of nitrogen-15?

I get it! Now I know that the modern model of the atom can be described as


79B

How Did Atomic Theory Develop?

How Is the Modern Model of the Atom Described?

Name Date Class

Introduction to Atoms

On a separate sheet of paper, describe the modern model of the atom.

79C

Name Date Class

Introduction to Atoms

1. What three particles are found in an atom? 2. Which two particles are found in an atom’s nucleus? 3. Explain why scientists use models to study atoms. 4. Which two particles in an atom are equal in number? 5. How are elements identified in terms of their atoms? 6. What two particles account for almost all of the mass of an atom?

7. The is the very small, dense center of an atom.

8. The positively charged particle of an atom is called a(n) .

9. A particle with no charge is a(n) .

10. A(n) is the particle of an atom that moves rapidly in the cloudlike region around the nucleus.

11. The tells the number of protons in the nucleus of every atom of an element.

12. Atoms of the same element that have the same number of protons but different numbers of neutrons are called .

13. The sum of protons and neutrons in the nucleus of an atom is the .

14. Scientists will often use a(n) , an object that helps explain ideas about the natural world.

79D

Understanding Main Ideas Answer the following questions on a separate sheet of paper.


Name Date Class

Introduction to Atoms Exactly How Small Is It? Measuring the size of an atom is not easy. For one thing, an atom is very, very tiny. Scientists, however, have developed several ways to estimate the relative sizes of atoms. For elements that exist as two identical molecules bonded together, such as oxygen and hydrogen, scientists can use a technique called X-ray diffraction to estimate the distance between the nuclei. Once scientists do that, they can calculate the atomic radius, which is one-half the distance between the nuclei.

It’s important to remember that the atomic radius is not a measurement of a single atom’s size but only its size relative to other atoms. In other words, scientists know that oxygen atoms are larger than hydrogen atoms, but they don’t know the exact size of any single atom of oxygen. When comparing sizes of atoms, one must be careful to compare sizes based on similar measuring techniques.

The figure below shows the atomic radii of several elements. The atomic radius is given in units of picometers (pm). One picometer is equal to 0.000000000001 meter.

1. What part of an atom determines its size? 2. Why is it difficult to measure the size of an atom? 3. What is the distance between nuclei in a hydrogen molecule (H2)? 4. What would be the distance between nuclei of a bromine

molecule (Br2)? 5. What is the atomic radius of oxygen in meters? 6. Which atoms are relatively larger than oxygen atoms?

79E

Read the passage and study the figure below it. Then use a separate sheet of paper to answer the questions that follow the figure.

Name Date Class

Introduction to Atoms Write the letter of the correct answer on the line at the left.

1. The positively charged particle in an atom’s nucleus is the A electron B neutron C proton D isotope

3. The smallest particle an element can be divided into is the A electron B neutron C isotope D atom

2. An element’s identity can be determined from its A atomic number B number of neutrons C number of isotopes D energy levels

4. The model of the atom that described electrons scattered throughout a ball of positive charge was proposed by A Niels Bohr B Ernest Rutherford C J. J. Thomson D John Dalton


5. An element’s mass number tells the number of protons in its nucleus.

6. Negatively charged particles in an atom are called electrons.

7. The cloud model of the atom describes the location of electrons as specific orbits around the nucleus.

8. Atoms with the same number of protons but different numbers of neutrons are called isomers.

9. The sum of the protons and neutrons in an atom is called the atomic number.

10. An object that helps explain ideas about the natural world is called a model.

79F

Name Date Class

Organizing the Elements 1a. REVIEW In what order did Mendeleev arrange the elements in his

periodic table?

b. PREDICT How could Mendeleev predict the properties of

elements that had not yet been discovered?

I get it! Now I know that when Mendeleev arranged the elements in

order of increasing atomic mass,


2a. COMPARE AND CONTRAST Describe two differences between

Mendeleev’s periodic table and the modern periodic table.

b. INTERPRET TABLES An atom of which element has 47 protons in its

nucleus?

I get it! Now I know that information found on the periodic table for each element

includes


87B

What Did Mendeleev Discover?

What Information Does the Periodic Table Contain?

Name Date Class

Organizing the Elements 3a. NAME The rows in the periodic table are called .

The columns in the periodic table are called .

b. DESCRIBE What do elements in the same group in the periodic table

have in common?

c. PREDICT Use the periodic table to name two elements that you would

expect to have properties very much like those of calcium (Ca).

I get it! Now I know that the periodic table is useful because


87C

How Is the Periodic Table Useful?

Name Date Class

Organizing the Elements On a separate sheet of paper, compare and contrast Mendeleev’s periodic table with the modern periodic table.

87D

Name Date Class

Organizing the Elements Answer the following questions in the spaces provided.

5. In what order did Mendeleev arrange the elements in the periodic table?

6. What do elements in the same column in the periodic table have in common?

7. What can you predict about an element from its position in the periodic table?

8. An element’s is its row in the periodic table.

9. The of an element is the average mass of all isotopes of that element.

10. A(n) is an abbreviation for the name of an element and usually has either one or two letters.

87E

Understanding Main Ideas The diagram below is a square from the periodic table. Label the four facts shown about each element.


1.

2.

3.

4.

Name Date Class

Organizing the Elements Properties of a “Missing” Element To some scientists of the early 1870s, Dmitri Mendeleev’s periodic table of the elements was not very good. They criticized the table because it had gaps in it. Mendeleev, however, believed the gaps would someday be filled by elements that had not yet been discovered. In 1871, he predicted some of the properties of a yet-to-be-discovered element. He called it “ekasilicon.” The “missing” element was not discovered until 1886.

Imagine you are a chemist living in 1880. Study the section of the periodic table shown below as well as the accompanying table of properties. (Scientists in 1880 hadn’t learned what atomic numbers are. They also used “bonding power” to describe the number of chemical bonds an element could form.) *One of Mendeleev’s original “missing elements,” which was discovered in 1875.

1. Which elements would you use to predict the properties of “ekasilicon”? Why?

2. What color would you expect “ekasilicon” to be? 3. How many chemical bonds would you expect “ekasilicon” to form? 4. What atomic mass would you expect “ekasilicon” to have? Why?

87F

Si 28

Ga 70

Sn 119

As 75

“Ekasilicon” ?

Atomic mass

Read the passage and look at the diagram and table below it. Then use a separate sheet of paper to answer the questions that follow the diagram and table.

Some Properties of Selected Elements Element Color Atomic Mass Bonding Power Silicon steel gray 28 4 Gallium* gray-black 70 3

“Ekasilicon” ? ? ?

Arsenic silver to gray-black 75 3 Tin gray-white 119 4

Name Date Class

Organizing the Elements If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true.

1. Mendeleev arranged his periodic table in order of increasing atomic number.

2. The rows in the periodic table are called periods.

3. Moving across the periodic table from left to right, one finds, in order, metals, then gases, then nonmetals.

4. Another name for a period is a family.

5. On the periodic table, elements in the same column have similar properties.


6. An element’s can be predicted from its location on the periodic table.

7. The average mass of all the isotopes of an element is called the .

8. The modern periodic table is arranged in order of increasing .

9. Information found on the periodic table for each element includes its atomic number, , name, and atomic mass.

10. An element with atomic number 10 is located to the of an element with atomic number 9.

87G

Name Date Class

Metals 1a. EXPLAIN What does the term thermal conductivity mean?

b. INFER What property of metals led to the use of plastic or wooden

handles on many metal cooking utensils? Explain

I get it! Now I know that the physical properties of metals include


2a. IDENTIFY Which family of elements in the periodic table contains the

most reactive metals?

b. INFER Period 4 of the periodic table contains the elements potassium, calcium, and copper. Which is the least reactive?

c. APPLY CONCEPTS How is plutonium made?

I get it! Now I know that metals are classified in the periodic table as


95B

What Are the Properties of Metals?

How Are Metals Classified?

Name Date Class

Metals On a separate sheet of paper, identify the properties of metals and describe their position in the periodic table.

95C

Name Date Class

Metals

1. What physical properties are shared by most metals?

2. Sodium (Na) and calcium (Ca) are in different families of metals.

Name the families of metals in which they belong, and describe each family’s characteristics.

3. Would a metal in Group 13 be more or less reactive than a metal in

Group 1? Explain.

4. In what periods are the lanthanides and actinides? Where are they

placed in the periodic table? Why?

5. The reaction of a metal with oxygen to form rust is called .

6. A material that is can be hammered into thin sheets and other shapes.

7. The ability to transmit heat or electricity to other objects is called .

8. A material that is can be drawn into a wire.

9. is the ease and speed with which an element combines with other substances.

95D

Understanding Main Ideas Answer the following questions in the spaces provided. Use a separate sheet of paper if you need more room. Use a periodic table for reference.


Name Date Class

Metals More Properties of Metals You have learned that elements in the same group of the periodic table have similar properties. For example, the metals of Group 1 are so reactive they do not exist uncombined in nature. The Group 2 metals are also quite reactive.

The tables below show the atomic radius and reactivity of most of the metals in Groups 1 and 2. The more reactive a metal is, the more stars appear in the reactivity column. The tables also give the atomic radius of these elements. You might expect the atomic radius of an element to be half its diameter. However, atoms do not have a definite surface, as a ball does. An atom’s electrons are constantly moving around the nucleus in a region of space that has no distinct edge. So, atomic radius is calculated as one half the distance between the nuclei of two identical atoms. The unit of measurement is the picometer (pm). One picometer is equal to 0.000000000001 meter. Group 1

Period Element Atomic Radius (pm)

Reactivity Rating

2 Li 123

3 Na 157

4 K 203

5 Rb 216

6 Cs 235

Group 2

Period Element Atomic Radius (pm)

Reactivity Rating

2 Be 89 3 Mg 136 4 Ca 174 5 Sr 191

6 Ba 198

1. How does the atomic radius change from top to bottom in Groups 1 and 2?

2. How does the atomic radius change from left to right in Groups 1 and 2?

3. How does reactivity change from top to bottom in Group 1? Does the same pattern hold in Group 2?

4. How does reactivity change from left to right in Groups 1 and 2? 5. What seems to be the relationship between atomic radius and the

reactivity of the elements in Group 1 and Group 2? 6. Francium is the Group 1 element of Period 7 and below cesium in

the periodic table. Infer how francium’s atomic radius compares to cesium’s. Do you think francium is more or less reactive than cesium? Explain.

95E

Read the passage and look at the tables below it. Then use a separate sheet of paper to answer the questions that follow the tables.

Name Date Class

Metals Write the letter of the correct answer on the line at the left.

1. If a material can easily be drawn into the shape of a wire, it is A ductile B magnetic C malleable D reactive

3. The metals of Group 1 are commonly called the A transition metals B alkaline earth metals C lanthanides D alkali metals

2. Which of the following is NOT a characteristic of most metals? A brittle B good conductor C ductile D malleable

4. One metal that is a liquid at room temperature is A magnesium B manganese C mercury D sodium


5. Gold, which is in Group 11 on the periodic table, is an example of a(n) metal.

6. The family in the periodic table that contains the most reactive metals is the metals.

7. are devices that move atomic nuclei at extremely high speeds.

8. Elements with atomic numbers above 95 are called elements.

9. Thermal conductivity is the ability of an element to transfer .

10. Reactivity is a(n) property of metals.

95F

Name Date Class

Nonmetals and Metalloids 1a. IDENTIFY What property of nonmetals is the opposite of malleable

and ductile? b. MAKE GENERALIZATIONS What happens to the atoms of most

nonmetals when they react with other elements?

I get it! Now I know that the physical properties of nonmetals include


2a. LIST What are the nonmetals in Group 16 of the periodic table?

b. COMPARE AND CONTRAST How do the chemical properties of the

halogens compare to those of the noble gases?

c. ANSWER How is the periodic table organized?

I get it! Now I know that the families containing nonmetals include


105B

What Are the Properties of Nonmetals?

What Are the Families Containing Nonmetals?

Name Date Class

Nonmetals and Metalloids

On a separate sheet of paper, describe the physical and chemical properties of nonmetals.

105C

Name Date Class

Nonmetals and Metalloids

7. Where in the periodic table are the nonmetals located? Where are the metalloids?

8. A(n) is formed of two atoms.

9. The are a family of very reactive elements.

10. A type of element that has some of the properties of metals and some of nonmetals is called a(n) .

11. The are a family of unreactive elements.

12. A(n) is a type of element whose physical properties are generally opposite to those of metals.

13. A substance that carries electricity under certain circumstances, but not under other circumstances is called a(n) .

105D

Understanding Main Ideas Complete the following table. Use a periodic table for reference.

Element Metal, Metalloid, or Nonmetal Family Name

Arsenic metalloid 1.

Sulfur 2. oxygen family

Tin metal 3.

Neon 4. noble gas

Chlorine nonmetal 5.

Silicon 6. carbon family


Name Date Class

Nonmetals and Metalloids Nonmetals in the Atmosphere On Earth, most nonmetals are found in their uncombined state in the atmosphere. In addition, some nonmetals combine with other nonmetals to form important compounds in the atmosphere. Some of the gases in the atmosphere support life on the planet in one way or another. Others, in great enough concentration, can be dangerous to living things. Composition of Earth’s Atmosphere

1. Based on this table, what do the Group 18 elements have in common?

2. Which substances are combinations of nonmetals? 3. Which nonmetals in the atmosphere and their combinations are

essential to life on Earth? 4. Which are the four most abundant components of the atmosphere?

Taken together, about what percent of the atmosphere do those four components make up?

105E

Read the passage and look at the table below it. Then use a separate sheet of paper to answer the questions that follow the table. You may refer to the periodic table.

Component Percent in Air at Sea Level Relationship to Living Things

Nitrogen (N2) 76.08 Used by bacteria to produce substances plants can absorb as nutrients; part of all proteins

Oxygen (O2) 20.95 Required for respiration, a process in living things that releases energy

Water (H2O) 1.0 (avg.) Essential to life as we know it

Argon (Ar) 0.93 None known

Carbon dioxide (CO2)

0.032 Needed by plants to produce their own food through photosynthesis

Neon (Ne) 0.001 None known

Helium (He) 0.0005 None known

Nitrous Oxide (N2O) 0.00003 Commonly used as a dental anesthetic but has no

effect in concentrations found in the air

Carbon monoxide (CO) 0.00001 Poisonous gas produced in part by the burning of

fossil fuels

Name Date Class

Nonmetals and Metalloids Write the letter of the correct answer on the line at the left.

1. Which of the following is NOT a property of most nonmetals? A found on the right side of the

periodic table B solids tend to be dull and brittle C excellent electric conductivity D many are gases at room temperature

3. Two of the same atoms bonded

together is called a(n) A isotope B diatomic molecule C binary atom D semiconductor

2. The only nonmetal in Group 14 is A carbon B oxygen C nitrogen D fluorine

4. The highly reactive nonmetals of Group 17 are called the A noble gases B metalloids C halogens D actinides


5. Atoms of nonmetals usually lose electrons when they combine with other atoms.

6. When two or more atoms bond by sharing electrons, they form a molecule.

7. The elements that have some properties of metals and some properties of nonmetals are called halogens.

8. Helium has chemical properties so different from those of the other elements that it cannot be placed in any group.

9. Substances that can carry electric current under some conditions but not under others are called semiconductors.

10. The Group 15 element oxygen is used to make compounds known as fertilizers.

105F

Name Date Class

Radioactive Elements 1a. DEFINE The spontaneous emission of radiation by an unstable atomic

nucleus is called b. APPLY CONCEPTS What caused the fogging of the photographic plates

that Becquerel observed in 1896?

I get it! Now I know that during radioactive decay


2a. IDENTIFY What is the name of the particle produced by radioactive

decay that consists of 2 protons and 2 neutrons?

b. COMPARE AND CONTRAST Rank the three major types of nuclear radiation from 1 (most penetrating) to 3 (least penetrating). Alpha Beta Gamma

c. PREDICT What is the identity and mass number of the nucleus formed

during the beta decay of magnesium-28?

I get it! Now I know that the three major forms of radiation produced during radioactive

decay are


113B

What Does Radioactive Decay Produce?

What Happens to an Atom During Radioactive Decay?

Name Date Class

Radioactive Elements 3a. EXPLAIN Why is half-life useful to an archaeologist?

b. RELATE CAUSE AND EFFECT Why are radioactive isotopes that emit

gamma rays useful for treating some forms of cancer?

I get it! Now I know that four uses for radioactive isotopes are


113C

How Are Radioactive Isotopes Useful?

Name Date Class

Radioactive Elements

On a separate sheet of paper, define radioactive decay, describe its products, and summarize its uses.

113D

Name Date Class


4. Scientists use the amount of radioactive isotopes found in rocks and fossils to calculate their ages. This process is called .

5. A(n) consists of two protons and two neutrons and is positively charged.

6. A(n) involves the particles found in the nucleus of an atom. It changes one element into another element.

7. consists of high-energy waves and always accompanies alpha and beta decay.

8. The spontaneous emission of radiation by an unstable atomic nucleus is called .

9. A(n) can be used by doctors and by industry to diagnose problems.

10. A(n) is a fast-moving electron given off by a nucleus during radioactive decay.

11. Half of the radioactive atoms in a sample of sodium-24 will decay in 15 hours. Fifteen hours is the of sodium-24.

113E

1. 2. 3.

Understanding Main Ideas Look at the diagrams below. Label each diagram with the type of radioactive decay it illustrates.


Name Date Class


Radon Gas Radon is a radioactive element that is formed from the radioactive decay of uranium-238. Radon-222 is the most common isotope of this element. Its half-life is 3.8 days. Radon is a colorless, odorless, tasteless gas.

Because uranium-238 is fairly rare, so is radon gas. Uranium-238 is found under Earth’s surface in some types of rocks. When radon is formed, it tends to rise up to the surface. Because radon is much more dense than air, it tends to stay very close to the ground. As a result, it sometimes builds up in the lower levels of houses, especially in underground areas such as basements.

Being exposed to high levels of radon gas over a period of time can increase a person’s chances of developing lung cancer. The level of radon gas in a home can be measured with a testing kit. If radon is found, there are several methods of preventing more of it from entering a house. One method is called soil suction. Soil suction involves pulling the radon gas from the soil below the house and into a pipe. The pipe releases the gas away from the house. Other methods involve increasing the movement of fresh air through the house or sealing cracks through which radon gas can enter.

1. If there is almost no uranium in the area where someone lives, should that person be concerned about radon gas in his or her home? Why or why not?

2. Should someone who lives on the sixth floor of an apartment building be concerned about radon in his or her apartment? Why or why not?

3. Do you think radon would be more of a health hazard if it were a solid instead of a gas? Explain.

4. The diagram below shows how uranium-238 decays to radon-222. For each step in this process, fill in the blank to indicate whether an alpha particle or a beta particle is produced. The first step has been done for you.

113F

Read the passage. Then use a separate sheet of paper to answer the questions that follow.

b. c. d.

e.

a. uranium-238 thorium-234

alpha particle

protactinium-234

radium-226

radon-222

thorium-230 uranium-234

Name Date Class

Radioactive Elements Write the letter of the correct answer on the line at the left.

1. Radioactive isotopes that can be followed through the steps of a chemical reaction or industrial process are called A transformers B tracers C gamma rays D reactants

3. Alpha and beta decay are almost

always accompanied by A gamma radiation B an increase in atomic number C a decrease in atomic number D a catalyst

2. Which statement is NOT true of radioactive decay? A It involves the nucleus of an atom. B It involves radioactive isotopes. C The identity of the atom remains the same. D Fast moving particles and energy are

released.

4. In relation to the original atom, the

atom that results from beta decay has an atomic number that is A 1 less B 1 more C 2 less D the same


5. Uranium was the radioactive element studied by Becquerel and the Curies.

6. The most penetrating type of nuclear radiation is the alpha particle.

7. The half-life of cobalt-60 is 5.26 years. After 10.52 years, 5 grams of a 20-gram sample will remain.

8. During radioactive decay, the identity of an atom remains the same.

9. Alpha particles are fast-moving electrons given off during radioactive decay.

10. Chemical reactions involve the protons and neutrons in the nucleus of an atom.

113G

Name Date Class

Atoms, Bonding, and the Periodic Table 1a. DEFINE What are valence electrons?

b. EXPLAIN Why do the properties of elements change in

a regular way across a period?

c. RELATE CAUSE AND EFFECT Explain the reactivity of the noble gases in

terms of valence electrons.

I get it! Now I know that the chemical properties of an element are determined

by


129B

What Determines an Element’s Chemistry?

Name Date Class

Atoms, Bonding, and the Periodic Table On a separate sheet of paper, use the periodic table to create electron dot diagrams for barium (Ba), carbon (C), cesium (Cs), iodine (I), krypton (Kr), phosphorous (P), and strontium (Sr).

129C

Name Date Class

Atoms, Bonding, and the Periodic Table

1. How many protons does a nitrogen atom have?

2. How many valence electrons does a nitrogen atom have?

3. Is nitrogen reactive or stable?

4. Neon (Ne), which has an atomic number of 10 is in Group 18 in the periodic table. To which group does nitrogen belong?

5. The element directly below nitrogen in the periodic table is phosphorous (P). How many valence electrons does phosphorous have?

6. Will the properties of nitrogen be more similar to the properties of neon or the properties

of phosphorous? Explain.

7. An element’s reactivity is determined by the number of protons found in an atom of the element.

8. The force of attraction that holds two atoms together is called a chemical bond.

9. In a(n) periodic table, dots around an element’s symbol indicate the number of valence electrons in an atom.

129D

Understanding Main Ideas Look at the diagram below. Then answer the following questions in the space provided.


Name Date Class

Atoms, Bonding, and the Periodic Table The Rockets’ Red Glare The basic fireworks unit is called a shell, and it is packed with chemicals that produce light, smoke, and noise when they burn. The effects depend on which chemicals are packed into the shell and how they are arranged.

A simple shell is shown at the right. When the gunpowder is at the bottom of the shell is lit, it explodes and lifts the shell into the air. By the time the shell has reached the high point of its path, a second fuse ignites the other chemicals. Some shells explode all at once. Others are made of smaller shells that burst apart and explode separately. Time delays can be used to make a shell explode in stages.

The table below lists some chemicals and the effects they produce.

1. To which groups of the periodic table do the majority of the elements listed in the table above belong? Why do you think elements in these groups are used in making fireworks?

2. Which group of elements could you not use in making fireworks? Explain your answer.

3. Why would you want to have two or more separate fuses in a rocket? 4. Solutions of magnesium, barium, and strontium are clear and

colorless. Predict what might happen if a drop of each solution was held in the flame of a lab burner.

129E

Read the passage, look at the diagram, and study the table. Then use a separate sheet of paper to answer the questions that follow.

Element Effect strontium or lithium red color barium green color copper blue color sodium yellow color magnesium or aluminum white color potassium or sodium whistling sound potassium and sulfur white smoke

Name Date Class

Atoms, Bonding, and the Periodic Table If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true.

1. An atom’s valence electrons are those electrons that have the highest energy.

2. Atoms tend to be stable and nonreactive if they have six valence electrons.

3. In the periodic table, the number of valence electrons in each element decreases from left to right across each period.

4. The reactivity of a metal depends on how easily it loses its valence electrons.

5. Within each period in the periodic table, elements have similar properties because they have the same number of valence electrons.


6. The number of in the atom of an element determines its chemical properties.

7. The columns in the periodic table are called .

8. A(n) shows the number of valence electrons in an atom in pictorial fashion.

9. The attractive force that holds two atoms together is called a(n) .

10. Because it can either lose or share electrons when it combines with other elements, each has some of the properties of metals and some of the properties of nonmetals.

129F

Name Date Class

Ionic Bonds 1a. REVIEW An atom that loses a valence electron becomes a (positive/

negative) ion. An atom that gains a valence electron becomes a (positive/negative) ion.

b. APPLY CONCEPTS Write the symbols for the ions that form when potassium and iodine react to form the ionic compound potassium iodide.

c. RELATE CAUSE AND EFFECT Why is potassium iodide electrically neutral?

I get it! Now I know ions form when


2a. EXPLAIN The formula for sodium sulfide is Na2S. Explain what this

formula means.

b. APPLY CONCEPTS Write the formula for calcium chloride. Explain how

you determined this formula.

I get it! Now I know that to write the formula for an ionic compound,


137B

How Do Ions Form?

How Are the Formulas and Names of Ionic Compounds Written?

Name Date Class

Ionic Bonds 3a. REVIEW Ionic bonds are strong enough to cause all ionic compounds

to be at room temperature.

b. RELATE CAUSE AND EFFECT Solid table salt does not conduct electric

current. How does dissolving salt in water allow electric current to

flow?

I get it! Now I know that properties of ionic compounds include


137C

What Are Properties of Ionic Compounds?

Name Date Class

Ionic Bonds A fluorine (F) ion has a charge of 1–. An aluminum (Al) ion has a charge of 3+. On a separate sheet of paper, explain how fluorine and aluminum would exchange valence electrons to form an ionic compound. Then write the compound’s chemical formula and name the compound.

137D

Name Date Class

Ionic Bonds

1. Negative ions form when atoms valence electrons.

2. In the formation of an ionic compound, a metal atom is most likely to valence electrons.

3. Ionic compounds form because charges attract.

Answer the following questions in the spaces provided. You may use a periodic table.

4. A potassium ion has a charge of 1+. A sulfide ion has a charge of 2−. What is the chemical formula for potassium sulfide?

5. Name the following compound: MgO.

6. ion

7. polyatomic ion

8. ionic bond

9. ionic compound

10. chemical formula

137E

Understanding Main Ideas Fill in the blank to complete each statement.

Building Vocabulary Write a definition for each of these terms on a separate piece of paper.

Name Date Class

Ionic Bonds

Pulling Away Electrons You know that the metals in Group 1 and 2 are quite reactive. They combine easily with certain other elements to form compounds. Atoms from Group 1 react by losing one electron; atoms from Group 2 lose two electrons. It takes energy to remove an electron from an atom. Some atoms hold their electrons tighter than other atoms do. Also, an individual atom holds some of its electrons tighter than other electrons.

The size of an atom’s radius affects how tightly it holds its electrons. The larger the radius of an atom, the farther away from the nucleus some of its electrons are. The electron held the least tightly is easiest to remove. To remove yet another electron requires more energy than was needed to remove the first. The figure below compares the atomic radii of the elements in Groups 1 and 2. The number underneath each element represents the atomic radius measured in picometers (pm).

1. What do you notice about atomic radius as you look down a group? As you look across a period from Group 1 to Group 2?

2. Which element would you expect to be the most reactive in Group 1? In Group 2? Explain your answer.

3. Within each period, which element of the two groups would you expect to be more reactive? Explain your answer.

4. Across the periodic table, atomic radius continues to decrease through Group 17. How does this fact help explain why the metals in Groups 3 through 13 are less reactive than the metals in Group 1 and 2?

137F

Read the passage and look at the diagram to its right. Then use a separate sheet of paper to answer the questions that follow.

Name Date Class

Ionic Bonds Write the letter of the correct answer on the line at the left.

1. Ionic bonds form between two ions that have A ionic compounds B negative charges C positive charges D opposite charges

3. Which is most likely to form a negative

ion? A an element from Group 17 B a metal C an element from Group 1 D an element with atoms that have eight

valence electrons

2. Ions that are made of more than one atom are called A ionic compounds B crystals C polyatomic atoms D ionic bonds

4. Which of the following is the

correct name for MgCl2? A magnesium chlorine B magnesium dichlorine C magnesium chloride D magnesium dichloride


5. A(n) is an atom or group of atoms that has an electric charge.

6. The attraction between oppositely charged ions is called a(n) .

7. When an atom loses a valence electron, it becomes a(n) ion.

8. In order to have a stable arrangement of 8 valence electrons, metal atoms are likely to electrons.

9. In an ionic compound, the total positive charge of all the positive ions the total negative charge of all the negative ions.

10. Because the force of attraction between the positive and negative ions is so strong, ionic compounds have melting points.

137G

Name Date Class

Covalent Bonds

I get it! Now I know that the atoms in a covalent bond are held together by


I get it! Now I know that properties of molecular compounds include


145B

How Are Atoms Held Together in a Covalent Bond?

What Are Properties of Molecular Compounds?

Name Date Class

Covalent Bonds 1a. REVIEW What type of bonds are formed when atoms share electrons

unequally?

b. PREDICT Would carbon dioxide or water have a higher boiling point?

Explain.

c. ANSWER How can bonding determine the properties of a substance?

I get it! Now I know that some atoms in covalent bonds become slightly negative or slightly

positive when


145C

How Do Bonded Atoms Become Partially Charged?

Name Date Class

Covalent Bonds

On a separate sheet of paper, compare and contrast carbon dioxide and water. Be sure to fully describe the types of bonds involved, and compare and contrast the properties of the compounds.

145D

Name Date Class

Covalent Bonds

1. Circle all of the covalent bonds in the electron dot diagrams. 2. Which bond(s) shown are double bonds?

3. Which bond(s) shown are triple bonds?

4. Which molecule(s) shown have polar bonds?

5. Compare and contrast O2 and F2.

6. molecule

7. double bond

8. nonpolar bond

9. polar bond

10. covalent bond

a. the chemical bond formed when two atoms share electrons

b. a neutral group of atoms joined by covalent bonds

c. a bond in which electrons are shared unequally

d. a bond in which electrons are shared equally

e. a bond in which four electrons are shared

145E

Understanding Main Ideas Answer the following questions in the spaces provided. Use the diagram at right to answer questions 1–5.


Name Date Class

Covalent Bonds

Oil Spills Each year over 907,000 metric tons of crude oil are spilled in Earth’s oceans. This is enough oil to fill 100 school gymnasiums! It is important to clean up crude oil as soon after a spill as possible, because spilled crude oil has negative effects on the environment. Oil on ocean surfaces is harmful to ocean life because it blocks sunlight and reduces the level of dissolved oxygen in the water. In addition, many birds and fish die from contact with crude oil because the oil damages feathers and gills.

Two methods used to clean up oils spills are

1. A floating barrier is placed around the spill to keep it from spreading. Because oil floats on water, the oil can be skimmed off the top of the water. Skimming the top of the water using a net with extremely small holes allows the water to escape but not the oil.

2. Chemicals that act like detergents are sprayed onto the surface of the spill. These chemicals break up the oil into tiny droplets. The small particles of oil spread over a large area have less effect on marine life than larger particles.

Both of these methods work because of the chemical properties of oil molecules. Oil molecules are nonpolar, so they will not mix with polar water molecules. Detergents are long molecules that have a polar end and a nonpolar end, like the molecule shown in Figure 1. The polar end of the detergent attracts water molecules, and the nonpolar end attracts oil molecules. Figure 2 shows how detergent molecules cause the formation of droplets of water, detergent, and oil molecules.

1. Explain how the nonpolar character of oil molecules helps when removing oil from water using nets and floats barriers.

2. The long “tail” on a detergent molecule is made up mostly of carbon atoms bonded to other carbon atoms. Why would you expect the tail to be nonpolar?

3. How does detergent sprayed on an oil spill break up the spill?

145F

Read the passage and look at the diagrams next to it. Then use a separate sheet of paper to answer the questions that follow the passage.

Name Date Class

Covalent Bonds Write the letter of the correct answer on the line at the left.

1. In an electron dot diagram, two pairs of shared electrons represents a A single bond B double bond C triple bond D quadruple bond

3. Compared to ionic compounds, molecular compounds generally have A good conductivity B greater densities C more chemical bonds D a low boiling point

2. A nitrogen molecule (N2) has one triple bond. How many electrons do the nitrogen atoms share? A 1 B 3 C 4 D 6

4. Compared to ionic compounds,

molecular compounds generally have A stronger chemical bonds B poor conductivity C a high melting point D lower densities


5. The chemical bond formed when two atoms share electrons is called a(n) ionic bond.

6. Covalent bonds usually form when a nonmetal combines with a(n) metal.

7. A(n) ion is a neutral group of atoms joined by covalent bonds.

8. If a molecule contains polar bonds, the molecule may or may not be polar overall.

9. In a(n) polar bond, one atom pulls on the shared electrons more than the other atom.

10. The forces between molecules are much stronger than the forces between ions.

145G

Name Date Class

Bonding in Metals

I get it! Now I know that a metal crystal consists of


1a. IDENTIFY What accounts for the properties of metals?

b. EXPLAIN Explain why metals are good conductors of electric current.

c. APPLY CONCEPTS Why is it safer to use a nonmetal mixing spoon when

cooking something on a hot stove?

I get it! Now I know that properties of metals include


151B

What Is the Structure of a Metal Crystal?

What Are Properties of Metals?

Name Date Class

Bonding in Metals On a separate sheet of paper, explain how the behavior of valence electrons contributes to the following properties of metals: luster, malleability, ductility, high electrical conductivity, and high thermal conductivity.

151C

Name Date Class

Bonding in Metals

1. What do points a and b represent?

2. What action is modeled by the diagram? Explain.

3. How does metallic bonding explain the result at point c? Match each property of metal with its description by writing the letter of the correct description in the right column on the line beside the property in the left column.

4. luster

5. ductility

6. malleability

7. thermal conductivity

8. electrical conductivity

a. easily beaten into complex shapes

b. conducts electric current well

c. shiny and reflective

d. easily bent and pulled into thin strands

e. conducts heat well

9. metallic bond

10. alloy

151D

Understanding Main Ideas Use the diagram to answer the following questions on a separate sheet of paper.

Building Vocabulary On a separate sheet of paper, write a definition for each of these terms.

Name Date Class

Bonding in Metals How Hard? Some metals, such as copper and gold, are also minerals. A mineral is a naturally occurring solid that has a crystal structure and a definite chemical composition. Their crystal structure makes minerals hard. Nonetheless, there is considerable variation among minerals in hardness. Talc is the softest mineral, and diamond is the hardest. Mohs Scale of Hardness, which is shown below, is used to classify minerals and other substances according to their hardnesses. An object on the scale will scratch anything with a lower number, but will be scratched by anything with a higher number. The table includes some everyday objects in parentheses for comparison.

1. Which minerals will scratch quartz? How do you know? 2. According to the information in the table, do you think that you

could scratch a copper coin with a knife blade? Explain your answer. 3. How could you determine the hardness rating for a mineral not listed

on the scale?

151E

Read the passage and look at the table below it. Then use a separate sheet of paper to answer the questions that follow the table.

Mineral (Object) Hardness

(knife blade) 5.5

feldspar 6

(steel file) 6.5

quartz 7

topaz 8

corundum 9

diamond 10

Mineral (Object) Hardness

talc 1

(asphalt) 1.3

gypsum 2

(fingernail) 2.5

calcite 3

(copper coin) 3

fluorite 4

apatite 5

Name Date Class

Bonding in Metals Write the letter of the correct answer on the line at the left.

1. Why are alloys generally used to make everyday objects? A Alloys are often stronger and less reactive

than pure metals. B Alloys have higher melting points than pure

metals. C Alloys are less expensive to produce than

pure metals. D Alloys have ionic bonds instead of metallic

bonds.

3. Which of the following is NOT a

property of metals? A ductile B good electrical conductor C good thermal insulator D malleable

2. Metallic bonding is A a type of covalent bond B a type of ionic bond C an attraction between positive and

negative ions D an attraction between positive ions and

electrons

4. At room temperature, most metals are A liquid B solid C gas D an alloy


5. An attraction between a positive metal ion and surrounding electrons is a(n) bond.

6. Metals typically have melting points.

7. The metal fins that cool a motorcycle’s engine make use of the high conductivity of metals.

8. Metals are often used to make wire because they are .

9. Metals are used in electrical wires because they have high conductivity.

10. Nonmetals are unlikely to form metallic bonds because their are strongly held.

151F

Name Date Class

Observing Chemical Change 1a. REVIEW The freezing point of water is a (physical/chemical) property. The ability

of oxygen to react with iron to cause rust is a (physical/chemical) property.

b. POSE QUESTIONS When silver coins are found in ancient shipwrecks, they are coated with a black crust. Ask a question that could help you determine whether the silver underwent a chemical change or a physical change. Explain.

I get it! Now I know that two ways changes in matter can be described are


2a. LIST What changes in physical properties can be used as evidence that

a chemical reaction has occurred?

b. APPLY CONCEPTS What evidence of a chemical change is observed when rust forms on iron?

c. COMPARE AND CONTRAST How are endothermic and exothermic reactions the same? How are they different?

I get it! Now I know that two kinds of changes you can observe when chemical reactions

occur are


169B

How Can Changes in Matter Be Described?

How Do You Identify a Chemical Reaction?

Name Date Class

Observing Chemical Change

On a separate sheet of paper, describe what happens when reactants form products.

169C

Name Date Class

Observing Chemical Change

7. Any change that alters a substance without changing it into another substance is a(n) change.

8. is anything that has mass and takes up space.

9. A reaction that releases energy in the form of heat is called a(n) reaction.

10. A(n) reaction is a reaction in which energy is absorbed.

11. A chemical change is also referred to as a(n) .

12. A(n) is a solid formed from liquid reactants during a chemical reaction.

169D

Understanding Main Ideas Complete the following table. Describe changes in properties that you might notice during each process and state whether the changes are chemical or physical.

Changes in Matter

Event Observable Changes Type of Change

Baking a cake 1. 2.

Burning a log 3. 4.

Freezing water 5. 6.


Name Date Class

Observing Chemical Change Separation Science A mixture is a combination of two or more pure substances in which the substances do not combine to form new material. Therefore, you should be able to separate a mixture into the substances that make it. There are several ways to separate mixtures. Figure 1 shows a mixture of sand and water being separated by filtration. The salt in a solution of salt water can be separated by evaporation, shown in Figure 2. When you let the sand particles in a mixture of sand and water settle to the bottom of a container, you are using a method called decanting, shown in Figure 3. 1. Using Figure 1, explain the process of filtration. Give another

example of filtration used to separate a mixture. 2. Discuss a use for evaporation. 3. What types of mixtures could be separated by decanting? Is

laboratory equipment necessary for decanting a mixture? Why or why not?

4. Would a separation of the types described above cause a chemical change or a physical change? Explain your answer.

169E

The figures show methods for separating mixtures. Read the passage and study the figures. Then answer the questions that follow on a separate sheet of paper.

Name Date Class

Observing Chemical Change Write the letter of the correct answer on the line at the left.

1. Which of the following is true about chemical reactions? A They are accompanied by changes in

energy. B They form new substances with new

properties. C both A and B D neither A nor B

3. Which of the following is NOT a physical property? A melting point B state of matter C density D flammability

2. In an endothermic reaction, energy is A absorbed B released C converted to mass D synthesized

4. Substances formed as a result of a chemical reaction are called A catalysts B precipitates C products D reactants


5. In an exothermic reaction, products have more energy than reactants.

6. Water boils at 100°C. This is an example of a chemical property.

7. Substances that enter into a chemical reaction are called products.

8. The ability to react with oxygen is an example of a chemical property.

9. Another name for a chemical change is a chemical bond.

10. In a physical change, some of the physical properties of the substance may be altered and the chemical composition remains the same.

169F

Name Date Class

Describing Chemical Reactions 1a. EXPLAIN What do the formulas, arrows, and plus signs tell you in

a chemical equation?

b. INTERPRET DATA Write the chemical equation for the following reaction: The elements sodium and chlorine combine to yield the compound sodium chloride.

I get it! Now I know that a chemical equation tells you


2a. INFER If the total mass of the products in a reaction is 90 grams,

what was the total mass of the reactants?

b. APPLY CONCEPTS Balance the equations. • Al + CuO → Al2O3 + Cu • Fe2O3 + C → Fe + CO2 • SO2 + O2 → SO3

181B

What Information Does a Chemical Equation Contain?

How Is Mass Conserved During a Chemical Reaction?

Name Date Class

c. ANSWER How is matter conserved in a chemical reaction?

I get it! Now I know that the mass of reactants and products


Describing Chemical Reactions 3a. CLASSIFY What type of chemical reaction is shown in the chemical equation below?

Zn + 2 HCl → H2 + ZnCl2

b. DRAW CONCLUSIONS The elements iron and oxygen can react to form the compound iron oxide. What type of reaction is this? Explain.

I get it! Now I know that three types of chemical reactions are


181C

What Are Three Types of Chemical Reactions?

Name Date Class

Describing Chemical Reactions On a separate sheet of paper, identify the basic structure of a chemical equation, explain why an equation must be balanced, and describe the three types of chemical reactions.

181D

Name Date Class

Describing Chemical Reactions Answer questions 4 and 5 on a separate sheet of paper.

4. Describe in words the reaction represented by the equation and include a description of the composition of each kind of molecule. 2 H2 + O2 → 2 H2O

5. Use the law of conservation of mass to explain why the equation in question 4 is balanced.

6. chemical equation

7. decomposition reaction

8. coefficient

9. product

10. reactant 11. synthesis reaction 12. replacement reaction 13. conservation of mass

a. substance present after a reaction

b. reaction in which substances combine to form a more complex compound

c. principle that states that matter is not created or destroyed during a chemical reaction

d. reaction in which one element replaces another in a compound

e. substance present before a reaction

f. number telling how many molecules of a substance are involved in a chemical reaction

g. reaction in which compounds are broken down into simpler substances

h. uses symbols and formulas to show chemical reactions

181E

Understanding Main Ideas Complete the table. Balance each equation. Then indicate whether the reaction is a synthesis, decomposition, or replacement reaction.

Given Equation Balanced Equation Type of Reaction

1. FeS + HCl → FeCl2 + H2S a. b. 2. Na + F2 → NaF a. b. 3. HgO → Hg + O2 a. b.


Name Date Class

Describing Chemical Reactions The Decomposition of Water You have learned that hydrogen gas and oxygen gas can react to produce water. The reverse of this reaction can also occur. In other words, water can be broken down to make hydrogen gas and oxygen gas. The breakdown of water is a decomposition reaction.

H2O → H2 + O2 Water Hydrogen gas Oxygen gas

For this reaction to occur, there must be an electric current through the water as shown in the figure below. Two wires are connected to a battery, and the free ends of the wires are put into a beaker of water that contains a small amount of sulfuric acid. The sulfuric acid helps to increase the flow of current through the water.

1. Write a balanced equation for the decomposition of water. 2. How many atoms of hydrogen are on the left side of the balanced

equation? How many oxygen atoms? How many hydrogen atoms are on the right side of the balanced equation? How many oxygen atoms?

3. The water in a beaker has a mass of 200 g. An electric current is turned on in the water for two hours. Afterward the water has a mass of only 176 g. What happened to the missing mass?

4. Looking at the figure above, how can you tell that a reaction is occurring?

181F

Read the passage and study the figure. Then answer the questions that follow on a separate sheet of paper.

Name Date Class

Describing Chemical Reactions Write the letter of the correct answer on the line at the left.

1. In a balanced chemical equation, A atoms are conserved B coefficients are equal C molecules are equal D energy is not conserved

3. The reaction in which hydrogen and oxygen are produced by running an electric current through water is an example of A single replacement B decomposition C synthesis D double replacement

2. When the equation Al + Br2 → AlBr3 is balanced, the coefficient for Al is A 1 B 2 C 3 D 4

4. A reaction that has two compounds

as reactants and two compounds as products is most likely a A synthesis reaction B single replacement reaction C double replacement reaction D decomposition reaction


5. A number written in front of a chemical formula is a(n) .

6. The principle that states that matter is neither created nor destroyed during a chemical reaction is called the law of .

7. The production of carbon dioxide during the burning of a fuel is an example of a(n) reaction.

8. In a chemical equation, the arrow is read as .

9. In the balanced chemical equation for the formation of ammonia (NH3) from nitrogen (N2) and hydrogen (H2), the sum of the coefficients is .

10. The law of conservation of mass was first demonstrated by the French chemist .

181G

Name Date Class

Controlling Chemical Reactions

I get it! Now I know that in order for reactions to get started


1a. DESCRIBE To slow down a reaction, you can (increase/decrease) the

concentration of the reactants.

b. COMPARE AND CONTRAST What would react more quickly in the air, a pile of grain or a cloud of grain dust? Explain.

c. EXPLAIN How do enzymes speed up chemical reactions in your body?

I get it! Now I know that the rate of a chemical reaction can be affected by


187B

How Do Reactions Get Started?

What Affects the Rate of a Chemical Reaction?

Name Date Class


On a separate sheet of paper, identify the relationship between activation energy and the start of a chemical reaction. Then describe the factors that affect reaction rates.

187C

Name Date Class


1. Use what you know about endothermic and exothermic reactions to explain the differences in the graphs above.

2. Why is the activation energy pictured as a hill in the two diagrams?

3. Explain how adding heat to the reactions shown in the diagram would change the rate of these chemical reactions. Name two other ways to change the rate of a chemical reaction.

4. concentration

5. enzyme

6. inhibitor

187D

Understanding Main Ideas Use the figures below to answer questions 1–3. Write your answers on a separate sheet of paper.

Building Vocabulary Write a definition for each of these terms on the lines below.

Name Date Class

Controlling Chemical Reactions Flameless Ration Heaters Suppose that you are a soldier on patrol far from your base camp. The weather is very cold and you wish you had something warm to eat. However, you aren’t carrying a camp stove and it would be too dangerous to light a fire because the smoke would reveal your position. Luckily, you have a Meal Ready to Eat (MRE) and a Flameless Ration Heater (FRH) in your backpack. (A ration is a portion of food.)

An MRE is a meal, such as beef stew, inside a special pouch made of aluminum foil and plastic. To heat your MRE, you slide it into an FRH, as shown in the figure. An FRH is a kind of plastic envelope that contains certain chemicals. When you add water to the FRH, an exothermic reaction occurs. The heat produced by this reaction warms up your meal in about 15 minutes.

The chemicals inside the FRH include magnesium (Mg), iron (Fe), and sodium chloride (NaCl). The reaction that takes place when water is added to an FRH is as follows.

Mg + 2 H2O → Mg(HO)2 + H2 Magnesium Water Magnesium hydroxide Hydrogen gas

The reaction of magnesium and water is normally very slow. As a result, it gives off heat very slowly. In an FRH, however, this reaction occurs much faster and so it gives off heat much faster as well.

1. Iron and sodium chloride are present in an FRH, but they are not reactants in the equation shown above. Why do you think they are included in an FRH?

2. Why do you think an FRH does not come with water already in it?

3. Do you think there is one large piece of magnesium metal or many small pieces of magnesium metal in an FRH? Explain.

4. Why is it important that the reaction in an FRH be fast?

187E

Read the passage and study the figure. Then answer the questions that follow on a separate sheet of paper.

Name Date Class

Controlling Chemical Reactions If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true.

1. Increasing the surface area of the reactants will decrease the rate of the reaction.

2. The amount of a substance in a given volume is the concentration of the substance.

3. The effect of a catalyst on a reaction is to raise the activation energy.

4. Only some reactions require activation energy.

5. A(n) inhibitor decreases the rate of a reaction.


6. The burning of fuels, such as coal, natural gas, or oil, involves a(n) reaction.

7. In an endothermic reaction, the energy of the products is than the energy of the reactants.

8. Increasing the temperature of a reaction will the rate of the reaction.

9. The amount of a substance in a given volume is called .

10. Biological catalysts in the human body are called .

187F

Name Date Class

Understanding Solutions 1a. REVIEW What is a solution?

b. COMPARE AND CONTRAST How are colloids and suspensions different

from solutions?

c. INFER Suppose you mix food coloring in water to make it

blue. Have you made a solution or a suspension? Explain.

I get it! Now I know that classifying mixtures as solutions, colloids, and suspensions is

based on


2. APPLY CONCEPTS Why is salt sprinkled on icy roads and sidewalks?

I get it! Now I know that in a solution, the particles of solute


203B

How Are Mixtures Classified?

How Does a Solution Form?

Name Date Class

Understanding Solutions

On a separate sheet of paper, explain what a solution is and how one is formed.

203C

Name Date Class

Understanding Solutions

1.

2.

3.

Answer the following questions on a separate sheet of paper.

4. Compare and contrast what happens to the particles of an ionic solid and a molecular solid when each mixes with water.

5. What are two ways that solutes affect the properties of solvents?

6. The part of a solution that is present in the smaller amount is the .

7. The part of a solution that is present in larger amount is the .

8. A(n) is a mixture containing small, undissolved particles that do not settle out, but are large enough to scatter light.

9. A mixture in which particles can be seen and easily separated by settling or filtration is called a(n) .

10. A well-mixed mixture that contains a solvent and at least one solute is called a(n) .

203D

Understanding Main Ideas The diagram below shows three mixtures. Identify each mixture as a solution, colloid, or suspension. Explain.


Name Date Class

Understanding Solutions The Chemistry of Ice Cream A colloid is similar to a suspension in that its particles are larger than those of a solution. However, the particles of a colloid, like those of a solution, are small enough that they cannot be separated by settling or filtration. The particles in a colloid are said to be dispersed, rather than dissolved or suspended. Familiar colloids include shaving cream, fog, and smoke. Ice cream is another familiar colloid. The particles in this colloid are solid fat, tiny crystals of ice, and droplets of water. A high concentration of sugars, salts, and proteins is dissolved in the water. Here, air acts something like a solvent. The particles of ice cream are dispersed in many tiny bubbles of air. Ice cream also contains other substances that allow “unlike” compounds to mix and stay mixed under the proper conditions. The unlike compounds in ice cream are water, which is polar, and fat, which is nonpolar. The colloid formed by ice cream remains stable only at cold temperatures. When ice cream is warmed above freezing, its dispersed particles absorb energy and begin to move faster. When the fast-moving particles collide, they sometimes stick together. Eventually, the particles grow so large that they can no longer remain dispersed, and they settle out of the colloid.

1. Suppose the liquid water in ice cream did not have solutes dissolved in it. What effect do you think this would have on ice cream? (Hint: Consider the temperature at which ice cream is kept.)

2. What do you think happens to the air in the colloid when ice cream melts?

3. Look at the diagram above. Why do you think air isn’t added until Step 2 when the mixture is cooled?

4. Milk is also a colloid. It consists mainly of water, proteins, and fat. Which colloid is more stable, milk or ice cream? How do you know?

203E

Solid and liquid ingredients are combined.

Ingredients: milk and cream, sugar, flavoring,

water, fat, proteins, substances to allow unlike

compounds to mix

Mixture is churned and cooled at the same time.

Churning adds air and aids in rapid cooling.

Ice cream is cooled further until it is

completely frozen.

Step 1 Step 2 Step 3

Read the passage and study the flowchart below it. Then use a separate sheet of paper to answer the questions that follow.

Name Date Class

Understanding Solutions Write the letter of the correct answer on the line at the left.

1. Which of the statements about the effect of solutes on solutions is true? A Solutes raise the boiling point of a solvent. B Water with a solute dissolved in it will

freeze at 0°C. C Solutes raise the freezing point of a

solvent. D Antifreeze boils at a lower temperature

than pure water.

3. Which of the following statements

about solutions is NOT true? A Solutions are mixtures. B Solutions contain a solvent dissolved in a

solute. C A solution has the same properties

throughout. D The solute in a solution can be a solid,

liquid, or gas.

2. Brass is a solution in which a solid is dissolved in a(n) A liquid B gas C solid D water

4. Which of the following statements about the particles in a solution is true? A When an ionic solid mixes with water, its

ions repel water molecules. B When a molecular solid mixes with water,

the covalent bonds are broken. C When an ionic solid mixes with water,

water molecules surround each ion. D When a molecular solid mixes with water,

water molecules surround each ion. If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true.

5. If a suspension is allowed to stand, the particles settle out.

6. Solutions and colloids are similar in that both are suspensions.

7. The largest particles in a colloid are smaller than the largest particles in a solution.

8. The freezing point of a solvent decreases as solute is added.

9. Molecular compounds in water conduct an electric current.

10. A characteristic property of a(n) solution is that it can scatter light.

203F

Name Date Class

Concentration and Solubility 1a. DESCRIBE What is a concentrated solution?

b. CALCULATE Find the concentration of a solution with 30 grams of solute in 250 grams of solution.

c. Solution A has twice as much solute as Solution B. Is it

possible for the solutions to have the same concentration? Explain.

I get it! Now I know that the concentration of a solution can be changed by


2a. REVIEW How can you tell when a solution is saturated?

b. CONTROL VARIABLES You are given two white powdery substances.

How would you use solubility to identify them?

c. ANSWER What determines the properties of a solution?

I get it! Now I know that the solubility of a substance can be affected by


211B

How Is Concentration Changed?

CHALLENGE

What Factors Affect Solubility?

Name Date Class

Concentration and Solubility On a separate sheet of paper, explain the difference between concentration and solubility. Then describe how each can be changed.

211C

Name Date Class

Concentration and Solubility

1. What amounts do you compare when measuring concentration?

2. How can you tell that a white powder is salt without tasting it?

3. Which solution will have more gas dissolved in it, a solution under

high pressure or one under low pressure?

4. How does temperature affect the solubility of most solids?

5. dilute solution

6. concentrated solution

7. solubility

8. saturated solution

a. a measure of how much solute can dissolve in a solvent at a given temperature

b. a solution that has so much solute that no more can dissolve

c. a solution that has only a little solute

d. a solution that has a lot of solute

211D

Understanding Main Ideas Answer the following questions in the spaces provided. Use a separate sheet of paper if you need more room.


Name Date Class

Concentration and Solubility Temperature and Solubility One of the factors that affects the solubility of a substance is temperature. The graphs below show how the solubilities of different solids and gases change with the temperature of water.

1. What are the manipulated variables and the responding variables on each graph? 2. What are the general trends in solubility implied by the two graphs? 3. Do all of the solids in the first graph follow the trend? Explain. 4. Which solid shows the greatest change in solubility with temperature? 5. At higher temperatures, gas particles move faster. Use this behavior

to explain the change in solubility of gases.

211E

Study the two graphs. Then use a separate sheet of paper to answer the questions.

Name Date Class

Concentration and Solubility Fill in the blank to complete each statement.

1. A solution in which more solute can be dissolved is called a(n) solution.

2. A solution in which 50 grams of solute is dissolved in 250 grams of solution has a concentration of percent.

3. When saturated solutions are , they usually become unsaturated solutions.

4. Ionic and polar compounds usually dissolve in solvents.

5. The concentration of a solution can be changed by solute.


6. A solution in which only a little solute is dissolved in a certain amount of solvent is called a(n) concentrated solution.

7. As the pressure of the gas over a solution decreases, the solubility of a gas solute in a liquid solvent increases.

8. The solubility of table sugar in water increases as the temperature increases.

9. The solubility of a gas dissolved in a liquid increases as the temperature of the liquid increases.

10. Three factors that affect the solubility of a substance are pressure, the type of solvent, and volume.

211F

Name Date Class

Describing Acids and Bases 1a. DEFINE What is a compound that changes color in an acid called?

metal indicator carbonate

b. EXPLAIN Why are acids described as corrosive?

c. DRAW CONCLUSIONS How might you tell if a food contains an acid?

I get it! Now I know that the properties of acids include


2a. REVIEW The properties of bases are often considered (identical/

opposite) to acids. b. APPLY CONCEPTS In what products are you most likely to find

bases in your home?

c. POSE QUESTIONS The color of hydrangea flowers depends on the amount of

acid or base in the soil. Write a question that helps you determine the

cause of a pink hydrangea.

I get it! Now I know that the properties of bases include


217B

What Are the Properties of Acids?

What Are the Properties of Bases?

Name Date Class

Describing Acids and Bases On a separate sheet of paper, describe how acids and bases are alike and how they are different.

217C

Name Date Class

Describing Acids and Bases

1. When found in foods, what does an acid taste like?

2. When found in foods, what does a base taste like?

3. Compare how an acid and a base will each react with the metals

magnesium, zinc, and iron.

4. Compare how an acid and a base will each react with carbonate ions.

5. What color does an acid turn litmus paper?

6. What color does a base turn litmus paper?

7. What is neutralization?

8. corrosive

9. indicator

217D

Understanding Main Ideas Answer the following questions in the spaces provided.

Building Vocabulary On a separate sheet of paper, write a definition for each of these terms.

Name Date Class

Describing Acids and Bases Acidic Paper From the fifteenth through the eighteenth centuries, the paper in many books was made from linen. Linen is made from the fibers of flax plants. By the nineteenth century, the printing of books had increased dramatically and, as a result, so did the demand for inexpensive paper, In response, a method was developed to produce cheap paper from wood. This process involved the use of a chemical called alum, which greatly increased the acidity of paper. Eventually, this acidity causes such paper to become brittle and fall apart. Thus, many books made during the nineteenth and twentieth centuries are slowly becoming too fragile to read, while older books made with linen paper are often in better condition. Scientists have developed several chemical methods to preserve books made with acidic paper. These methods involve reacting the acid in the paper with a base. The products of these reactions are not acidic, and so the paper is protected from further damage due to acidity. The diagram below illustrates one of these processes. Today, some publishers use acid-free paper in their books. In fact, important documents are sometimes printed on paper that is basic rather than acidic.

1. Is paper made from linen more or less acidic than paper made from wood? Which type of paper lasts longer?

2. The bases used to treat books containing acidic paper are usually gases rather than liquid solutions. Why do you think this is so?

3. Why do you think that printing a document on basic paper will help to ensure that it lasts for a very long time?

4. How might the process of making paper from wood be changed to produce paper that is not acidic?

217E

1. Books are placed in a

special chamber.

4. The gas diethyl zinc is pumped into the chamber. The gas moves between the pages of the closed books and reacts

with acid in the paper.

3. Air in the chamber is replaced with nitrogen gas.

2. Books are dried, removing

water.

Read the passage and study the diagram below it. Then use a separate sheet of paper to answer the questions that follow.

Name Date Class

Describing Acids and Bases Write the letter of the correct answer on the line at the left.

1. Which of the following is NOT a property of an acid? A An acid is corrosive. B An acid turns red litmus paper blue. C An acid reacts with metals and carbonates. D An acid tastes sour.

3. Which of the following best describes

bases? A They feel slippery and taste sour. B They turn red litmus paper blue and react

with metals. C They taste bitter and react with

carbonates. D They turn red litmus paper blue and taste

bitter.

2. Because it wears away certain materials, an acid is described as A concentrated B contaminated C corrosive D carbonated

4. Which of the following best describes

acids? A They taste sour and react with metals. B They taste bitter and react with

carbonates. C They feel slippery and turn blue litmus

paper red. D They react with metals but not with

carbonates.


5. A compound that changes color when it comes into contact with an acid or a base is a(n) .

6. A base react with carbonates.

7. If carbon dioxide gas is produced when dilute acid is applied to a rock’s surface, the rock is most likely made of .

8. Because vinegar contains a(n) , it tastes sour.

9. Many soaps and detergents contain .

10. The acid in the human stomach that aids in digestion is acid.

217F

Name Date Class

Acids and Bases in Solution 1a. IDENTIFY What type of solution has a pH of 7?

acidic basic neutral b. INTERPRET DATA Solution A has a pH of 1.6. Solution B has a pH of 4.

Which solution has a greater concentration of hydrogen ions? Explain.

I get it! Now I know that, in water, acids produce

and bases produce .


2a. DEFINE How is the scientific meaning of salt different

from the common meaning of salt?

b. MAKE GENERALIZATIONS Is the pH of an acid-base

neutralization always 7? Why or why not?

I get it! Now I know that a neutralization reaction produces


223B

What Ions Do Acids and Bases Form in Water?

What Are the Products of Neutralization?

Name Date Class

Acids and Bases in Solution On a separate sheet of paper, use the reaction between hydrochloric acid (HCl) and potassium hydroxide (KOH) to describe a neutralization reaction in terms of reactants, products, litmus paper, and pH.

223C

Name Date Class

Acids and Bases in Solution

5. What is the difference between a strong acid and a weak acid?

6. What is the difference between a strong base and a weak base?

7. Which solution has a greater concentration of hydrogen ions (H+), a solution with a pH of 3 or one with a pH of 7? Explain.

8. What are the products formed when a base reacts with an acid?

9. What is the pH of a neutral solution?

10. hydrogen ion

11. pH scale

12. neutralization

13. salt

14. hydroxide ion

a. ionic compound that can form from the reaction of an acid with a base

b. reaction between an acid and a base

c. H+

d. series of numbers that indicates the concentration of hydrogen ions in solution

e. OH–

223D

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Substances with a pH in this range are 1. .

Substances with a pH in this range are 2. .

In water, they form 3. ions.

In water, they form 4. ions.

Understanding Main Ideas Complete the concept map shown below and answer the following questions on a separate sheet of paper.


Name Date Class

Acids and Bases in Solution Swimming Pool Basics If chemicals are not added to swimming pools, tiny organisms such as bacteria and algae can multiply in the water. Algae can turn the water in a swimming pool cloudy and make the sides and bottom of the pool slimy. Disease-causing bacteria can make swimmers sick. One chemical added to pools contains hypochlorite ions (OCl−). A hypochlorite ion reacts with water to produce hypochlorous acid (HOCl) and a hydroxide ion. Hypochlorous acid kills algae and bacteria. The equation for this reaction is:

OCl− + H2O → HOCl + OH− Hypochlorite ion Water Hypochlorous acid Hydroxide ion

The amount of hypochlorous acid that is produced by this reaction depends on the pH of the pool water. The ideal pH for the above reaction is 7.4. Therefore, the pH of the pool water must be carefully controlled. If the pH is too high (above 7.6), the reverse of the reaction above occurs! A hydroxide atom reacts with hypochlorous acid to produce a hypochlorite ion and water. As a result, there will not be enough hypochlorous acid in the pool water to control the bacteria and algae. Problems also occur when the pH of the pool water is too low (less than 7.2). Pool water having a low pH can damage the sides and bottom of the pool. Pool water having pH levels that are either too high or too low can cause eye irritation in swimmers. The graph below shows how the relative amounts of hypochlorous acid and hypochlorite ions vary with the pH of the pool water.

1. What happens to the amount of hypochlorous acid (HOCl) in a swimming pool as the pH increases? What happens to the amount of hypochlorite ions (OCl–)?

2. What type of chemical could you add to a swimming pool to decrease the pH of the water? Explain.

3. What type of chemical could you add to a swimming pool to increase the pH of the water? Explain.

223E

Read the passage and study the graph below it. Then use a separate sheet of paper to answer the questions that follow.

Name Date Class

Acids and Bases in Solution

Write the letter of the correct answer on the line at the left.

1. Which of the following substances is NOT an acid? A HCl B H2SO4

C NaOH D HNO3

3. Which of the following substances is most likely to have a pH close to 7? A lemon B antacid C ammonia D vinegar

2. The negative ion found in bases is the A hydroxide ion B hydrogen ion C carbonate ion D water ion

4. Which of the following statements is NOT true about neutralization? A An acid and a base are the reactants. B A salt and water are the products. C There is no color change in litmus paper

when the reaction is over. D It produces an acid-base mixture that

is more acidic than both the individual starting solutions.


5. A solution with a pH of 2 is acidic than a solution with a pH of 6.

6. Chemists use the to express the concentration of hydrogen ions in solution.

7. An acid produces ions in water.

8. Substances with pH values close to 14 are strong .

9. A strip of blue litmus paper placed in a beaker of vinegar will turn .

10. A base produces ions in water.

223F

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