Chemistry - School District of Haverford Township · 3 T. Trimpe 2000 Name_____ Metric Conversions Fill in the boxes in the stair step diagram. Try these conversions, using the ladder

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Chemistry 2017 - 2018

Student Name _________________________________ Teacher Name_________________________________

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Tops • Objective:

o Use the materials given to make a top that spins for the longest amount of time.

• Materials:

o Paper Plate (can cut to any size) o Duct Tape o Up to 8 Pennies o Pencil (can manipulate size)

• Rules:

• You can use either side of the pencil (eraser or point) • You must use at least one penny. • In order to be eligible, the top must spin for a minimum of 10 seconds. • You only get one paper plate!! Plan before you cut!!

• What are some qualities you should consider before making your top?

• An independent variable is the variable you have control over, that you can manipulate. What are the independent variables in this experiment?

• A dependent variable is the variable that changes because you have changed the independent variable. What is the dependent variable in this experiment?

• This is an experimental design activity. What do you think that means?

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T. Trimpe 2000 http://sciencespot.net/

Name_________________________

Metric Conversions Fill in the boxes in the stair step diagram.

Try these conversions, using the ladder method.

1000 mg = _______ g 1 L = _______ mL 160 cm = _______ mm

14 km = _______ m 109 g = _______ kg 250 m = _______ km Compare using <, >, or =.

56 cm 6 m 7 g 698 mg

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T. Trimpe 2000 http://sciencespot.net/

Name_________________________

Metric Conversions Write the correct abbreviation for each metric unit.

1) Kilogram _____ 4) Milliliter _____ 7) Kilometer _____

2) Meter _____ 5) Millimeter _____ 8) Centimeter _____

3) Gram _____ 6) Liter _____ 9) Milligram _____ Try these conversions, using the ladder method.

10) 2000 mg = _______ g 15) 5 L = _______ mL 20) 16 cm = _______ mm

11) 104 km = _______ m 16) 198 g = _______ kg 21) 2500 m = _______ km

12) 480 cm = _____ m 17) 75 mL = _____ L 22) 65 g = _____ mg

13) 5.6 kg = _____ g 18) 50 cm = _____ m 23) 6.3 cm = _____ mm

14) 8 mm = _____ cm 19) 5.6 m = _____ cm 24) 120 mg = _____ g Compare using <, >, or =.

25) 63 cm 6 m 27) 5 g 508 mg 29) 1,500 mL 1.5 L

26) 536 cm 53.6 dm 28) 43 mg 5 g 30) 3.6 m 36 cm

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Part One: Describing Chemical

Reactions

Chemistry that Applies – Michigan Dept of Education Cluster 1

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MATTER AND ENERGY, CHAPTER 1, READING STUDY GUIDE A 13

SECTION

1.1MATTER HAS MASS AND VOLUME.

Reading Study Guide A

BIG IDEA Everything that has mass and takes up space is matter.

KEY CONCEPT Matter has mass and volume.

Vocabularymatter anything that has mass and takes up spacemass how much matter something containsweight the downward pull of an object because of gravityvolume the amount of space something takes up

Review 1. List two tools a scientist might use.

Take NotesI. All objects are made of matter. (p. 9)

2. Fill in the combination notes for the main idea shown.

MAIN IDEA DETAIL NOTES

1. All objects are made of matter. A. Matter is what makes up all objects and organisms.

B. Matter is __________________________

____________________________________.

C. Two things that are not matter are

____________________________________.

3. In the table below, underline everything that is made of matter.

a book an idea light a feeling

a chair a sound a mountain air

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14 MATTER AND ENERGY, CHAPTER 1, READING STUDY GUIDE A

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II. Mass is a measure of the amount of matter. (p. 10)

4. Fill in the four-square diagram for mass.

MASS

Characteristics

Nonexamples

DefinitionHow much matter something contains.

Examples

A–B. Measuring Mass and Measuring Weight (p. 10)

5. Circle the object on each balance that has more mass.

MILK

6. Do mass and weight mean the same thing? Remembering that gravity is less on the Moon than it is on Earth, which measurement—mass or weight—changes on the Moon?

III. Volume is a measure of the space matter occupies. (p. 11)

7. Fill in the four-square diagram for volume.

VOLUME

Characteristics

Nonexamplesthe weight of a basketball

Definition

Examplesthe size of a basketball

A–B. Determining Volume by Formula and Determining Volume by Displacement (pp. 12–13)

8. The volume of an object can be determined using the formula l ! w ! h. What do the letters (variables) stand for?

9. What is another way to determine an object’s volume?

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SECTION

1.1

20 MATTER AND ENERGY, CHAPTER 1, REINFORCING KEY CONCEPTS

MATTER HAS MASS AND VOLUME.

Reinforcing Key Concepts

BIG IDEA Everything that has mass and takes up space has matter.

KEY CONCEPT Matter has mass and volume.

1. All objects are made of matter. Matter is what makes up all of the objects and living organisms in the universe. Matter is anything that has mass and takes up space. What is matter made of? Name two things that are not made of matter.

2. Mass is a measure of the amount of matter. When you measure mass, you compare the mass of the object with a standard amount, or unit of mass. When you measure weight, you are measuring the downward pull on an object due to gravity. Look at the two pictures below showing a bowling ball being measured for weight and for mass. In which picture is the bowling ball’s mass being measured? How can you tell?

A

B

3. Volume is a measure of the space matter occupies. The amount of space that matter in an object occupies is called an object’s volume. A bowling ball and a basket ball take up approximately the same amount of space, therefore, the two balls have about the same volume. Volume is calculated by multiplying the length, width, and height of an object. You would like to calculate the volume of a brick. The brick is 32 cm long, 20 cm high, and 15 cm wide. Use the formula V = lwh to calculate the volume of the brick. If you used the displacement method to determine volume, how many milliliters would the brick take up?

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Introduction to Chemistry – Chem4Kids Please log on to www.chem4kids.com - Click on Matter Matter Overview

• Read through all the information on this page. • Summarize matter in three short phrases

o o

o

• At the bottom of the page: o Click on Next Page on Matter. It will bring you to “States of Matter.”

States of Matter

• Read through all the information on this page. • Each state is also known as a ____________________. • What physical force commonly causes elements and compounds to move

from one phase to another?

• At the bottom: • Click on Next Page on Matter. It will bring you to “Changing States of

Matter” Changing States of Matter

• Read through all the information on this page. • What is required for matter to change from one state to another?

o

o

• What happens to water molecules as they approach freezing, and melting points?

• At the bottom: • Click on Next Page on Matter and read the section called “Liquid to

Gas and Back to Liquid.” • Then, click on Next Page on Matter and It will bring you to “Chemical

Changes Versus Physical Changes.”

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Chemical Changes Versus Physical Changes • Read through all the information on this page. • Describe and give an example of each type of change.

o Chemical –

o Physical –

• At the bottom: • Click on Next Page on Matter. It will bring you to “Solid Basics.”

Solid Basics

• Read through all the information on this page. • What are some characteristics of a solid?

o o

• How do the atoms in a solid behave?

• At the bottom: • Click on Next Page on Matter. It will bring you to “Liquid Basics.”

Liquid Basics

• Read through all the information on this page. • What are some characteristics of a liquid?

o o

• How do the molecules in a liquid behave?

• At the bottom: • Click on Next Page on Matter and read the section called “Evaporation

of Liquids.” • Then, click on Next Page on Matter and It will bring you to “Looking for a

Gas.”

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Looking for a Gas

• Read through all the information on this page. • What are some characteristics of a gas?

o o

• How do the molecules in gas behave?

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Lesson 1: Mixing It Up Each morning we begin our day by mixing things. It may be our favorite cereal and milk, toast with butter, or cream and coffee. It doesn’t end there. As the day continues, we use a wide array of mixed substances such as foods, hair sprays, liquid soaps, fertilizers for plants, gasoline and oil for the lawn mower, glue, detergents for washing clothes, and the flour, eggs, sugar and baking powder for making cakes. Mixing substances together is something we do (or have done for us) all the time. Asking questions about these mixtures will help us to look more closely at what is happening when things are mixed.

1. What types of things do you mix on a daily basis? Make a list of 5 combinations that you mix together every day.

2. Examine your materials. Starting Substances

Common Name Description

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3. Pick four (4) combinations of two (2) substances. List them in the left

column below. Mix each of the combinations. Write a description of what you saw when the two substances were mixed in the middle column. Write a description of the substance that was created when the two were mixed in the right column.

Substances to mix Description of What Happened

Description of Ending Substance

4. Pick four (4) combinations of three (3) substances. List them in the left column below. Mix each of the combinations. Write a description of what you saw when the three substances were mixed in the middle column. Write a description of the substance that was created when the three were mixed in the right column.

Substances to mix Description of What Happened

Description of Ending Substance

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Think and Write: 5. Do you think any of the demonstrations DID NOT produce new

substances? How can you tell?

6. Do you think any of the demonstrations DID produce new substances? How can you tell?

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Lesson 2 – Is it a New Substance? Objective: To perform, observe, and describe a reaction in order to find evidence for the formation of new substances.

Reaction #1: Rusting Iron

Procedures:

1. Examine your group’s 2 starting substances, steel wool and vinegar, and write a description in the chart on the next page. Use at least 3 descriptive terms from our list.

2. Place the steel wool in a beaker. Pour enough vinegar over the steel wool to cover it. Swirl the wool and vinegar making sure that the vinegar has come in contact with all the steel wool. The vinegar will remove an oily protective coating from the steel wool and leave the thin strands of steel wool.

3. Remove the steel wool from the beaker and blot it very dry with a paper towel. Loosen the strands of the steel wool. Place it in a plastic cup and observe what happens after 10 minutes. Record your observations in the chart.

Reaction #2: Baking Soda and Vinegar Procedures:

1. Observe the 2 starting substances, baking soda and vinegar, and write a description below for each. Be sure you use at least 3 descriptive terms for each.

2. Watch as the baking soda and vinegar are combined in a beaker.

Record your observations in the chart on the next page.

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ReactionsReactions Starting Starting

substance #1substance #1 Starting Starting

Substance #2Substance #2 ObservationsObservations Ending Ending

SubstanceSubstance Reaction #1 Rusting Iron

Reaction #2 Baking Soda and Vinegar

Conclusion and Reflection:

1. Based on your observations, what ending substance is/are formed for both reactions?

• Reaction #1:

• Reaction #2:

2. Based on what you saw in this lab, do you think new substances can

be formed when combining and mixing different substances together?

3. If you think any new substances were formed in either reaction, how

could this be explained? Where would the new substances come from?

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SECTION

1.2MATTER IS MADE OF ATOMS.



KEY CONCEPT Matter is made of atoms.

Vocabularyatom the smallest basic unit of mattermolecule two or more atoms bonded together

Review 1. Fill in the concept map for matter.

Matter

has

has

Take NotesI. Atoms are extremely small. (p. 16)



1. Atoms are extremely small. A. An atom is the smallest basic unit of matter.

B. The idea of atoms dates back to _________________

_____________________________________________.

C. Today scientists know of more than _______________

_____________________________________________.

A. Atoms (p. 17)

3. Can you see an individual atom? Why or why not?

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4. Which of the objects below is made of atoms? How do you know?

B. Molecules (p. 18)

5. Fill in the four-square diagram with information about molecules.

MOLECULE

Characteristicscan be made of atoms

that are different or alike

Nonexamplesa hydrogen atom

Definition

Examples

II. Atoms and molecules are always in motion. (p. 19)



1. Atoms and molecules are always in motion.

A. Dust particles show that ______________

___________________________________.

B. Food coloring shows that water

molecules, also, are ___________________

___________________________________.

C. Even molecules in solid objects

___________________________________.

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SECTION

1.3MATTER COMBINES TO FORM DIFFERENT SUBSTANCES.



KEY CONCEPT Matter combines to form different substances.

Vocabularyelement a substance with only one type of atomcompound a substance with atoms of more than one type bonded togethermixture a combination of one or more substances that can be separated physically

Review 1. What is all matter made of?

Take NotesI. Matter can be pure or mixed. (p. 21)



1. Matter can be pure or mixed. A. Often the difference between pure and mixed substances can only be seen at the molecular or atomic level.

B. A pure substance has ________________.

C. The components of a pure substance can

be either ____________________________

____________________________________.

D. Mixed substances have ______________.

A. Elements and Compounds (pp. 22–23)

3. Bronze is made by combining the element copper with the element tin. Is pure bronze an element? Why or why not?

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4. Fill in the description wheel diagram for compound.

table

salt

water

substanceCOMPOUND

B. Mixtures and Comparing Mixtures and Compounds (pp. 23–24)

5. Fill in the four-square diagram for mixture.

MIXTURE

Characteristics

Nonexamplestable salt

Definition

Examples

6. Fill in the chart comparing mixtures and compounds.

Substances That Make It Up

Can Be Separated By Proportions

compound change to new substances

fi xed

mixture physical means

II. Parts of mixtures can be the same or different throughout. (p. 25)

7. What is a heterogeneous mixture? What is a homogeneous mixture?

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SECTION

1.4MATTER EXISTS IN DIFFERENT PHYSICAL STATES.



KEY CONCEPT Matter exists in different physical states.

Vocabularystates of matter the different forms in which matter can existsolid a substance with a fi xed volume and a fi xed shapeliquid a substance with a fi xed volume but no fi xed shapegas a substance with no fi xed volume or shape

Review 1. What tiny particles make up matter?

Take NotesI. Particle arrangement and motion determine the state of

matter. (p. 27)

2. Fill in combination notes for the main idea shown.


1. Particle arrangement and motion determine the state of matter.

A. Three states of matter:

____________________________________

B. From one state to another, molecules do

not _________________________________.

C. From one state to another, arrangement of

molecules does _______________________.

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II. Solid, liquid, and gas are common states of matter. (p. 28)

3. Each sketch shows the same substance in three different states. Below each sketch, write whether it is a solid, liquid, or gas.

A. B. C.

III. Solids have a defi nite volume and shape. (p. 30)



1. Solids have a defi nite volume and shape.

A. The molecules in a solid are in fi xed positions and close together.

B. Molecules can vibrate but do not

____________________________________

C. The particles in some solids occur

____________________________________

IV. Liquids have a defi nite volume but no defi nite shape. (p. 31)

5. How are molecules in a liquid arranged?

V. Gases have no defi nite volume or shape. (p. 32)

6. What is the difference between molecules of a gas and molecules of a liquid?

A–B. Gas Composition and Gas Behavior (pp. 32–33)

7. Fill in the chart with information about how gases change in the given conditions.

Change Result

If temperature remains the same and pressure goes up, volume goes ____________.

If volume remains the same and temperature goes up, pressure goes ____________.

If pressure remains the same and temperature goes up, volume goes ____________.

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Lesson 4: Does the Mass Change? Objective: Students will observe reactions involving physical changes such as crumpling, melting, dissolving and boiling; they will explore and discuss their thinking about the mass changes that occur. 1. Write and explain your prediction for each of the demonstrations listed

below. • Demonstration 1: Which has more mass, a tightly wadded ball of steel

wool or the same steel wool stretched and pulled apart – or are they the same?

• Demonstration 2: How does the mass of a glass of water with an ice

cube in it change as the ice cube melts and eventually disappears? • Demonstration 3: Observe a teaspoon with sugar and a glass of warm

water. Then stir the sugar into the glass of warm water until it has dissolved. How does the initial mass of the teaspoon of sugar and the glass of water compare to the mass of the dissolved sugar and water?

• Demonstration 4: How would the mass change if you boiled a beaker of

water for 10 minutes?

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1. Share and debate your predictions with your team. • Your predictions don’t have to be the same as those of your

team members

2. Choose one spokesperson for your team. 3. Share your predictions and reasoning of your team with the whole

class. • Make sure you tell the class if not everyone agrees on any of

your predictions or reasons.

4. Get a class tally for each prediction. • How many students think the mass would increase, decrease or

stay the same?

Steel Wool Water & Ice Cube Water & Sugar Boiled Water Crumpled

Stretched

Same

Same

Same

Same

5. How could you test your predictions, and prove or disprove them?

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Lesson 5: Gathering Evidence About Mass from Experiments

How can we test the predictions you made in the last lesson? Did someone say, “By actually finding the mass of the materials?” Sure. In this lesson, you will perform the same activities that your teacher demonstrated. You will use a balance or scale to actually mass the substances and then compare these results to your predictions. Key Question: How do your predictions compare to the actual changes in mass of the substances? • Demonstration 1: Which has more mass, a tightly wadded ball of steel wool or

the same steel wool stretched and pulled apart?

Substance Tightly wadded steel wool

Stretched steel wool

Difference

Steel Wool

• Demonstration 2: How does the mass of a glass of water with an ice cube in it

change as the ice cube melts and eventually disappears? Substance Beginning Mass Ending Mass Difference Ice / Water

• Demonstration 3: Observe a teaspoon with sugar and a glass of warm water.

Then stir the sugar into the glass of warm water until it has dissolved. How does the initial mass of the teaspoon of sugar and the glass of water compare to the mass of the dissolved sugar and water? Substance Beginning Mass Ending Mass Difference

Sugar / Water

• Demonstration 4: How would the mass change if you boiled a beaker of water

for 10 minutes? Substance Beginning Mass Ending Mass Difference

Boiling Water

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Think and Write:

1. Did your results help to prove or disprove your predictions?

2. What must happen during any change for the mass of the materials to increase or decrease?

3. In which of the experiments did the mass decrease significantly?

4. What was different about that experiment from the others where there was no mass change?

5. What are all substances made of? Use as much detail as you can.

6. Did the mass change for each of the following materials? Why or why not? Use molecules in each explanation. Draw a picture that shows what is happening to the molecules.

a. Steel wool

b. Water and ice

c. Sugar and water

d. Boiling water

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7. Are these changes physical or chemical changes? Explain your answer.

8. Predict what would happen to the mass of a cold glass of water on a humid summer day? Explain your prediction.

9. Predict what would happen to the mass of a car that gets very rusty over several years. Explain your prediction.

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MATTER HAS OBSERVABLE PROPERTIES.


BIG IDEA Matter has properties that can be changed by physical and chemical processes.

KEY CONCEPT Matter has observable properties.

Vocabularyphysical property a characteristic of a substance that can be observed without changing the substancedensity a measure of how much matter is in a given volume of a substancephysical change a change in any physical property of a substancechemical property a property that describes how a substance combines with another to form a new substancechemical change the change of one substance into another substance

Review 1. Fill in the concept map for matter.

MATTER

has exists inis made of

Take NotesI. Physical properties describe a substance. (p. 41)

2. Fill in the magnet word diagram for the main idea shown.

PHYSICALPROPERTIES

observed without changing identity

volume

mass

SECTION

2.1

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A. Physical Properties and Density (pp. 42–43)

3. Fill in the magnet word diagram for the main idea shown.

DENSITYmeasurement

units of g/cm3

4. The formula for density is D ! m/V. What is the density of a wooden board that has a mass of 400 g and a volume of 500 cm3?

B. Physical Changes (p. 44)

5. Fill in the main-idea web for the main idea shown.

A physical change is a changein any physical property of a substance.

In a physical change, the substance

itself does not __________________.

Example ________________________

_________________________________.

A change of state is an example

of a ________________________.

II. Chemical properties describe how substances form new substances. (p. 46)

6. Why is the ability to burn defi ned as a chemical property instead of a physical property?

A–B. Chemical Properties and Changes and Signs of a Chemical Change (pp. 46–48)

7. List and describe four signs of a chemical change.

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Lesson 6: Does the Mass Change in Chemical Reactions?

Objective: Students will observe and make predictions about whether the mass changes in a chemical reaction. Then they will perform an experiment to test their hypothesis. Key Question: How can you predict if the mass of a substance will change during a chemical reaction? PART ONE: PREDICTION (Open System) Do you think a new substance was formed when you mix baking soda & vinegar? Why or why not? Prediction: Did the mass increase, decrease, or remain the same during this reaction? Explain your reasoning. PART TWO: EXPERIMENT

• Plan, as a group, how to conduct an experiment to prove your prediction. Write out your plan in steps on the table below,

Open System

Steps to Conduct Experiment Measurements

Before Measurements

After

1. Put on safety glasses.

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Closed System Steps to Conduct Experiment Measurements

Before Measurements

After

1. Put on safety glasses.

PART THREE: ANALYSIS

1. Did your results of the baking soda & vinegar in the open system help prove or disprove your predictions?

2. Were there any substances that left the reaction or that were added to the reaction?

o Open System

o Closed System

3. What is the difference between an open system and a closed system?

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4. Did the mass change during this experiment? If so, how? o Open System

o Closed System

5. How were the ending substances different from the starting substances?

6. Does this indicate that the change was a physical change or a chemical change?

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CHANGES OF STATE ARE PHYSICAL CHANGES.


BIG IDEA Matter has properties that can be changed by physical and chemical processes.

KEY CONCEPT Changes of state are physical changes.

Vocabularymelting process by which a solid becomes a liquidmelting point temperature at which a substance meltsfreezing process by which a liquid becomes a solidfreezing point temperature at which a liquid becomes a solid; same as melting pointevaporation process by which a liquid becomes a gassublimation process by which a solid changes directly to a gasboiling process by which a liquid becomes a gas and produces bubblesboiling point temperature at which a liquid boilscondensation process by which a gas changes state to become a liquid

Review 1. For each sentence, circle the word that completes the sentence correctly.

Chemical changes (produce/do not produce) new substances.

Physical changes (produce/do not produce) new substances.

Take NotesI. Matter can change from one state to another. (p. 50)

II. Solids can become liquids, and liquids can become solids. (p. 51)

2. Give two examples of liquids that can change to solids.

A–B. Melting and Freezing (pp. 51–52)

3. Fill in the word triangle diagrams for melting and freezing.

melting:

The ice cream was melting.

freezing:

The ice cream was freezing.

SECTION

2.2

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4. What happens when the temperature of a solid reaches its melting point? What happens when the temperature of a liquid reaches its freezing point?

III. Liquids can become gases, and gases can become liquids. (p. 53)

5. Fill in the main-idea web for gases and liquids.

Liquids can become gases, and gasescan become liquids.

Evaporation occurs

________________________.

Boiling also results in

________________________.

Condensation occurs

________________________.

A–B. Evaporation, Boiling, and Condensation (pp. 53–55)

6. How are boiling, evaporation, and sublimation the same?

7. Below each picture, write evaporation, condensation, boiling, or melting.

A. B. C. D.

096-099-span-urb-a0202-rsg 97 3/11/04, 8:32:33 AM

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The Behavior of Matter

The following activity will allow you to observe the behavior of matter and help you to understand the following concepts: condensation, expansion, diffusion, evaporation, melting, and solidification. Demonstration #1- Place a drop of food coloring into very cold water and another drop into very hot water. Explain the difference in behavior.

• Cold Water -

• Hot Water - Demonstration #2 –Place one drop of alcohol on a heated hot plate or beaker. Explain what you observed. Demonstration #3 – Place ice water into a beaker. Breathe on the side of the beaker. Explain what you think the water molecules in your breath are doing. Demonstration #4 – Put on some hand sanitizer or lotion and walk around the room. What are the particles doing? Demonstration #5 – Observe a burning candle. What forms at the top of the candle? What happens after the flame is put out?

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Demonstration #6 – Place a balloon over a flask filled with some water. Place the flask over an open flame or hot plate. Describe what you see. Demonstration #7 – Ball and Ring Demonstration. Describe what you see. Why did this occur? Relate each term to an every day experience. Term Example condensation

evaporation

expansion

Melting

solidification

diffusion

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Lesson 8: Do Gases Have Mass? By the end of the last lesson, you probably decided that all the little bubbles that formed in the two reactions contained some kind of invisible gases. As the bubbles broke, the gases escaped to the surrounding air. If you knew for sure whether the gases have mass, then you would know how to make your predictions. How could you design an experiment that would test this out? Key Question: Do gases have mass? How can you find out? How does the mass of the starting substances compare to the mass of the ending substances when gases are formed and given off in a reaction? Open System

• This demonstration is done first as an “open system”—that is, the stopper /

balloon is left off the container. The Alka-Seltzer is fizzing in an open container. 1. Write your prediction about mass change—increase, decrease, or

remain the same—for this reaction. Also, be sure to write a reason for your prediction.

• Your teacher will prepare the apparatus for a class demonstration.

Mass Before Mass After

2. Does the experiment support your prediction? Any new thoughts about what happened to mass? Share your ideas with your group.

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Closed System • Now you teacher will repeat the demonstration as a “closed system.” When

there’s a top on a container, so that nothing can get in or out, it is called a “closed system.” The Alka-Seltzer will be fizzing in a closed jar.

3. Write your prediction about mass change— increase, decrease, or remain the same—for this demonstration and the reason for your prediction.

• Your teacher will now prepare the experiment as described above, but this

time the container will be secure.

Mass Before Mass After

4. What do you think will happen to the mass when the stopper / balloon is

taken off? Write your prediction and the reason for your prediction.

5. Now, remove the stopper / balloon. What happens? Why?

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Lesson 8: Do Gases Have Mass Think & Write Questions

1. Does the experiment support your prediction for the open system reaction? 2. Does the experiment support your prediction for the closed system reaction? 3. Try to explain what happened to cause the mass change in the open system. 4. Try to explain what happened which prevented a change in mass in the

closed system. 5. Try to explain what happened when the bottle cap was opened.

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6. What did you learn? Do gases have mass or not? What evidence do you have?

7. The reactants are ALL the substances you started with including any invisible

gases, and the products are ALL the substances that were formed, including any invisible gases. Are they different in an open system than they are in a closed system?

8. And now the big question, the one you’ve been trying to answer all along:

How does the mass of the products compare to the mass of the reactants?

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Lesson 9: Rusting Metal and the Deflating Balloon You learned in the last two lessons that chemical reactions sometimes produce invisible gases. The gases often make bubbles if they are produced inside a liquid. When the bubbles pop, the gases fly off into the atmosphere. Key Question: Can invisible substances like oxygen and other gases be involved in chemical reactions in any other way (not just as products)? Here is an activity to start you thinking about these questions. Steel Wool & Vinegar

• Obtain a piece of steel wool that will form a ball about the size of a ping-pong ball.

• Dip it in vinegar very briefly just to clean off the protective coating. • Dry it very thoroughly by pressing it between several layers of paper towel. • Pull the strands apart to loosen them and then drop the steel wool into a

clean flask. • Squeeze all the air out of a balloon and then stretch this deflated balloon

over the top of the Erlenmeyer flask. • Observe for a few minutes and then set it aside while you answer the

following question: 1. What are some very important properties of gases in addition to

the fact that they are usually invisible? Refer back to the last lesson if you need help on this answer.

• Now observe the reaction again. 2. What happened to the balloon in this experiment?

3. What is this evidence for?

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Funnel and Balloon

• Obtain a funnel and a beaker half filled with water, such

that the large end of the funnel will fit into it.

• Lower the funnel gradually into the beaker all the way to the bottom.

4. Does water enter the funnel? Why or why not?

• Now repeat the process, but this time hold your finger over the small end of

the funnel and immerse it into the beaker of water.

• Lower it gradually all the way to the bottom.

5. Does water enter the funnel? Why or why not?

• Now, with the funnel at the bottom of the beaker, remove your finger and observe what happens.

• Try this several more times by placing your finger over the end of the funnel when it is only partly immersed and see what happens.

• Place a balloon tightly over the small end of the funnel by first squeezing all

the air out of the balloon and then pulling it over the end of the funnel. Be careful not to rip the balloon.

• Place the large end of the funnel in the water. Lower it gradually.

6. What happens?

• Squeeze the balloon slowly but firmly and see what happens.

7. What is causing this to happen?

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Lesson 9: Rusting Metal and the Deflating Balloon Think & Write Questions

1. What invisible substance was in the funnel when you first placed it in the water? 2. When you placed your finger over the end of the funnel and pushed it into the

water, no water entered the funnel. How would you explain this? 3. How would you explain what happened when you removed your finger from

the funnel and water rushed in? 4. Why did the balloon inflate? 5. How can you explain your observations when you squeezed on the balloon?

This is a demonstration about air. It can push on water. Water can push on it. If you get some soda in a straw and blow on the straw, the soda flies across the

room. The air in your mouth pushed on the air in the straw, which pushed on the soda.

Air is a substance. You can’t see it, but it pushes on things.

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6. If you put a straw into a plastic bag filled with air, and started to suck the air out, what would happen to the plastic bag? Why?

Now look at your steel wool experiment. 7. Why was the balloon sucked into the flask when the steel wool rusted? 8. Did the air in the flask just disappear? Did it leak out? What happened to it?

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Lesson 10: Does Rusting Need Air? What happened to make the balloon get sucked into the beaker? Here is an activity that will help you figure out what happens with air and rusting. You will start by making a prediction.

A. Observe the flask with the steel wool reaction you saved from the last lesson. Make a prediction about what happened to the mass of the steel wool— increase, decrease or remain the same.

B. Write your prediction and the reasons why you think this happened. Once again, verifying your prediction is very tricky because—if there were any gases involved in the reaction— the mass of gases is very small. The procedure for reacting the steel wool must be changed slightly to make the steel wool react more, and therefore have a bigger change in mass that can be measured. This time the steel wool will be burned intensely with a lighter to cause a reaction that is very similar to rusting, only faster and more intense. More about that after you observe the reaction. • Your teacher will prepare a demonstration using a flame and enough steel

wool so that when compacted and rolled into a ball, it will be about the size of a ping-pong ball.

• Make a prediction about how the mass might change if the steel wool is

heated. Mass of Steel Wool Before

Heated Mass of Steel Wool After

Being Heated Difference

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Lesson 10: Does Rusting Need Air? Think & Write Questions

1. Write a description of the product. 2. What happened to the mass after the steel wool was burned? Did this surprise you? Did you expect something else? 3. Did the steel wool have something added to it or something taken away from it during the chemical reaction? 4. What, besides the steel wool, do you think might be involved in the reaction? 5. Remember, this reaction is similar to that of the rusting of steel wool. The same reactants are needed, and very similar products are formed. Can you now explain what happened with the steel wool rusting under the balloon?

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6. What do you think happened to the mass of steel wool when it rusted? Explain your answer using the data you collected in the experiment with the balloon: the observation that the balloon was sucked in to the beaker (what does this mean about the air around the steel wool?). 7. Why might your little brother think that matter was created in this experiment?

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Lesson 12: What Makes One Substance Different From Another?

Key Question: What makes substances different even though sometimes they may look alike? Think about this last question for a minute. What are some differences between vinegar and water? What are some differences between baking soda and sugar? Between hydrogen gas and oxygen gas?

? ? ? ? ? ? The basic difference between substances, one that chemists have figured out over the last several centuries, is that different substances are made up of different kinds of molecules. 1. Write what you remember about molecules. Chemists have come to understand that common substances in our environment—really all substances, common or not—when they are magnified millions of times, are composed of different kinds of molecules. Water, for example, has its own kind of molecule, which we often refer to as H2O.

a water molecule Sugar has its own kind of molecule. Vinegar is made up of its own special kind of molecule. Oxygen is made up of still another kind of molecule. Carbon dioxide is composed of molecules different from oxygen. So are aluminum, and iron, and copper, gold and many, many, many other solids, liquids and gases. Take a chunk of ice. Magnify it millions of times, and you would see water molecules joined together into sort of a cage-like structure, jiggling a little, but

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staying in the same place. Solids are made of molecules that are close together in neat, orderly, regular arrangements. When ice gets warmer, it becomes liquid water. The molecules jiggle faster as the ice gets warmer, until they break free from the forces that hold them together as solids. As a liquid, the molecules are moving freely within the container, sliding around past each other. But nothing about the individual molecules has changed. They are still H2O.

When water is heated, it boils and becomes water vapor. The molecules are given increased speed by the heat, and fly off the surface of the water, into the air. As gaseous water vapor, molecules are very far apart. But they are still H2O molecules. Whether a substance is in the solid, liquid or gaseous phase has only to do with how the molecules are arranged and how they move. If you heat a solid, it changes to a liquid and, if you heat it more, the liquid changes to a gas. The opposite is also true. If you cool a gas, it changes to a liquid and, if you cool it more, the liquid becomes a solid. The molecules themselves are the

same in all three forms. They have simply gone into different arrangements because of the increased speed (when heated) or decreased speed (when cooled.) And because the molecules are still the same, no new substances are formed. 2. Draw a picture of what you think pure ice, water and water vapor would look like if magnified millions of times. 3. a. How could you get a solid to change to a liquid or a liquid to a gas? Give

an example of each.

b. How could you get a gas to change to a liquid or a liquid to a solid? Give an example of each.

c. Would your methods work for butter? For chocolate? for a metal such as aluminum? Explain.

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4. All the food we eat (fruits, vegetables, milk, juice, meat, bread, etc.) contains large amounts of water. If fresh fruits or vegetables are left around for a while, they begin to wither and dry out. What kind of change is this? Use molecules to explain why you think this. 5. When an egg white is cooked, it goes from sort of a liquid to some sort of a solid. Is this a change of state or some other kind of change? (This is really a tough one, so here’s a hint. If water changes from liquid water to solid ice, do you heat it or cool it? When the egg white changes from liquid to solid, do you heat it or cool it?) Different Kinds of Molecules A gold ring can be melted into liquid gold, and then poured into a mold to make a new ring. Its gold molecules never change in this process. But if you poured water into the ring mold, and froze it, would it come out as gold metal? Why not? Every pure substance has its own special kind of molecule, different from the molecules of all other substances. How might a vinegar molecule be different from a water molecule? How might a salt molecule be different from a sugar molecule? Brainstorm answers to these questions, and write them on the board. Then work through the following questions. They help explain how there can be so many different kinds of molecules in the world. 6. a. Think of all the letters of the alphabet. How many letters are there?

b. What can you build out of letters? c. How many words can you build from the 26 letters of the alphabet? d. Where could you find a complete list of all these words? e. Are new words ever added to these lists?

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LETTERS MAKE WORDS

ESNESNON EKAM OSLA SRETTEL

7. a. Do all combinations of letters make words?

b. Does it make a difference what order the letters are in? c. Does it make a difference if you add or take letters away? d. Think of an example that will illustrate each of these last 3 questions.

Atoms Nature uses atoms as pieces to build hundreds of thousands of different substances—much like the 26 letters of the alphabet are used to build hundreds of thousands of different words. Many of these atoms are familiar to you. Others have very strange names. The chart lists the most common atoms.

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Think about how letters make words and use this information to answer the following questions. 8. How can all the different materials of the earth be made from only about 20 building blocks? 9. Where do you think you could find a complete list of all the different kinds of molecules? 10. Do all combinations of atoms make real molecules? 11. Does it make a difference what order the atoms are in when they form molecules? 12. Would it make a difference if you add atoms to a molecule or take them away? Like with words, where not all combinations of letters make a real word, not all combinations of atoms make real molecules. When atoms join together to form molecules, they must fit together, much like particular legs fit on certain chairs. Not all legs fit on all chairs; you must get the right leg to fit a given chair. In the same way, you must have the right atoms to fit together to make a certain molecule. You may have noticed that we are using a lot of models to talk about atoms and molecules. Why? Because atoms and molecules are so small that we cannot see them even under the most powerful microscope. So scientists use things we can see to help them understand how the things that we cannot see work. No model is ever perfect, so when using models it is important to think about how the model is similar to and how it is different from what it represents. Now it’s your turn to be a scientist and think of a good model for atoms and molecules.

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Try This:

• Consider bricks as a model for how atoms make molecules. List three things that can be built from bricks.

• Use the chart below to think about ways that objects made from bricks are

like molecules, and ways that they are different. Circle the correct answers when necessary.

Br icksBricks MoleculesMolecules

A house is made out of smaller pieces called bricks.

Molecules are made out of smaller pieces called __________.

Bricks can be used to make many different objects, including__________.

Atoms can be used to make many different molecules, including _______________.

A house is made of only one kind of building block (the brick.)

Most molecules are made of: a) only one kind of atom, or b) different kinds of atoms.

If someone adds bricks to the house (to build an addition) it is not the same house as it was before

If somehow one or more atoms is added to a molecule, it is: a) just a larger molecule of the same substance, or b) a totally new and different molecule making a new substance.

13. Write a list of at least ten things in your classroom that are made of molecules. 14. Write a list of at least ten things in your classroom that are made of atoms. 15. What’s the difference in these two lists? What’s the similarity? Explain. 16. Is sand made of molecules? Is each sand grain a molecule? Why do you think what you said?

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17. Is clay made of molecules? Why do you say that? 18. Is soup made of molecules? 19. How could you explain how soup is made of molecules? Fill in the blanks below, putting the letter for the correct part on the line.

a. broth, vegetables, rice, maybe meat b. proteins, and proteins are molecules c. cell parts, like a nucleus, mitochondria, cytoplasm d. animal and plant cells

Soup is made of

1. __________… which are made of: 2. __________ … which are made of: 3. __________ … which are made of: 4. __________ … and molecules are made of: 5. __________

In the next several lessons, you will build models of the substances involved in some of the reactions you have done.

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Let It Snow!

Law of Conservation of Matter: States that energy/matter cannot be created or destroyed, but can change its form. What you start with, you end with.

Mass of Plate ____________

Mass of Powder & Beaker ____________

Mass of Water & Beaker ____________

Total Mass of Reactants ____________

Total Mass of Products ____________

Procedure:

1. Fill the empty 50 mL beaker with 50 mL of water. 2. Separately find the mass of the plate, the beaker with the powder, and the

beaker with the water. 3. Add up the three masses and record in the “Total Mass of Reactants”

space. 4. Double-check the masses by putting them all on the scale together. 5. The handler should put his/her gloves on. 6. The handler should pour the water into the small beaker with the powder. 7. Put the empty beaker back on the scale. 8. Watch the reaction occur. 9. Record the “Total Mass of Products.”

Analysis:

1. How does the PolySnow Demonstration illustrate the Law of Conservation of Matter?

2. Do you think this is a physical or chemical reaction? Why?

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Lesson 13: Atoms In, Atoms Out Decomposing Water

Key Question: How can atoms and molecules be used to explain the formation of new substances? How can they be used to explain the Law of Conservation of Matter? A battery can be used to make bubbles appear under water. The water level went down as the bubbles were formed. How can atoms and molecules be used to explain the formation of bubbles from water? Decomposing Water

1. Write the common name of the reactant (the starting substance) on the data chart below.

2. You probably know the chemical formula for water. Write it on the chart.

The formula for any substance is the shorthand way that chemists use to show the kind and number of atoms that are needed to make a molecule of that substance. Can you figure out what the formula for water means? The H stands for hydrogen, and there are 2 atoms of hydrogen in a molecule of water. The O stands for oxygen, and since there are no numbers beside it, there is only 1 atom of oxygen in the water molecule.

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Now think about the products that were formed. What could they be? They were bubbles, of course, but what was in the bubbles? Since the water level went down, we might assume that the water changed into the bubbles. We know, though, that the water wasn’t boiling, because it never got hot. So the bubbles couldn’t have been water vapor. What else could they be? Here’s a hint. Look at the types of atoms that make up a water molecule. Since water molecules are made up of only hydrogen and oxygen atoms, the substances formed inside the bubbles can only contain hydrogen and oxygen. Would it be possible to have carbon dioxide (CO2) as a product of this reaction? Why? So what substances are inside the bubbles? Did someone say “Maybe there’s oxygen gas inside some of the bubbles, and hydrogen gas in the other bubbles?” Yes! The water molecule is coming apart and making hydrogen and oxygen molecules. Hydrogen gas is in the bubbles coming off one of the pencil leads, and oxygen gas is in the bubbles coming off the other lead. You can prove this by collecting the gases and conducting tests on them. The tests are easy. Hydrogen explodes with a loud pop when a burning piece of wood is placed in it. Oxygen makes a slightly burning (glowing) piece of wood burn very brightly. You need to collect these gases separately before you can test them.

3. On your chart, write the common name of the ending substances (the products.) In this case, they are oxygen gas and hydrogen gas.

4. Obtain a model-building kit and find the necessary pieces to build a water

molecule.

5. Your teacher will tell you which colors represent which kinds of atoms. Try making a model of a water molecule. You need two hydrogen atoms (the same color) and one oxygen atom (a different color).

Answer: Do all the models in the class look exactly alike? Why not? Chemists have found that both hydrogens attach on opposite sides of the oxygen, not to each other, like in the picture on the left. If your model has the two H hydrogens attached to each other, change it. Make two water molecules.

6. Draw a picture of your model of the water molecule on your data chart. 7. Label each atom or color it to show what kind they are.

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8. Now build models of the ending substances. Start with oxygen.

Are you wondering what the formula is? Chemists found—a long time ago—that two oxygen atoms join together to make an oxygen molecule, so what would the formula be?

9. Write the formula in the proper space. Then make the model. Remember to use the same color that you used above for oxygen.

10. Draw a picture of your model of the oxygen molecule on your data chart.

11. Label each atom or color it to show what kind they are. Remember to use the same color that you used above for oxygen.

12. Now try making a model of a hydrogen molecule.

Like oxygen, two atoms of hydrogen join together to make a hydrogen molecule.

13. Write the formula in the proper space.

14. Draw a picture of your model of the hydrogen molecule on your data chart.

15. Label each atom or color it to show what kind they are. Remember to use

the same color that you used above for hydrogen. Now that you know the formula and can make a model of each reactant and each product, you are ready to figure out how new substances form. Recall from the last lesson what makes one substance different from another: Each substance is made up of its own kind of molecule, made of different kinds of atoms. Water is a collection of water molecules, each molecule made from 2 hydrogen and 1 oxygen atoms. Vinegar is a collection of vinegar molecules, each molecule made from 2 carbon atoms, 4 hydrogen atoms, and 2 oxygen atoms. Sugar is made of sugar molecules, each molecule made from 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. What happens when an electric current runs through water, and the water decomposes into hydrogen gas and oxygen gas? The atoms of the water molecules come apart and then form into new molecules. No new atoms of any kind are added. Its like taking a Lego building apart and using all the pieces to make two smaller objects, like a plane and a tree.

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Let’s try doing this with your models. Take a molecule of water apart and USE THESE SAME ATOMS to make the products, in this case, oxygen and hydrogen molecules.

What happens? You can make the hydrogen molecule (H2), but you cannot make the oxygen molecule (O2), because you have only one oxygen atom. Where can the other oxygen atom come from to make an oxygen molecule? In the real chemical reaction you watched, with many bubbles being formed, there were billions and billions of molecules. Billions of water molecules were coming apart at the same time. And all the other water molecules coming apart also have an oxygen atom. So two oxygen atoms from different water molecules find each other and join together to form an oxygen molecule. Try doing that with your models now.

16. Take a second molecule of water apart and make another hydrogen molecule.

17. Use this single oxygen atom to join the oxygen atom from the first water

molecule. Together they form an oxygen molecule.

How many water molecules did you use in all? 18. Draw exactly that many water molecules in the space on your data sheet

labeled PICTURES OF MODELS FOR THE REACTION. 19. Color your models using the same color code as above.

How many hydrogen molecules were formed?

20. Draw exactly that many hydrogen molecules in the appropriate space on your data sheet.

21. Color your models using the same color code as above.

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How many oxygen molecules were formed?

22. Draw exactly that many oxygen molecules in the appropriate space on your data sheet.

23. Color your models using the same color code as above.

Are you beginning to see how atoms rearrange themselves to make new substances? Conservation of Matter Now let’s see how atoms and molecules can be used to explain conservation of matter. Remember that conservation of matter in chemical reactions means that the beginning mass of all of the reactants is exactly the same as the ending mass of all of the products. Can you speculate about why this might be? ? ? ? ? ?

24. How many atoms of oxygen are there in the molecules of the reactant—the starting substance? How many atoms of hydrogen are there in the molecules of the reactant? Record this information on your data sheet under ACCOUNTING FOR ATOMS.

25. How many oxygen atoms are there in the product molecules—the ending

substances? How many hydrogen atoms are there in the product molecules? Record this information on your data sheet in the appropriate space.

WHAT DO YOU NOTICE ABOUT THE NUMBERS OF ATOMS IN THE STARTING SUBSTANCES AND THE ENDING SUBSTANCES? They are the same! The atoms don’t disappear or appear out of nowhere… they just rearrange themselves into new molecules. And if each atom has a certain mass (which it does), then how does the mass of the reactant compare with the mass of the products? This is the Law of Conservation of Matter, or the Law of Conservation of Mass. No mass is lost or gained in chemical reactions. No mass is lost or gained. No matter is lost or gained. Why? Because no atoms are lost or gained during chemical reactions.

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Chemical Equations Chemists use a shorthand to write about this reaction. They show the starting substances on one side of an equation, and the ending substances on the other side, to show how their masss are equal. They use an arrow instead of an equal sign, to show that the left side reactants change into the right side products. The formula for this reaction is 2 H2O ➜ 2 H2 + O2 The 2 in front of the H2O means that two molecules of water were used in the reaction. The 2 in front of the H2 means that two molecules of hydrogen gas were formed. No number in front of the O2 means that one molecules of oxygen gas was formed.

26. Write the formula for this reaction on your chart.

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Lesson 13: Atoms In, Atoms Out Decomposing Water Think & Write Questions

1. When water boils a gas leaves its surface, and the level of the water

goes down. When water is chemically decomposed, like in this experiment, it forms gas and the level of the water also goes down. What’s the difference between boiling and decomposing water?

2. Could chlorine gas, Cl2 be a product in this reaction? What about carbon dioxide CO2? Explain why you think this.

3. Do you think it would be possible for ozone, O3 to form as a product in this reaction? What about hydrogen peroxide, H202? Explain why you think this.

4. Explain the difference between the two number 2’s in the 2H20 model. Use your models to help you.

5. After doing this same experiment with water that you just completed,

and doing it until all the water was gone, the teacher asked what happened to the water. Jamie responded quickly with, “Oh, that’s easy. It just decomposed into nothing.” You are now an expert at this. How would you help Jamie understand what happened?

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Lesson 14: Atoms In, Atoms Out Rusting

Let’s repeat the whole process now with a different chemical reaction: rusting. Take a minute or two to remember what a fresh piece of steel wool and a piece that has reacted (perhaps the one with the balloon on top) look like.

__ Fe + __ O2 ➜ __ Fe2O3

1. You have a friend who doesn’t know the first thing about chemistry. He thinks rust just starts somehow and then “eats” away at cars or pipes – sort of like termites eat wood – and this makes holes in the car or in the pipe. You must explain to him what is really going on. Tell him what the reactants are and where they come from. Explain what product is formed and how this happens.

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2. Is rust just the same thing as iron, only brown? Explain.

3. A friend of yours says that she left a shovel outside during the winter and it got rusty. She says that if you scrape off the rust with a steel brush, the shovel will be as good as new. To test her knowledge of chemical reactions, you ask her if it will mass the same after the rust is scraped off as when she bought it. She says she’s not sure – but it seems like it should –after all, rust just grows on the shovel like moss on a tree or mold on stale bread. Do you agree? Explain. Use atoms and molecules in your explanation.

4. Some cars and trucks get so rusty that holes start to form in the metal. How does this happen?

5. Give some examples of how we protect things made of iron and keep them from rusting. Then explain how the protection works.

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Balance these Equations!! Make sure to account for the atoms on both sides of the reaction. Remember, the atoms on the reactant side must equal the atoms on the product side. Fill in the blanks with the correct co-efficient!

1. 4Si + _____ S8 → 2Si2S4

Si = Si =

S = S =

2. ______P + 5O2 → 2P2O5

P = P =

O = O =

3. Si + _____F2 → SiF4

Si = Si =

F = F =

4. ______C2H6 + 7O2 → 6H2O + 4CO2

C = C =

H = H =

O = O =

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5. PCl5 + 4H2O → _______H3PO4 + 5HCl

P = P =

Cl = Cl =

H = H =

O = O =

6. ______Ca + N2 → Ca3N2

Ca = Ca =

N = N =

7. SO3 + ______H2O → H2SO4

S = S =

O = O =

H = H =

8. C6H4Cl2 + ______O2 → 6CO2 + ______H2O + Cl2

C = C =

H = H =

Cl = Cl =

O = O =

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9. 2C4H10O2 + _____O2 → 8CO2 + 10H2O

C = C =

H = H =

O = O =

10. 3Ca + _____DyF3 → _____Dy + 3CaF2

Ca = Ca =

Dy = Dy =

F = F =

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Part Two: Density & Volume

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Calculating Volume Lab In today’s lab you will learn three different methods to calculate volume. Method 1 – L x W x H Method 2 – Overflow Method Method 3 - Displacement Station #1:

• You will be calculating volume using the L x W x H method. Record your data below. What is the volume of each object at that station?

Object Description Volume

Station #2:

• You will be calculating volume using the overflow method. Record your data below. What is the volume of each object at that station?


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Station #3: • You will calculate volume using the displacement method. Record your

data below. What is the volume of each object at that station?


Station #4:

• You will answer the following questions:

1. What makes up the mass of an object?

2. What does the term volume mean to you?

3. What makes one object more dense than another?

4. How can we change the density of an object?

5. If density changes, would you notice a change in mass and volume?

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Identifying Substances Based on Their Densities

PURPOSE: To identify substances based on their densities. PROCEDURE:

1. Select a block and write a brief physical description of it in the data table below.

2. Mass the block and record its mass in the data table below. 3. Calculate its volume (L x W x H) and record the volume in the data table

below. 4. Calculate the density using the following formula:

Density = Mass in grams (g) Volume in cubic centimeters (cm3)

5. Record the density of each block in the data table below. 6. Look at the table of known densities and decide the material from

which each block is composed. 7. Repeat steps 1-6 for remaining blocks.

RESULTS/DATA

Description Mass Volume Density Material grams cm3 g/cm3

grams cm3 g/cm3

grams cm3 g/cm3

grams cm3 g/cm3

grams cm3 g/cm3

grams cm3 g/cm3

grams cm3 g/cm3

grams cm3 g/cm3

grams cm3 g/cm3

grams cm3 g/cm3

Table of Known Densities:

:

Material Actual Density (g/cm3)

Calculated Density Range

Oak .70 0.6 - 0.95 Nylon 1.13 0.9 – 1.2 Pine .40 0.35 – 0.6 Rosewood 0.90 0.9 – 1.2 Poplar .35 0.35 – 0.5 PVC 1.35 1.35 – 1.65

Material Actual Density (g/cm3)

Calculated Density Range

Copper 8.9 8.85 – 9.3 Brass 8.0 8.4 – 8.9 Steel 7.6 7.6 – 8.5 Aluminum 2.7 2.7 – 3.1 Acrylic 1.2 1.15 – 1.3

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CONCLUSION QUESTIONS:

1. How would you define density?

2. Which material was the most dense?_______________ The least dense?_______________

3. How were the most-dense substances physically different from the least dense substances?

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Calculating the Density of Sand and Water

Goal- To create an experiment that will allow you to calculate the density of sand and water. Materials- Sand Water 2 Beakers Scale Procedure- Determine the best way to calculate the density of sand and water based on the materials you have. List the steps to your procedure in the space provided. Procedure- 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Data Table Sand Water Mass (g)

Volume (ml)

Density (g/ml)

Conclusion- Analyze your data and write a conclusion for it here. Create a graph of your results.

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Density / Mass / Volume Analysis:

1. What is density?

2. How do you calculate density?

3. What is the density of a piece of wood that has a mass of 25 grams and a volume of 5 cm3?

4. How can we change the density of an object?

5. What happens to the density of a bar of soap if I cut the bar in half?

6. You observe two beakers of water that have the same volume. One contains very hot water and the other contains very cold water. Use this information to answer the following questions:

a. What can be said about the mass of each beaker?

b. What can be said about the volume of each beaker?

c. What can be said about the density of each beaker?

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Part Three: Periodic Table of the

Elements

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CHEMICAL INTERACTIONS, CHAPTER 1, READING STUDY GUIDE A 13

ATOMS ARE THE SMALLEST FORM OF ELEMENTS.


BIG IDEA A substance’s atomic structure determines its physical and chemical properties.

KEY CONCEPT Atoms are the smallest form of elements.

Vocabularyproton a positively charged particle within an atomneutron an uncharged particle within an atomnucleus protons and neutrons together at an atom’s centerelectron a negatively charged particle moving around the outside of the nucleusatomic number the number of protons in the nucleus in an atomatomic mass number combined number of protons and neutrons in a nucleusisotope element that has the same number of protons, but a different number of neutrons from another atom of the same elemention an atom that has gained or lost electrons

ReviewIf the statement is true, write true. If it is false, replace the underlined wordto make it true.

1. Atoms are made of protons, neutrons, and isotopes. __________________ .

2. Each element has a unique atomic number. _________________________ .

Take NotesI. All matter is made of atoms. (p. 9)

3. About how many different elements make up everything on Earth?

A–B. Types of Atoms, Names and Symbols of Elements (p. 10)

4. All living things contain some common elements. Their symbols are given below. Write the name of each element next to its symbol.

O ____________ C ____________ N ____________ H ____________

Which one of these is the most common element in the universe?

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14 CHEMICAL INTERACTIONS, CHAPTER 1, READING STUDY GUIDE A

II. Each element is made of a different atom (p. 11)

A–B. The Structure of an Atom, Atomic and Atomic Mass Numbers (pp. 11–12)

5. What are the three particles that make up an atom?

6. What is the atomic number of an atom?

7. Atomic mass number is the sum of ____________ and ____________.What is an isotope?

III. Atoms form ions. (p. 14)

8. An ion is an atom that has a positive or negative charge. What happens when an atom becomes an ion?

A–B. Formation of Positive Ions and Formation of Negative Ions (pp. 14–15)

9. All aluminum atoms have 13 protons. Aluminum atoms often lose 3 electrons to form ions. Label the ion on the right side by noting the protons and electrons that remain.

13 electrons(13!)

aluminum atom (Al)

Loses 3electrons

13!

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ATOMS OF ELEMENTS MAKE UP THE PERIODIC TABLE.



KEY CONCEPT Atoms of elements make up the periodic table.

Vocabularyatomic mass average mass of all the element’s isotopesperiodic table the table that shows the repeating pattern of properties of the elementsgroup the elements in a column of the periodic tableperiod a horizontal row in the periodic table

Review 1. Fill in the concept map for atoms.

ATOMS

are made of

have a central

which

con

tains

around which orbit

Take NotesI. Elements can be organized by similarities. (p. 17)

2. The average mass of all an element’s isotopes is its ____________________.

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A. Mendeleev’s Periodic Table and Predicting New Elements (pp. 18–19)


Mendeleev producedthe first periodic table.

The elements in rows had similar .

.A periodic table shows

II. The periodic table organizes the atoms of the elements by properties and atomic number. (p. 19)

4. How is the modern periodic table organized?

A. Reading the Periodic Table (p. 19)

5. One square from the periodic table is shown below. Label each of the parts of this element’s square.

37

RbRubidium

85.468

A

B

C

D

A

B

C

D

6. How many protons does the element shown above have?

B. Groups and Periods (p. 22)

7. What are the vertical columns of the periodic table called?

8. What is the horizontal row called?

C. Trends in the Periodic Table (pp. 22–23)

9. How does atomic size change as you move down the periodic table?

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1

Investigation A1

Atom Building Game Copyright 2009 CPO Science Can be duplicated for classroom use

A1 Building AtomsWhat is an atom?

A What are the parts of an atom?The Atom Building Game represents a model of an atom. Thecenter of the board represents the nucleus of an atom. The outerrings around the center represent energy levels.

Three colors of marbles come with the game. The marblesrepresent the three kinds of subatomic particles in the atom. Thegreen marbles represent protons. The blue marbles representneutrons. Protons and neutrons always go in the nucleus of anatom. The yellow marbles represent electrons. Electrons alwaysgo in the energy levels.

Protons and electrons have charge. Charge can be positive ornegative. Each proton has a positive charge of +1. Each electronhas a negative charge of G1. Neutrons have no charge and are Ineutral.J

When the number of protons equals the number of electrons in an atom, theatom has no charge. An atom has a charge when the number of protons isdifferent from the number of electrons. An atom with a positive or negativecharge is called an ion.As you answer the questions, you will build a beryllium atom. When asked tofind the total charge for a group of subatomic particles, use the followingformula:

a. Place four protons (green marbles) in the center of the board. What is the total charge of the protons?

b. Place five neutrons (blue marbles) in the center of the board with the protons. What is the total charge of the protons plus the neutrons?

Atoms make up everything you see, touch, smell, and eat. Atoms are so small you can8t see them. It takes millions and millions of atoms to form a single crystal of salt in your salt shaker. Each type of atom is called an element. All the elements are represented on a special chart called the periodic table. In this investigation, you will use the Atom Building Game to learn the parts of an atom and what makes the atoms of one element different from the atoms of another element.

Materials! One Atom Building Game with

marbles.! Periodic table that comes with

the game

Number of particles Charge of one particle� Total charge=

83

2 Copyright 2009 CPO Science Can be duplicated for classroom use

c. If you have four electrons (yellow marbles), what is the total charge of these particles?

d. Finish building the atom, by adding the four electrons to the outer levels on the board. Now, add the total charges of all the particles in the atom. What is the total charge of the atom you built?

e. Draw a diagram of the beryllium atom. Include all the parts of the atom. Label your diagram.

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Investigation A1


B Identifying elementsOn the Atom Building Game board, you have a model of a beryllium atom. This atom has fourprotons, five neutrons, and four electrons. You can find out more information about berylliumby looking at the periodic table that comes with the Atom Building Game.

a. What is the symbol for the element beryllium?

b. What is the atomic number for beryllium?

The atomic number of an element is equal to the number of protons in the nucleus of an atom ofthe element. Since the atomic number of beryllium is 4, all beryllium atoms have 4 protons.

Fill in the Element Name and Atomic Number columns in the table below.

C Building atoms1. Use the atomic numbers for the elements to fill in the

Number of protons column in the table above.2. The number of electrons in an atom equals the number

of protons. Use this information to fill in the Number of electrons column in table above.

Element Name

Atomic Number

Number of protons

Number of electrons

Mass number

Number of neutrons

Hydrogen 1

Oxygen 16

11 23

13 27

Calcium 40

29 63

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3. The mass number for an atom is equal to the number of protons and neutrons in the nucleus. Atoms of an element can have different numbers of neutrons, but all atoms of an element have the same number of protons. The formula for mass number is:

4. Rearrange the formula for mass number so that it is a formula for figuring out the number of neutrons in an atom. Use this new formula and the mass numbers in the table above to fill in the Number of neutrons column.

D What are isotopes?Atoms of the same element that have different mass numbers are called isotopes. Hydrogenhas two isotopes. One has a mass number of I1K and is called hydrogen-1. The other has a massnumber of I2K and is called hydrogen-2.

a. How many neutrons does hydrogen-1 have? How many neutrons does hydrogen-2 have?

b. How many isotopes does magnesium have? Write the names of these isotopes.

c. How many neutrons does an atom of copper-65 have? How many protons does it have?

Number of protons Number of neutrons+ Mass number=

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Investigation A1


Assessment 1. Use the periodic table to fill the Atomic number and Number of protons columns for each

atom in the table. Use the numbers of protons and electrons to fill in the Total charge column. Then decide whether each atom is an ion.

2. The first two columns of the table below are partially filled in. Use the periodic table to help you fill in the other columns. Then fill in the Number of protons and Number of electrons. Use the mass number and number of protons to fill in the Number of neutrons column for each atom.

Element name Atomic number

Number of protons

Number of electrons

Total charge

Is the atom an ion?

hydrogen 0

lithium 2

beryllium 4

boron 2

oxygen 8

fluorine 10

Element name Atomic number

Number of protons

Number of electrons

Mass number

Number of neutrons

hydrogen 2

7 15

oxygen 18

13 27

silicon 28

phosphorus 31

53 127

xenon 124

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Extra space for notes:

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Investigation A2


A2 Atomic ChallengeWhat holds and atom together?

A What holds an atom together?One of the atomic forces that holds an atom together is called electromagnetic force. This forcefollows certain rules. The rules are explained below and illustrated in the diagram.

The rules for electromagnetic force are:

A Positive charges attract negative charges.

A Positive charges repel other positive charges.

A Negative charges repel other negative charges.

Electromagnetic force is responsible for holding the electrons inplace. The electrons are attracted to the protons in the nucleus ofthe atom.

a. Using the Atom Building Game, build a helium atom using two protons (green marbles), two neutrons (blue marbles), and two electrons (yellow marbles). Place the green and blue marbles close together in the nucleus of the board. Place the electrons in the first energy level (the nearest one to the nucleus). What is the total charge of the subatomic particles in the nucleus of this atom?

b. According to the rules for electromagnetic force, what should happen to these two protons in the nucleus when they are close together?

An atom(s structure includes a nucleus with protons and neutrons, and energy levels with electrons. Each of the protons has a positive charge. Each of the electrons has a negative charge. Positive charges and negative charges attract one another. The attractive atomic force between charges helps hold an atom together. In this investigation, you will learn more about the forces that hold an atom together. You will use your understanding of atomic structure to play a game called the Atomic Challenge.



the game

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B What keeps the nucleus from flying apart?Another atomic force that holds an atom together is called strong nuclear force. Strong nuclearforce holds the positively charged nucleus together. This force only works when the subatomicparticles are very close together. If the particles are too far apart, electromagnetic force takesover and causes the particles to repel each other. Here are the rules for strong nuclear force:

F Strong nuclear force holds protons and protons together when they are very close.

F Strong nuclear force holds neutrons and neutrons together when they are very close.

F Strong nuclear force holds protons and neutrons together when they are very close.

a. In the diagram below, why do you think there are more arrows representing strong nuclear force than there are representing electromagnetic force?

b. In your own words, describe how electromagnetic and strong nuclear forces hold an atom together.

C Introduction to the Atomic Challenge GameAtomic Challenge is a game that you will play using the Atom Building Game. To play thisgame you need to understand the information on the periodic table. Take some time now to goover the periodic table in your group. Work together until everyone understands the differencebetween the atomic number and the mass number for an atom, and the difference between an ionand an isotope.

Two more terms that you will need to understand are stable and neutral. The mass numbers ofall stable isotopes of the elements are listed on the periodic table. Neutral atoms have equalnumbers of protons and electrons.

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Investigation A2


For each of these terms, write a sentence that shows you understand its definition.

a. atomic number

b. mass number

c. ion

d. isotope

e. stable

f. neutral

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D Setting up1. Each Atom Building Game board can have four

players. Each player should use one of the four pockets at the corners.

2. Each player should start with the following marbles in their pocket:6 blue marbles (neutrons)5 green marbles (protons)5 yellow marbles (electrons)

3. The remaining marbles stay in the containers and are the Lbank.M Players may need to trade marbles with the bank later in the game.

E The game of Atomic ChallengeThe object of the game is to play all your marbles by adding them to the board to make neutral,stable atoms. The first player to run out of marbles wins. After each turn, you must identifythe atom you made. For example, after a play you might say Llithium sixM if the marbles youadded made an atom with 3 protons (green marbles), 3 neutrons (blue marbles), and 3electrons (yellow marbles).

Each player takes turns adding up to 5 marbles to the atom.Marbles must be added according to these rules for buildingatoms:

1. The number of protons matches the atomic number of the atom.Number of green marbles = Atomic number

2. The total number of protons and neutrons equals one of the mass numbers for that element. Green marbles + Blue marbles = Mass number

3. The number of electrons and protons match.Number of yellow marbles = Number of green marbles

4. Protons and neutrons go in the nucleus.Only green and blue marbles in the center of the board.

5. Electrons go in the energy levels.Only yellow marbles in the energy levels.

Example move: In the graphic above, lithium-7, with 3 protons, 4 neutrons, and 3 electrons,is represented on the Atom Building Game board. If 1 proton (green marble), 1 blue marble(neutron), and 1 electron (yellow marble) are added, the atom becomes beryllium-9. Berylliumhas 4 protons, 5 neutrons, and 4 electrons.

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Investigation A2


F Additional rules1. You can add no more than 5 marbles per turn. The 5 marbles can include any

mix of colors, such as 2 green, 1 blue, and 2 yellow. You may not always be able to add 5 marbles; sometimes you will only be able to add 3 or 4 and still make a real atom.

2. You can challenge a move. After each playerIs turn, look at the periodic table that comes with the Atom Building Game to see whether the atom is correct or not. If the atom has been incorrectly built or identified, you can challenge the move. A player that makes an atom incorrectly during his or her turn must take the marbles back and does not get to try again until the next turn. The next player then takes a turn.

3. A player can trade marbles with the bank INSTEAD of taking his or her turn. You can take as many marbles, and of as many colors, as you need, but you must take at least as many total marbles as you put in. For example you can trade 2 yellows for 1 yellow, 1 blue, and 1 green. You can put in 2 and take 3, but you cannot put in 2 and take only 1 back.

After you have completed a game of Atomic Challenge, answer the following questions.

G What did you learn? a. What atomic force keeps electrons in place around the nucleus of an atom?

b. What atomic force holds the nucleus of an atom together? Why is this force necessary?

c. What is the atomic number of sodium?

d. How many protons does sodium have?

e. How many isotopes does calcium have?

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f. What is the mass number of beryllium?

g. What is the charge on a bromine atom that has 35 protons and 36 electrons?

h. What do you call an atom that has a positive or a negative charge?

i. What does it mean when an atom is stable and neutral?

j. The Atom Building Game is a model of an atom. In your own words, define the term Jmodel.K Include in your answer why models are useful.

k. Describe three ways in which the Atom Building Game is like a real atom and three ways it is not.

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Investigation A2


Assessment 1. An Atom Building Game has 16 green marbles, 16 blue marbles, and 18 yellow

marbles. Answer the following questions based on this information. a. What atom is represented on the Atom Building Game board?

b. What is the total charge of this atom?

c. What would you need to do to make this atom neutral?

2. Atoms of an element can have more than one mass number, but only one atomic number. Why?

3. What is the difference between a stable atom and a neutral atom? Can an atom be both stable and neutral?

4. Why is the periodic table of the elements an important tool in science? Come up with as many reasons as you can to explain why the periodic table is so useful.

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Investigation A3


A3 Building MoleculesWhat is a molecule?

A What is a compound?Materials you use can be either elements or compounds. Elements are made of only one kind of

atom. Gold is an example of an element. A piece of pure gold contains billions of gold atoms

and no other types of atoms.

Compounds are made of two or more kinds of atoms. Table salt an example of a compound. The

smallest particle of salt that exists is called a molecule. Each grain of salt in your salt shaker

contains billions of salt molecules. Each salt molecule contains one sodium (Na) atom and one

chlorine (Cl) atom. Another name for table salt is sodium chloride, which can be abbreviated

NaCl.

Use the above information to complete the table below.

When atoms combine with other atoms, they form molecules. The number of electrons in the outermost energy level is important to understanding why atoms, like hydrogen and oxygen, combine to form molecules. Hydrogen and oxygen atoms combine to form water molecules.



the game

Common name of material

What atoms are in the material? Is the material an element or a compound?

salt sodium (Na) and chlorine (Cl) compound

diamond carbon (C)

silver silver (Ag)

sugar carbon (C), hydrogen (H), oxygen (O)

iron iron (Fe)

rust iron (Fe) and oxygen (O)

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B Outermost energy levelsThe reason atoms combine with other atomsto make compounds has to do with theelectrons in the outermost energy level. Theoutermost energy level is the one farthestfrom the nucleus of the atom.

Use the Atom Building Game to build a neon-20 atom. When you add electrons (yellowmarbles) to an atom, fill the energy levelclosest to the nucleus first before filling thenext energy level.

a. How many electrons are in the outermost energy level of your neon-20 atom?

b. Are there any empty spaces in the outermost energy level of the neon-20 atom?

c. Do you think a neon atom would combine with another atom to form a compound? Why or why not?

C Combining atomsFor this part of the investigation, your group will pair up with another group in your class.When you have paired up, decide which group will build a sodium-23 atom and which willbuild a chlorine-35 atom. After you have built these atoms, place them close together andanswer the questions below.

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Investigation A3


a. How many electrons does sodium have in its outermost level? How many empty spaces

does it have in its outermost level?

b. How many electrons does chlorine have in its outermost level? How many empty spaces

does it have in its outermost level?

c. Sodium and chlorine combine to form a compound known as sodium chloride. You know

this compound as Ctable salt.D Why do you think these two atoms tend to combine with

each other?

D What is a chemical bond?When two atoms combine their electrons to fill the outermost energy level, we say that they

have formed a chemical bond. A group of atoms connected by bonds is called a molecule. In part

3, you made a molecule with only two atoms. Molecules can also be made of more than two

atoms. For the next exercise, you will need to work with other groups in your class to make a

water molecule using Atom Building Game boards. Water molecules contain one oxygen atom

and some hydrogen atoms.

a. Make oxygen-16 with your Atom Building Game board. How many hydrogen atoms will

you need to complete the outermost energy level of the oxygen?

b. Once you have figured out how many hydrogen atoms you need, get together with the

same number of groups in your class. With the other groups, place the boards together to

make the water molecule.

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c. Do you think water is an element or a compound? Explain your answer.

d. Complete the chemical formula for water (see diagram to the right).

Write the number of hydrogen atoms in a water molecule in the blank

next to the symbol for hydrogen (H).

e. What does a chemical formula tell you about a compound?

f. In the case of the neon-20 atom, the molecule of sodium chloride, and the molecule of

water, how many electrons, in total, were in the outermost energy levels? Why do you

think atoms combine with other atoms?

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Investigation A3


Assessment 1. Explain the difference between an element and a compound. Give one example of

each.

2. Sodium and chlorine combine to form a molecule of table salt. a. Why are sodium and chlorine a good match for making a molecule?

b. Fluorine has the same number of electrons in its outermost energy level as sodium. How many sodium atoms do you think will combine with fluorine? Explain your reasoning.

3. Which one of the three different subatomic particles in an atom is involved in forming bonds between atoms? Why do you think the other two kinds of subatomic particles are not involved in forming bonds?

4. Look at the periodic table. The last column (group 18) contains a group of elements called the Mnoble gases.N The atoms of these elements do not combine with other atoms to form compounds. a. How many electrons do you think atoms of the noble gases have in their

outermost energy levels?

b. Explain why noble gases do not combine with other atoms to make compounds.

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THE PERIODIC TABLE IS A MAP OF THE ELEMENTS.



KEY CONCEPT The periodic table is a map of the elements.

Vocabularyreactive how likely an element is to undergo a chemical changemetals elements that conduct electricity, are shiny, and heat wellnonmetals elements with properties the opposite of metalsmetalloids elements with properties between metals and nonmetalsradioactivity the process where atoms release particles and produce energy half-life the amount of time it takes for half of the atoms in a set amount of a substance to decay

Review 1. Look at this column from the periodic table below. What properties are most

likely similar among these elements? Explain why.

27

CoCobalt58.933

9

45

RhRhodium102.906

77

IrIridium192.217

109

MtMeitnerium

(268)

Take NotesI. The periodic table has distinct regions. (p. 26)

2. The periodic table is divided into three regions—nonmetals, metals, and metalloids. Label these regions on the diagram below.

1.

2.

3.

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3. Some elements are more reactive than others. Which groups on the periodic contains the elements that are most reactive?

II. Most elements are metals. (p. 27)

4. Name four characteristics of metals.

A–B. Reactive Metals, Transition Metals, and Rare Earth Elements (pp. 27–28)

5. Why are sodium and potassium often stored in oil?

6. Name two uses for transition metals.

III. Nonmetals and metalloids have a wide range of properties. (p. 29)

7. List three examples of nonmetals.

8. What is a common use for metalloids?

IV. Some atoms can change their identity. (p. 30)


Some atoms can changetheir identity.

An element's identity depends on the number of protons it has.

Radioactivity is a process where______________________________________.

The stability of the nucleus ___________________________________________________.

An isotope is radioactive if ___________________________________________________.

A–B. Uses of Radioactivity in Medicine and Radioactive Decay (pp. 31–32)

10. What is one way radioactivity is used in medicine?

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Element Poster ProjectElement Poster Project Objective: You will have the opportunity to research and become an expert on one of the elements on the periodic table. This information will be presented on a poster. Your poster must include the following:

• Name of the element • Symbol • Atomic Number • Who? Where? When was it discovered? • A poem or a pun related to your element • A list of common uses (minimum of three) • Find some bizarre fact about your element - something you believe is

unique and relatively unknown by the general population. • A picture of the element, or a picture related to one of the element’s uses.

On the back of your poster:

• Choose five (5) additional elements. • List the element names and give two (2) common uses of each element.

Guidelines

• Maximum of two students per project • You will be given one day to complete your research using the Internet in

class. o During this time, you will begin to put your project together: discover

information, create poem or pun, and find uses and pictures. • You will be given two additional days of class-time to work on your poster. • Make it colorful and interesting. Use pictures, objects, drawings, diagrams,

etc. anything to appropriately draw attention to it. • Be original and creative. These projects are intended to educate and

entertain and be displayed for several semesters. • Neatly display your name(s) and class period on bottom-right, front corner

of the poster.

Suggested Websites:

• Web Elements: www.webelements.com • It’s Elemental: http://education.jlab.org/itselemental/ • Los Alamos National Lab: http://periodic.lanl.gov/default.htm • Royal Chemical Society Visual Elements:

http://www.chemsoc.org/viselements/ • Chem4Kids: http://www.chem4kids.com/files/elem_intro.html • Chemical Elements: www.chemicalelements.com • Chemicool: www.chemicool.com • Elements: http://dmoz.org/Science/Chemistry/Elements/

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Chemistry Notes

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Chemistry Notes

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Chemistry Notes

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Chemistry Notes

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Chemistry Notes

Documents

Chemistry - School District of Haverford Township · 3 T. Trimpe 2000 Name_____ Metric Conversions Fill in the boxes in the stair step diagram. Try these conversions, using the ladder