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Unit IV “Mixtures” and Unit V “Matter”

Topics for “Mixtures” and “Matter” Reference Chapter 2 in your textbook

Mixing it up With Mixtures

(2-5) Definition and properties of mixtures (how they differ from elements and compounds)

(2-5) Homogeneous vs. Heterogeneous mixtures

(2-5) Separating mixtures by different physical means

Everything Does “Matter” (This is mostly a review!)

(2-3) Definition and properties of matter in general

(2-3) The three most studied states of matter (there are actually five!)

(2-3) Properties each of the three commonly studied states of matter.

(2-3) The relationship between energy and states of matter

(2-3) The Law of Conservation of Matter

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Chem-is-try Name __________________________________Hour _____

Paradigm Lab (Mixtures): “Separate This!” “There are not more than five primary colors (blue, yellow, red, white, and black), yet in combination they produce more hues than can ever been seen” -Anonymous

Introduction:

Most substances that we come in contact with every day are mixtures. Look at the

ingredient list of any of the food you eat or the personal care product you use. The

purpose of this experiment is to study the physical properties of dyes, salt, sand and

iron and use this information to design and carry out a procedure to separate a

mixture of these substances. The mass percent composition of the mixture can be

calculated from the masses of the recovered components. Now that you have

completed the Physical and Chemical Change lab, you should now have the skills to separate homogeneous

and heterogeneous mixtures. The homogeneous mixture will be the coating (dye) of an M&M. The

heterogeneous mixture is a mixture of sand (silicon dioxide, SiO2), salt (sodium chloride, NaCl), and iron

filings. Your goal is to separate the dyes of the M&M and to separate the solid mixture and determine its

mass percent composition.

This is Your Challenge:

1. Design an experiment that will determine if M&M candies contain mixtures of dyes or if they are single dyes. For example, is the orange color a result of one color or the mixing of two or more colors?

2. Design an experiment to separate the sand, salt and iron and determine the mass percent of each substance. You will turn in a lab report on your own paper.

Background:

Mass percent composition expresses the actual composition of a mixture in terms of the amount of each part. The

mass percentage of each component in a mixture is calculated as follows:

mass % of component = (mass of component total mass of mixture) x 100%

In order to determine the percent composition of a mixture, it is necessary to separate the components

quantitatively - without loss of material- and then measure the mass of each recovered component.

The sum of the mass percentage of all components in a mixture equals 100%.

A flow chart to illustrate the steps to separate a mixture would be very useful. The order of the steps is

extremely important.

Materials: You will have available to you chromatography paper, balance, glassware, hot plate, and magnet in

plastic bag.

Health Hazard: DO NOT EAT THE M & M’s

Pre-lab Questions:

1. The Department of Transportation uses a mixture of sand and salt to de-ice roadways in the winter.

The mixture contains 8.35 tons of salt and 6.28 tons of sand. What is the mass percent of each

component in the mixture?

2. A bakery needs a mixture of flour and sugar to make cookies. The mixture should contain 62.5% flour

and 37.5% sugar. You are in charge of ordering the components to make 275 pounds of the mixture.

How many pounds of flour and sugar should be ordered?

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Summary Notes on Mixtures

Mixtures are NOT pure substances. They are a physical combination of more than one

pure substance.

Mixtures can be any combination of solids, liquids and gases:

Solid-solid: Medicine tablet or metal alloys

Solid-gas: Pop Rocks candy

Solid-liquid: Ice water

Liquid-liquid: Lemon water

Gas-Liquid: Carbonated water

Gas-Gas: Air

Mixtures can be classifies as homogeneous or heterogeneous:

Homogeneous mixtures: Every sample you take will have the same distribution of components

throughout. Homogeneous mixtures look the same throughout. Solutions are homogeneous mixtures.

Salt water

Kool-Aid®

Air

Heterogeneous mixtures: Samples you take will have different distributions of components.

Different sizes or types of pieces can be seen (think “lumps,” “chunks,” etc.).

Raisin Bran cereal

Salt and pepper

Silver and gold beads

Vegetable soup

Mixtures can be separated by physical means:

Evaporation (heat the mixture to drive off the liquid; keep the solid)

Distillation (heat the mixture to drive off the liquid; cool the vapor to recover it)

Filtration (collect larger particles using filter paper)

Chromatography (used to separate inks and pigments)

Mechanical separation (using magnets or screens)

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Chem-is-try Name __________________________________Hour _____

Paradigm Lab (Matter): “Energy of the State” “If you can't take the heat, don't tickle the dragon.” -Anonymous

Introduction: Last year we talked about how water’s phase changes (and latent heat) affect our weather (remember, latent heat fueling hurricanes?). This year we’re going to dig deeper into how much energy is really involved (in other words, “what makes it possible to have multiple states of matter?”). You will revisit Q=mcΔT, and will explore the concepts of “heat of fusion” and “heat of vaporization.”

Here’s Your Challenge

Explain how/why the same compound (i.e. water) can exist as a solid, liquid, and gas by following water from

solid ice to the beginnings of steam.

Equipment You Can Use

beaker (250 ml) thermometer

glass stirring rod

ring stand and thermometer clamp

hot plate stop watch

ice cubes

Safety Precautions:

Wear your safety goggles at all times! Be careful when using hotplates or other heat

sources. Handle thermometers with care – never use a thermometer as a stirring rod.

Never heat an empty beaker! Wash hands with soap and water before leaving the lab.

Write Yourself a Procedure! Here are some hints…

1. There are three states of matter you can easily observe in a high school chemistry lab.

2. Changing between states of matter requires energy.

3. Not all changes in energy are associated with changes in temperature.

4. There is a data table provided on the next page. You will be expected to turn in a

graph and calculations according with the answers to the post-lab questions.

Post-Lab Questions

1. Does the temperature rise while the ice is melting? Using what you know about phase changes,

explain why you would or would not expect this result.

2. Does the temperature rise while the after the ice is melted? What does this tell you?

3. Does the temperature rise while the water is boiling? What does this tell you?

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Data Table: Temperature vs. Time Collect and Record Data for About 20 Minutes. Graph your data on the following page.

Time (sec) Temp (C) Time (sec) Temp (C) Time (sec) Temp (C)

30 440 860

60 470 890

90 500 920

120 530 950

150 560 980

180 590 1010

210 620 1040

240 650 1070

270 680 1100

300 710 1130

330 740 1160

360 770 1190

390 800 1220

420 830 1250

Apply What You’ve Learned!

Calculate the total amount of energy required to convert 100.00g of solid ice at –10C to steam at 110C.

The “c” or specific heat of solid ice is 2.06 J/gC and of liquid water is 4.18 J/gC.

The formula to determine the heat involved in a temperature change is Q = mcT.

For the phase change solid liquid, the “heat of fusion” is 334.16 J/g.

The formula we use is Q = Hfus mass.

For the phase change solid liquid, the “heat of vaporization” is 680.00 J/g.

The formula we use is Q = Hvap mass.

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Page 135

Summary Notes on Matter

Classification of Matter

States of Matter

Solid Liquid Gas

Lowest energy state

Molecules are

close-packed and have

very limited motion

Solids have a fixed

shape and fixed volume

Medium energy state

Molecules are farther

apart, move more freely

allowing liquids to flow

Liquids have a fixed

volume but take the

shape of their container

Highest energy state

Molecules close-packed

and have limited motion

Gases take the shape of

their container and

expand to fill the volume

of their container

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Energy and States of Matter

The Law of Conservation of Matter

Matter cannot be created or destroyed; it can only be rearranged. When elements react, total mass

of the products formed must equal the total mass of the reactants.

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Test Yourself on Mixtures and Matter

Matching Match the description in Column B with the correct term in Column A. Write the letter in the blank

provided. Each term matches with only one description, so choose the best description for each term.

Column A Column B

_____ 1. element

_____ 2. physical properties

_____ 3. compound

_____ 4. solid

_____ 5. physical change

_____ 6. solution

_____ 7. homogeneous

_____ 8. chemical properties

_____ 9. gas

_____ 10. chemical change

_____ 11. matter

_____ 12. liquid

_____ 13. heterogeneous

_____ 14. alloy

A. not the same throughout

B. has mass and occupies space

C. cannot be separated into simpler substances

D. the same throughout

E. atoms of different elements chemically combined

F. has a fixed shape and volume

G. a homogeneous mixture

H. composition of a substance is not affected

I. has a fixed volume but assumes the shape of its container.

J. mixture with metallic properties

K. ability to form new substances

L. no fixed volume or shape

M. a new substance is formed

N. inherent characteristics of a substance

Multiple Choice

Choose the one best answer and write its letter in the blank.

_____ 15. Anything that has mass and occupies space is called

a) solid b) liquid c) matter d) compound

_____ 16. Which of the following would be classified as a mixture?

a) carbon b) oxygen c) ice d) air

_____ 17. Which of the following is a chemical property?

a) melts at 0oC b) flammable c) conducts electricity d) floats in water

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_____ 18. Which of the following is a physical change?

a) rusting b) freezing c) rotting d) cooking

_____ 19. Which of the following is characteristic of a compound?

a) pure substance

b) homogeneous c) contains different kinds of atoms d) all of the above

_____ 20. A liquid is a state of matter that

a) flows. b) expands to fill its container completely. c) is easily compressed. d) has a definite shape.

_____ 21. Physical properties of a substance include

a) density and hardness. b) color and odor. c) melting point and boiling point. d) all of the above

_____ 22. Ice, liquid water, and water vapor (steam) have

a) similar physical and chemical properties. b) similar physical but different chemical properties. c) different physical but similar chemical properties. d) different physical and chemical properties.

________ 23. Which of the statements (a – c) is NOT true:

a) Compounds can be broken down into elements by chemical reactions. b) Compounds are a heterogeneous mixture of two or more elements. c) Compounds are pure substances. d) All of the above statements are true.

_____ 24. In a laboratory experiment, a sample of sugar is dissolved in water and the solution is then

evaporated to dryness. Upon further heating, the sugar turns brown. In correct sequence, the

following separate changes have occurred:

a) physical, chemical, physical b) physical, physical, chemical c) chemical, physical, chemical d) one chemical change and one physical change

Answers: Matching 1C, 2N, 3E, 4F, 5H, 6G, 7D, 8K, 9L, 10M, 11B, 12I, 13A, 14J Multiple Choice: 15 c, 16 d, 17 b, 18 b, 19 d, 20 a, 21 d, 22 c, 23 b, 24 b

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Vocabulary Challenge!

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Page 141

Lyrics to the Element Song http://www.privatehand.com/flash/elements.html

There's antimony, arsenic, aluminum, selenium, And hydrogen and oxygen and nitrogen and rhenium

And nickel, neodymium, neptunium, germanium, And iron, americium, ruthenium, uranium, Europium, zirconium, lutetium, vanadium

And lanthanum and osmium and astatine and radium And gold, protactinium and indium and gallium (inhale)

And iodine and thorium and thulium and thallium.

There's yttrium, ytterbium, actinium, rubidium And boron, gadolinium, niobium, iridium

And strontium and silicon and silver and samarium, And bismuth, bromine, lithium, beryllium and barium.

There's holmium and helium and hafnium and erbium And phosphorous and francium and fluorine and terbium And manganese and mercury, molybdenum, magnesium,

Dysprosium and scandium and cerium and cesium And lead, praseodymium, and platinum, plutonium, Paladium, promethium, potassium, polonium, and

Tantalum, technetium, titanium, tellurium, (inhale) And cadmium and calcium and chromium and curium.

``There's sulfur, californium and fermium, berkelium And also mendelevium, einsteinium, nobelium

And argon, krypton, neon, radon, xenon, zinc and rhodium And chlorine, carbon, cobalt, copper, tungsten, tin and sodium

These are the only ones of which the news has come to Ha'vard, And there may be many others but they haven't been dis’cavared.

Many thanks to Tom Lehrer for permission to publish these lyrics. © Tom Lehrer. All rights reserved

Page 142

Real World Reasons Your Love for Chemistry is Elemental!

Body Chemistry

What Different Elements Do For You

Page 143

Earth Chemistry

The Chemistry of Minerals and Alloys

Page 144

International Names for the Elements