Summer Work

Grade 7

American Program

Table of Contents

Part I – Matter ------------------------------------------------------------------------------------ Pages 1–6

Part II – Behavior of Gases -------------------------------------------------------------------- Pages 7–9

Part III – Acids and Bases ------------------------------------------------------------------- Pages 10–11

Part IV – Experiments ----------------------------------------------------------------------- Pages 12–14

Part I – Matter:

First Exercise: Read the following information on elements, compounds and mixtures. Fill in

the blanks where necessary.

A pure substance containing only one kind of ____________.

An element is always uniform all the way through (homogeneous).

An element _____________ be separated into simpler materials.

Over 100 existing elements are listed and classified on the ____________________.

A pure substance containing two or more kinds of _______________.

The atoms are _________________ combined in some way. Often times (but not

always) they come together to form groups of atoms called molecules.

A compound is always homogeneous (uniform).

Compounds ___________________ be separated by physical means. Separating a

compound requires a chemical reaction.

The properties of a compound are usually different than the properties of the elements it

contains.

Two or more ________________ or _________________ NOT chemically combined.

No reaction between substances.

Mixtures can be uniform (called ________________________) and are known as

solutions.

Mixtures can also be non-uniform (called ________________________).

Mixtures can be separated into their components by chemical or physical means.

The properties of a mixture are similar to the properties of its components.

The smallest identifiable unit of a compound is a(n) __________________, which is

made up of ____________________ which are chemically bonded.

Second Exercise: Classify each of the following as elements (E), compounds (C) or Mixtures

(M). Write the letter X if it is none of these.

___Diamond (C) ___Sugar (C6H12O6) ___Milk ___Iron (Fe)

___Air ___Sulfuric Acid (H2SO4) ___Gasoline ___Electricity

___Krypton (K) ___Bismuth (Bi) ___Uranium (U) ___Popcorn

___Water (H2O) ___Alcohol (CH3OH) ___Pail of Garbage ___A dog

___Ammonia (NH3) ___Salt (NaCl) ___Energy ___Gold (Au)

___Wood ___Bronze ___Ink ___Pizza

___Dry Ice (CO2) ___Baking Soda (NaHCO3) ___Titanium (Ti) ___Concrete

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Third Exercise: Match each diagram with its correct description. Diagrams will be used once.

A B C D E

___1. Pure Element – only one type of atom present.

___2. Mixture of two elements – two types of uncombined atoms present.

___3. Pure compound – only one type of compound present.

___4. Mixture of two compounds – two types of compounds present.

___5. Mixture of a compound and an element.

Fourth Exercise: Column A lists a substance. In Column B, list whether the substance is an

element (E), a compound (C), a Heterogeneous Mixture (HM), or a Solution (S). (Remember a

solution is a homogeneous mixture.) In Column C, list TWO physical properties of the

substance.

Column A Column B Column C

1. Summer Sausage

2. Steam

3. Salt Water

4. Pencil lead (Pb)

5. Dirt

6. Pepsi

7. Silver (Ag)

8. Toothpaste (Na2HPO4) 9. A burrito 10. Italian Dressing 11. Chicken Soup 12. Lemonade

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Fifth Exercise: Circle the correct choice in each of the following sentences.

1. A mixture ( is / is not ) a chemical combining of substances.

2. In a compound the ( atoms / molecules ) are ( chemically / physically ) combined so that

the elements that make up the compound ( keep / lose ) their identities and (do / do not)

take a new set of properties.

3. True or False: A mixture is always made up of a combination of elements.

4. In a mixture, the substances ( lose , keep ) their identities.

5. In a mixture, the substances involved ( can / cannot ) be separated by a simple physical

process.

6. In a compound the elements involved ( can / cannot ) be separated by a simple physical

process because the elements are ( physically combined / chemically bonded ).

7. True or False: An element can be broken down into simpler substances.

8. From the following list of substances, circle the ones that are elements:

silver carbon dioxide wood alcohol chromium

water hydrogen carbon nitrogen

oxygen gold sugar salt

air sulfur magnesium nickel

Sixth Exercise: Answer briefly the following questions.

1. Explain how to separate the sugar and water in a solution of sugar and water.

______________________________________________________________________________

______________________________________________________________________________

2. How would you separate a mixture of alcohol ad water?

______________________________________________________________________________

______________________________________________________________________________

3. How would you separate sand and water?

______________________________________________________________________________

______________________________________________________________________________

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Seventh Exercise: Classify the following as pure substances or as mixtures.

Air gasoline alcohol water sugar gold mercury oxygen salty water

pure substances mixtures

Eighth Exercise: Classify the following as heterogeneous or as homogeneous.

Sand and salt mixture hydrogen iron salty water unfiltered air iron with rust

Water an apple nitric acid tossed salad granite wood

heterogeneous homogeneous

Ninth Exercise: Classify the following as an element, a compound, a solution, or a

heterogeneous mixture.

Aluminum bread carbon dioxide sugar and water sulfuric acid an orange a pencil

Nitrogen gasoline water sulfur mercury water +coffee air alcohol iron+ sand

Element Compound heterogeneous Solution

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Tenth Exercise: Classify each of the following properties as Physical (P) or Chemical (C).

Eleventh Exercise: Classify each of the following changes as Physical (P) or Chemical (C).

Twelfth Exercise: Classify each of the following changes as Size-dependent (D) or Size-

independent (I).

Mass ______ Color ______

Density ______ Volume ______

Melting Point ______ Length ______

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Thirteenth Exercise: Place a check in the appropriate column.

Change Physical

Change

Chemical

Change

Salt dissolves in water

Hydrochloric acid reacts with magnesium to produce hydrogen gas

A piece of copper is cut in half

A sugar cube is grinded

Water is heated and changed to steam

Iron rusts

Alcohol evaporates

Ice melts

Milk sours (goes bad)

Sugar dissolves in water

Sodium and potassium react violently with water

Pancakes cook on a griddle

Grass grows on a lawn

Tire inflated with air

Food digested in stomach

Water is absorbed by a paper towel

Alcohol boils at 79oC

Paper burns

Water freezes at 0 oC

Fireworks explode

Compound gives off carbon dioxide when added to water

Clouds form in the sky

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Part II – Behavior of Gases:

First Exercise: Answer the following questions briefly.

1. What theory explains the behavior of gases with respect to conditions such as temperature and

pressure? ______________________

2. If you notice that a sealed bag of potato chips bulges when placed near a sunny window,

what can you hypothesize about the relationship between the temperature and pressure of an

enclosed gas?

______________________________________________________________________________

3. List three basic assumptions of the kinetic theory about the properties of gases.

* ____________________________________________________________________________

______________________________________________________________________________

* ____________________________________________________________________________

______________________________________________________________________________

* ____________________________________________________________________________

______________________________________________________________________________

4. List the name, the symbol, and a common unit for the three variables that are generally used

to describe the characteristics of a gas.

* ______________________________________________

* ______________________________________________

* ______________________________________________

5. How does pressure change inside a tire when you pump it up with a tire pump?

______________________________________________________________________________

6. What can happen if too much air is pumped into a tire?

______________________________________________________________________________

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7. What law states that for a given mass of gas at a constant temperature, the volume of the gas

varies inversely with pressure? ______________________

Second Exercise: The diagrams below show a sealed container at three pressures. Complete the

labels showing the gas pressure in each container.

200 Pa, 150 Pa, 100 Pa

Third Exercise: The diagrams below show a sealed container at two pressures. Complete the

labels showing the gas pressure and volume in each container.

Pressures: 100 Pa and 200 Pa

Volumes: 100 mL and 200 mL

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Pressure:

Volume:

Pressure:

Volume:

Fourth Exercise: This graph represents the relationship between pressure and volume for a

sample of gas in a container at a constant temperature.

1. Find P1 and V1:

____________________________________

2. Find P2 and V2:

____________________________________

3. Find P3 and V3:

____________________________________

4. Circle the letter of each sentence that is true about the relationship between the volume and the

pressure of an enclosed gas held at constant temperature.

a) When the pressure increases, the volume decreases.

b) When the pressure decreases, the volume increases.

c) When the pressure increases, the volume increases.

d) When the pressure decreases, the volume decreases.

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Part III – Acids and Bases:

Choose the correct answer.

1. What has a scale that measures from 0 to 14, with 0 being acidic and 14 basic?

a) pH

b) salinity

c) bio-indicators

d) dissolved oxygen

2. A reaction between an acid and a base is called ?

a) Buffer

b) Alkaline

c) Neutralization

d) Acid Rain

3. A strong base is characterized by which of the following?

a) A high concentration of H+ ions

b) a high concentration of OH- ions

c) a high pH

d) a low pH

e) both b and c

f) both a and d

4. The number that indicates a neutral pH.

a) 0

b) 5

c) 7

d) 10

5. Acids have a high pH.

a) True

b) False

6. Bases can often feel .

a) Fuzzy

b) Rough

c) Moldy

d) Slippery

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7. Which of the following are examples of acids?

a) vinegar

b) ammonia

c) vitamin c

d) alcohol

e) oranges

f) car batteries

g) baking soda

h) blood

8. Which of the following are examples of bases?

a) soap

b) vinegar

c) blood

d) alkaline batteries

e) baking soda

f) alcohol

g) ammonia

9. Which is the most acidic pH?

a) 2.5

b) 3.5

c) 4.5

d) 5.5

e) 6.5

10. Acids contain a "H group" and bases contain an "OH group".

a) True

b) False

11. A pH meter measures the of a substance.

a) basidity

b) level

c) acidity

d) color

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Part IV – Experiments:

First Experiment: EVAPORATION EXPERIMENT

You will need:

• glass or plastic (transparent) container

• water

• marker

• journal

• record sheet

Instructions:

1. Fill the container with water to about 3/4 full. Mark the level with a black permanent marker.

Measure the height of the water and record on record sheet.

2. In your journal write Day One. Draw a picture of what you see. Write a short description of

how you set up the experiment and what you think will happen (hypothesis).

3. Decide how often you are going to make an observation. The second time you make an

observation is Day Two, the third time Day Three, etc.

4. Each day, mark and date the new level. Draw a picture and write down your thoughts.

5. On the last day, record your final observations and measures. Draw a picture.

Do the following after your last observation:

1. Use the data on your record sheet make a graph.

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2. Research evaporation and write a short summary of what you have learned.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

3. Write a conclusion on the last page of your journal. What happened? What do you think

happened to the water?

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Second Experiment: As a MATTER of Fact…

Keep a running list of everything surrounding you that is matter. Categorize each item by listing

what state of matter each one is in.

Solids Liquids Gases

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Third Experiment: MELTING OF ICE CREAM

One point of experimentation is to find out for yourself the answer to a question. In this

experiment, you’ll be creating and answering your own question about how ice cream melts.

Question:

Will ice cream melt faster in a metal container or a plastic container?

Hypothesis: Write what you think will happen.

______________________________________________________________________________

______________________________________________________________________________

Materials: List the materials needed for your experiment.

_______________________ ________________________

_______________________ ________________________

Procedure: Describe clearly how you set up your experiment.

1. ____________________________________________________________________________

2. ____________________________________________________________________________

3. ____________________________________________________________________________

4. ____________________________________________________________________________

5. ____________________________________________________________________________

Conclusion: Write what actually happened & what the results might mean.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

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