Science Notebook • Energy and Chemical Change253

Program: TX HS Science Component: CMC SCI NTBKPDF PASS

Vendor: LASERWORDS Grade: N/A

15 Energy and Chemical ChangeBIGIDEAWrite the Big Idea for this chapter.

Use the “What I Know” column to list the things you know about the Big Idea. Then list the questions you have about the Big Idea in the “What I Want to Find Out” column. As you read the chapter, fill in the “What I Learned” column.

KWhat I Know

WWhat I Want to Find Out

LWhat I Learned

Chemical reactions usually absorb or release energy.

Copy

righ

t © M

cGra

w-H

ill E

duca

tion

253_274_CMC_SN_C15_665563.indd 253253_274_CMC_SN_C15_665563.indd 253 5/6/13 8:33 AM5/6/13 8:33 AM

Science Notebook • Energy and Chemical Change254

Program: TX HS Science Component: CMC SCI NTBKPDF PASS

Vendor: LASERWORDS Grade: N/A

MAIN IDEAWrite the Main Idea for this lesson.

Recall the definition of the Review Vocabulary term.

temperature

Define each New Vocabulary term.

energy

law of conservation of energy

Chemical potential energy

heat

calorie

j oule

specific heat

15 Energy and Chemical Change1 Energy

REVIEW VOCABULARY

temperature

NEW VOCABULARY

energy

law of conservation of

energy

Chemical potential energy

heat

calorie

joule

specific heat

2(G), 11(A), 11(B), 11(D)

Energy can change form and flow, but it is always conserved.

law stating that in any chemical

reaction or physical process, energy can be converted from one form to

another, but it is neither created nor destroyed

the energy stored in a substance because

of its composition

energy that is in the process of flowing from a warmer object to a

cooler object

the amount of heat required to raise the temperature of one

gram of pure water one degree Celsius (1ºC)

SI unit for heat and energy; one joule is equivalent to 0.2390 calories

the amount of heat required to raise the temperature of

one gram of a substance by one degree Celsius

the ability to do work or produce heat

a measure of the average kinetic energy of the particles in

a sample of matter

Copyright © M

cGraw

-Hill Education

253_274_CMC_SN_C15_665563.indd 254253_274_CMC_SN_C15_665563.indd 254 5/6/13 8:33 AM5/6/13 8:33 AM

Science Notebook • Energy and Chemical Change255

Program: TX HS Science Component: CMC SCI NTBKPDF PASS

Vendor: LASERWORDS Grade: N/A

1 Energy (continued)

Use with pages 516–518. Compare and contrast kinetic energy with potential energy.

On the curve below that represents the skier on a ski slope on page 516, label the place of greatest kinetic energy A, least kinetic energy B, greatest potential energy C, and least potential energy D.

Describe the skier above as a function of the law of conservation of energy.

Explain chemical potential energy.

Chemical energy of a substance is a result of the

arrangement of its and the strength of the

joining the atoms. During some reactions, such as burning , much of the potential energy may be released as . Some of the energy may be converted to work, which is a

form of energy.

GET IT? State the law of conservation of energy in your own words.

Kinetic energy is the energy of motion. Potential energy is energy of the

composition or position of an object.

Before the skier starts, there is potential energy that is converted to

kinetic energy, then to potential energy as the skier stops. Energy

changes form.

Energy may change forms but is never gained or lost.

potential

chemical bondsatoms

chemical

fuel

heat

kinetic

BC

DA

Copy

righ

t © M

cGra

w-H

ill E

duca

tion

253_274_CMC_SN_C15_665563.indd 255253_274_CMC_SN_C15_665563.indd 255 5/6/13 8:33 AM5/6/13 8:33 AM

Science Notebook • Energy and Chemical Change256

Program: TX HS Science Component: CMC SCI NTBKPDF PASS

Vendor: LASERWORDS Grade: N/A

1 Energy (continued)

Identify each symbol in the equation for specific heat.q = c × m × ΔT

 represents heat absorbed or released

 represents the specific heat of the substance

 represents mass of a sample in grams

represents a change in temperature

Summarize. Fill in the blanks to help you take notes while you read Example Problem. Problem

The temperature of a sample of iron with a mass of 10.0 g changed from 50.4°C to 25.0°C with the release of 114 J heat. Determine the specific heat of iron.1. Analyze the Problem

Known: Unknown:

energy released = specific heat of iron = ?

ΔT =

mass of iron =

2. Solve for the UnknownWrite the equation for heat absorption.

q =

Solve for c.

q = c =

c =

3. Evaluate the AnswerIf the values used in the calculations have significant figures, the answer must also have significant figures. The calculated value matches the value for iron in Table 2.

Use with pages 519–521.

q

c

m

ΔT

114 J

50.4°C – 25.0°C = 25.4°C

10.0 g

threethree

c × m × ΔT

c × m × ΔTm × ΔT m × ΔT

q

114 J(10.0g) (25.4°C)

=0.499 J / (g.°C)

Copyright © M

cGraw

-Hill Education

253_274_CMC_SN_C15_665563.indd 256253_274_CMC_SN_C15_665563.indd 256 5/6/13 8:33 AM5/6/13 8:33 AM

Science Notebook • Energy and Chemical Change257

Program: TX HS Science Component: CMC SCI NTBKPDF PASS

Vendor: LASERWORDS Grade: N/A

REVIEW IT !

7. MAINIDEA Explain how energy changes from one form to another in an exothermic reaction. In an endothermic re action.

8. Distinguish between kinetic and potential energy in the following examples: two separated magnets; an avalanche of snow; books on library shelves; a mountain stream; a stock-car race; separation of charge in a battery.

9. Explain how the light and heat of a burning candle are related to chemical potential energy.

10. Calculate the amount of heat absorbed when 5.50 g of aluminum is heated from 25.0°C to 95.0°C. The specific heat of aluminum is 0.897 J/(g∙°C).

11. Interpret Data Equal masses of aluminum, gold, iron, and silver were left to sit in the Sun at the same time and for the same length of time. Use Table 2 to arrange the four metals according to the increase in their temperatures from largest increase to smallest.

1 Energy (continued)

Chemical potential energy changes to heat in exothermic reactions, and the heat is released. In

endothermic reactions, heat is absorbed and changed to chemical potential energy.

Two separated magnets illustrate potential energy. In a snow avalanche, positional potential energy

changes to kinetic energy. Books on a shelf illustrate positional potential energy. As water races down

a mountain stream, positional potential energy changes to kinetic energy. In a stock car race,

chemical potential energy changes to kinetic energy. The separation of charge in a battery illustrates

electrical potential energy.

Chemical poten tial energy, contained in the candle, is changed to energy in the form of light and heat

and released as the chemical combustion reaction takes place.

345 J

The temperature change is inversely proportional to specific heat: aluminum, iron, silver, gold.

Copy

righ

t © M

cGra

w-H

ill E

duca

tion

253_274_CMC_SN_C15_665563.indd 257253_274_CMC_SN_C15_665563.indd 257 5/6/13 8:33 AM5/6/13 8:33 AM