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CHAPTER 12 Review

A. Completing Concepts

1. At one time, heat was thought to be a fluid called __________ which flowed in and out of objects.

2. Heat is the energy transferred from one object to another because of a difference in __________.

3. The __________ of a substance is a measure of the average kinetic energy of the molecules of the substance.

4. __________ and __________ are the two liquids most commonly used in thermometers.

5. At -273 C, the average kinetic energy of the molecules in matter is __________.

6. The first law of thermodynamics states that the total increase in the thermal energy of a system is the sum of the work done on it and the __________ added to it.

7. The second law of thermodynamics indicates that heat spontaneously flows from a(n) __________ substance to a(n) __________ substance, never the reverse.

8. __________ is the unavailability of energy.

9. __________ is the proper unit for all energy, including heat.

10. The __________ of a substance is the amount of heat needed to raise the temperature of a unit mass of the substance through 1 degree.

11. The energy of heat is __________ when changed to another form.

12. __________ is the heat needed to change a unit mass of a substance at its melting temperature from a solid into a liquid.

13. To change 1.0 g of water at 100C to steam at 100C, __________ J are required.

B. UNDERSTANDING CONCEPTS

1. The thermal energy content of a swimming pool at a temperature of 20C is __________ a cup of boiling water.

a. higher than

b. lower than

c. the same as

2. The Celsius degree is __________ the Kelvin.

a. larger than

b. smaller than

c. the same size as

3. At - 273C, the molecules of a substance

a. retain no energy.

b. retain some energy.

c. gain some energy.

d. lose energy.

4. Compared to most substances, water requires __________ heat to raise its temperature.

a. more

b. less

c. about the same

5. The energy required to change a substance from a liquid to a gas is usually __________ the energy required to change the substance from a solid to a liquid.

a. more than

b. less than

c. the same as

6. In order to express a Celsius temperature reading in Kelvin, you must add __________ to the Celsius temperature.

a. - 273

b. 32

c. 212

d. 273

7. Substance A has twice the specific heat of substance B. Equal amounts of A and B are mixed together. If substance A gains 14 J of heat, substance B loses __________ J of heat.

a. 7

b. 14

c. 21

d. 28


8. The heat required to change 3.0 g of ice at 0.0C to water at the same temperature is

a. 334 J.

b. 1002 J.

c. 2260 J.

d. 6780 J.

C. USING CONCEPTS

1. a. Express - 35C in K.

b. Express 85C in K.

c. Express 435 K in C.

d. Express 250 K in C.

2. Calculate the energy needed to raise the temperature of 185 g of copper from 151C to 201C. Copper has a specific heat of 385 J/kgC.

3. 75 g of water at 81C are mixed with 45 g of water at 21C. Calculate the equilibrium temperature of the mixture. Assume no heat is lost or gained by the surroundings.

4. A 50.0-g piece of aluminum is heated in boiling water, then transferred into 150.0g of water at 19.5C. After several minutes, the temperature of the water reaches equilibrium at 25C. Assuming no heat is lost or gained by the surroundings, what is the specific heat of aluminum expressed in J/kgC?

5. How many joules of thermal energy must be applied to a 2.00-kg block of ice, initially at 0.0C, to melt it and raise its temperature to 20.0C? {Hf = 3.34 x 105 J/kg; C = 4.18 x 103 J/kg K}

6. How many kilograms of water at 100.0C can be converted to steam by the addition of 1.13 x 107 joules of thermal energy? {Hv = 2.26 x 106 J/kg}

7. Calculate the energy needed to change 25 g of ice at 15.0C to steam at 130.0C. The specific heat of ice is 2.06 x 103 J/kgC and steam is 2.02 x 103 J/kgC.


If you have any questions, please email Ms. Cummings