Energy, Temperature and Phase Change
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
____ 1. A piece of metal is heated, then submerged in cool water. Which statement below describes what happens?
a. / The temperature of the metal will increase.b. / The temperature of the water will increase.
c. / The temperature of the water will decrease.
d. / The temperature of the water will increase and the temperature of the metal will decrease.
____ 2. When energy is changed from one form to another, ____.
a. / some of the energy is lost entirelyb. / all of the energy can be accounted for
c. / a physical change occurs
d. / all of the energy is changed to a useful form
____ 3. If heat is released by a chemical system, an equal amount of heat will be ____.
a. / absorbed by the surroundings / c. / released by the surroundingsb. / absorbed by the universe / d. / released by the universe
____ 4. Which of the following is transferred due to a temperature difference?
a. / chemical energy / c. / electrical energyb. / mechanical energy / d. / heat
____ 5. The quantity of heat required to change the temperature of 1 g of a substance by 1C is defined as ____.
a. / a joule / c. / a calorieb. / heat capacity / d. / density
____ 6. What is the amount of heat required to raise the temperature of 200.0 g of aluminum by 10C? (specific heat of aluminum = 0.88 )
a. / 1800 J / c. / 18,000 Jb. / 180,00 J / d. / 1,800,000 J
____ 7. What is the specific heat of a substance if 6520 J are required to raise the temperature of a 312-g sample by 15C?
a. / 0.35 / c. / 1.4b. / 5.2 / d. / 22
____ 8. How many kilocalories of heat are required to raise the temperature of 225 g of aluminum from 20C to 100C? (specific heat of aluminum = 0.21 )
a. / 0.59 kcal / c. / 85 kcalb. / 3.8 kcal / d. / none of the above
____ 9. When 45 g of an alloy, at 25C, are dropped into 100.0 g of water, the alloy absorbs 956 J of heat. If the final temperature of the alloy is 37C, what is its specific heat?
a. / 0.57 / c. / 0.80b. / 0.85 / d. / 1.8
____ 10. The specific heat of silver is 0.24 . How many joules of energy are needed to warm 4.37 g of silver from 25.0C to 27.5C?
a. / 2.62 J / c. / 45.5 Jb. / 0.14 J / d. / 0.022 J
____ 11. During a phase change, the temperature of a substance ____.
a. / increases / c. / remains constantb. / decreases / d. / may increase or decrease
____ 12. To calculate the amount of heat absorbed as a substance melts, which of the following information is needed?
a. / the mass of the substance / c. / the change in temperatureb. / the specific heat of the substance / d. / the density of the sample
____ 13. When 10 g of diethyl ether is converted to vapor at its boiling point, about how much heat is absorbed? (CHO, H = 212 J/g, boiling point: 34.6C)
a. / 2 kJ / c. / 0.2 kJb. / 2 J / d. / Not enough information is given.
____ 14. 500.0 g of ice at 0˚C melts and becomes water at 0˚C. How much energy is released into the surroundings?
a. / 1700 J / c. / 167 kJb. / 2100 J / d. / 1100 kJ
____ 15. 49 g of ice at -10.0˚C is heated on a burner until it becomes 49 g of water at 0.0˚C. How much energy was supplied by the burner?
a. / 1.0 kJ / c. / 17 kJb. / 16 kJ / d. / 110 kJ
____ 16. 5.0 g of steam at 100˚C lands on a glass of iced tea and cools down to 15˚C. How much energy did the glass of iced tea absorb from the steam as it cooled?
a. / 1.7 kJ / c. / 11 kJb. / 1.8 kJ / d. / 13 kJ
____ 17. 100.0 g of ice at -20˚C is put into a pressure cooker and heated with 50 kJ of energy. What is the final temperature of the water once the ice is melted?
a. / 20˚C / c. / 60˚Cb. / 30˚C / d. / 100˚C
Energy, Temperature and Phase Change
Answer Section
MULTIPLE CHOICE
1. ANS: D
What is your system? What is the surroundings? Energy that leaves one must enter the other. Energy must be conserved.
DIF: L1 REF: p. 506 OBJ: 17.1.1
2. ANS: B
What is the Law of Conservation of Energy?
DIF: L1 REF: p. 506 OBJ: 17.1.1 STO: 3.1.10.E.1
3. ANS: A
What is the Law of Conservation of Energy?
DIF: L1 REF: p. 506 OBJ: 17.1.1 STO: 3.4.12.B.1
4. ANS: D
In our particle model, a difference in temperature is related to a difference in the speed of the particles. If a group of slow (cold) particles begins to collide with a group of faster (warmer) particles what will be the overall effect on the speed of each group of particles?
DIF: L1 REF: p. 506 OBJ: 17.1.1
5. ANS: B DIF: L1 REF: p. 507 OBJ: 17.1.2
STO: 3.4.12.B.4
6. ANS: A
, The energy provided by heating is causing an increase in Thermal Energy
DIF: L1 REF: p. 508 OBJ: 17.1.3 STO: 3.4.12.B.4
7. ANS: C
, The energy provided by heating is causing an increase in Thermal Energy
DIF: L1 REF: p. 509, p. 510 OBJ: 17.1.3
STO: 3.4.12.B.4
8. ANS: B DIF: L1 REF: p. 508 OBJ: 17.1.3
STO: 3.4.12.B.4
9. ANS: D
, The energy provided by heating is causing an increase in Thermal Energy. What is being heated, the alloy or the water? Careful what mass you use!
DIF: L2 REF: p. 509 OBJ: 17.1.3 STO: 3.4.12.B.4
10. ANS: A
, The energy provided by heating is causing an increase in Thermal Energy
DIF: L2 REF: p. 509, p. 510 OBJ: 17.1.3
STO: 3.4.12.B.4
11. ANS: C
During a phase change, which of the energy accounts is changing - Interaction energy or Thermal Energy? Which account remains constant?
DIF: L1 REF: p. 520 OBJ: 17.3.1 STO: 3.4.10.A.4
12. ANS: A
If it is melting, what is the temperature change? When it is melting, which constant do you use in the equation?
DIF: L2 REF: p. 521 OBJ: 17.3.1 STO: 3.4.12.B.4
13. ANS: A
, The energy provided by heating is causing an increase in Interaction Energy.
DIF: L2 REF: p. 524 OBJ: 17.3.2
14. ANS: C
, The energy released to the surroundings is causing a decrease in Interaction Energy. Which constant should you choose if water is melting?
15. ANS: C
What happens to the ice at 0˚C? This problem includes changes in Interaction energy AND thermal energy. You must solve for each one separately and combine your answers.
16. ANS: D
The steam undergoes a phase change AND cooling. Be sure to take the energy changes in both processes into account when you do the math.
17. ANS: B
As the ice is being heated it undergoes three separate changes. First you have to heat the ice to its melting point. Then you have to melt the ice into water. Finally, the water must be heated to a new temperature. Be sure to solve the first two parts given the appropriate temperatures and constants. Then when you know how much of the original 50 kJ of energy remain, you can use that to solve for the final temp of the water.