EP 5 Review questions and answers

ep 5 review 2

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.

____ 1. What happens to the energy produced by burning gasoline in a car engine?
a. The energy is lost as heat in the exhaust.
b. The energy is transformed into work to move the car.
c. The energy heats the parts of the engine.
d. all of the above


____ 2. How does a calorie compare to a joule?
a. A calorie is smaller than a joule. c. A calorie is equal to a joule.
b. A calorie is larger than a joule. d. The relationship cannot be determined.


____ 3. Which of the following is NOT a form of energy?
a. light c. heat
b. pressure d. electricity


____ 4. If heat is released by a chemical system, an equal amount of heat will be ____.
a. absorbed by the surroundings c. released by the surroundings
b. absorbed by the universe d. released by the universe


____ 5. In an exothermic reaction, the energy stored in the chemical bonds of the reactants is ____.
a. equal to the energy stored in the bonds of the products
b. greater than the energy stored in the bonds of the products
c. less than the energy stored in the bonds of the products
d. less than the heat released


____ 6. A process that absorbs heat is a(n) ____.
a. endothermic process c. exothermic process
b. polythermic process d. ectothermic process


____ 7. The quantity of heat required to change the temperature of 1 g of a substance by 1 C is defined as ____.
a. a joule c. a calorie
b. specific heat d. density


____ 8. How many joules are in 148 calories? (1 cal = 4.18 J)
a. 6.61 J c. 148 J
b. 35.4 J d. 619 J


____ 9. What is the specific heat of a substance if 1560 cal are required to raise the temperature of a 312-g sample by 15 C?
a. 0.033 c. 0.99
b. 0.33 d. 1.33


____ 10. The heat capacity of an object depends in part on its ____.
a. mass c. shape
b. enthalpy d. potential energy


____ 11. When 45 g of an alloy, at 25 C, are dropped into 100.0 g of water, the alloy absorbs 956 J of heat. If the final temperature of the alloy is 37 C, what is its specific heat?
a. 0.423 c. 9.88
b. 1.77 d. 48.8


____ 12. How can you describe the specific heat of olive oil if it takes approximately 420 J of heat to raise the temperature of 7 g of olive oil by 30 C?
a. greater than the specific heat of water c. equal to the specific heat of water
b. less than the specific heat of water d. Not enough information is given.


____ 13. In an equilibrium reaction with a K of 1 10 , the ____.
a. reactants are favored c. the products are favored
b. reaction is spontaneous d. reaction is exothermic


Short Answer

14. What is the equilibrium constant for the following reaction?
3A + 2B 2C

15. Calculate the value of K for the following reaction at equilibrium.
2NClO(g) 2NO(g) + Cl (g)
An analysis of the equilibrium mixture in a 1-L flask gives the following results: NClO, 1.6 mol; NO, 6.4 mol; Cl , 0.49 mol

Essay

16. Explain the effects of reactant concentration and particle size on the rate of a reaction.

17. What is the effect of a catalyst on the rate of a reaction? Give an example of a catalyst.

ep 5 review 2
Answer Section

MULTIPLE CHOICE

1. ANS: D DIF: L1 REF: p. 505 OBJ: 17.1.1

2. ANS: B DIF: L1 REF: p. 506 OBJ: 17.1.1

3. ANS: B DIF: L1 REF: p. 505 OBJ: 17.1.1

4. ANS: A DIF: L1 REF: p. 506 OBJ: 17.1.1

5. ANS: B DIF: L2 REF: p. 506 OBJ: 17.1.1

6. ANS: A DIF: L1 REF: p. 506 OBJ: 17.1.2

7. ANS: B DIF: L1 REF: p. 507 OBJ: 17.1.2

8. ANS: D DIF: L1 REF: p. 507 OBJ: 17.1.3

9. ANS: B DIF: L1 REF: p. 509, p. 510
OBJ: 17.1.3

10. ANS: A DIF: L1 REF: p. 508 OBJ: 17.1.3

11. ANS: B DIF: L2 REF: p. 509 OBJ: 17.1.3

12. ANS: B DIF: L2 REF: p. 509, p. 510
OBJ: 17.1.3

13. ANS: C DIF: L1 REF: p. 556 OBJ: 18.2.3

SHORT ANSWER

14. ANS:
Keq =

DIF: L2 REF: p. 556 OBJ: 18.2.3

15. ANS:
K =
= 7.8

DIF: L3 REF: p. 556, p. 557 OBJ: 18.2.3

ESSAY

16. ANS:
A high concentration of reactants increases the reaction rate. This is because more molecules are present to collide each second. A small particle size increases the rate of a reaction. Because there is more surface area for a given mass of particles, more collisions are possible per second.

DIF: L3 REF: p. 545, p. 546 OBJ: 18.1.2

17. ANS:
A catalyst increases the rate of a reaction. A catalyst permits the formation of a less energetic activated complex. Platinum is a catalyst for certain reactions of gases.

DIF: L3 REF: p. 546, p. 547 OBJ: 18.1.2