Cliffs AP Chemistry, 3rd Edition

Questions 12–16

Directions:Predict the change in entropy.

A. The change in entropy will be

positive.

B. The change in entropy will be zero.

C. The change in entropy will be

negative.

D. The change in entropy cannot be

determined from the information

given.

12. Cl 2 →2 Cl(g)

13. H 2 (g) at 5.0 atm →H 2 (g) at 1.0 atm

14. Sublimation of solid CO 2

15. 2 H 2 (g) + O 2 (g) →2 H 2 O(g)

16. PCl 5 (g) ↔PCl 3 (g) + Cl 2 (g)

17. Unknown element X combines with
    oxygen to form the compound XO 2. If
    44.0 grams of element X combine with
    8.00 grams of oxygen, what is the
    atomic mass of element X?

A. 16 amu

B. 44 amu

C. 88 amu

D. 176 amu

E. 352 amu

18. When water evaporates at constant

pressure, the sign of the change in

enthalpy

A. is negative

B. is positive

C. depends on the temperature

D. depends on the volume of the

container

E. does not exist; that is, the enthalpy

change is zero

19. Which of the following statements is

NOT correct?

A. At constant temperature, the

pressure of a certain amount of gas

increases with increasing volume.

B. At constant volume, the pressure of

a certain amount of gas increases

with increasing temperature.

C. At constant pressure, the volume of

a certain amount of gas increases

with increasing temperature.

D. In dealing with gas laws, the most

convenient scale of temperature to

use is the Kelvin temperature scale.

E. Equal numbers of molecules of all

gases exert about the same pressure

at a certain temperature and

volume.

Part IV: AP Chemistry Practice Test