Question

1. the law that states that the volume of a gas is directly proportional to its temperature in kelvins if the pressure and the number of particles is constant is

a. boyle’s law.
b. bose’s law.
c. einstein’s law.
d. charles’s law.

1. if the volume of a cylinder is reduced from 4.0 liters to 2.0 liters, the pressure of the gas in the cylinder will change from 100 kilopascals to

a. 50 kilopascals.
b. 150 kilopascals.
c. 200 kilopascals.
d. 400 kilopascals.

1. what type of change occurs when water changes from a solid to a liquid?

a. a phase change
b. a physical change
c. an irreversible change
d. both a and b

1. during a phase change, the temperature of a substance

a. increases.
b. decreases.
c. stays the same.
d. either increases or decreases, depending on the change.

1. during what phase change does the arrangement of water molecules become more orderly?

a. melting
b. freezing
c. boiling
d. condensing

1. the phase change in which a substance changes from a liquid to a gas is

a. deposition.
b. sublimation.
c. condensation.
d. vaporization.

1. the phase change in which a substance changes from a solid to a liquid is

a. freezing.
b. melting.
c. sublimation.
d. condensation.

1. which of the following phase changes is an endothermic change?

a. condensation
b. vaporization
c. deposition
d. freezing

Explanation:

1. Charles's law states that the volume of a gas is directly proportional to its temperature in kelvins when pressure and the number of particles are constant.
2. According to Boyle's law ($P_1V_1 = P_2V_2$), where $P_1 = 100$ kPa, $V_1=4.0$ L, $V_2 = 2.0$ L. So $P_2=\frac{P_1V_1}{V_2}=\frac{100\times4.0}{2.0}=200$ kPa.
3. When water changes from a solid to a liquid, it is both a phase change (a change between solid - liquid - gas states) and a physical change (no new substances are formed).
4. During a phase change, the temperature of a substance stays the same as the energy is used for the phase transition rather than changing the temperature.
5. During freezing, water molecules become more orderly as they form a crystalline structure.
6. The phase change from a liquid to a gas is vaporization.
7. The phase change from a solid to a liquid is melting.
8. Endothermic phase changes require heat input. Vaporization is endothermic as heat is needed to change a liquid to a gas.

Answer:

1. d. Charles's law.
2. c. 200 kilopascals.
3. d. both a and b
4. c. stays the same.
5. b. freezing
6. d. vaporization.
7. b. melting.
8. b. vaporization