Phases

Question 1

Solid to liquid

Answer 1

melting/fusion

Question 2

Liquid to solid

Answer 2

freezing

Question 3

Liquid to gas

Answer 3

evaporation

Question 4

Gas to liquid

Answer 4

condensation

Question 5

Solid to gas

Answer 5

sublimation

Question 6

Gas to solid

Answer 6

deposition

Question 7

Melting: endothermic or exothermic?

Answer 7

endothermic

Question 8

Freezing: endothermic or exothermic?

Answer 8

exothermic

Question 9

Evaporation: endothermic or exothermic?

Answer 9

endothermic

Question 10

Condensation: endothermic or exothermic?

Answer 10

exothermic

Question 11

Sublimation: endothermic or exothermic?

Answer 11

endothermic

Question 12

Deposition: endothermic or exothermic?

Answer 12

exothermic

Question 13

What is the ∆H of sublimation equal to?

Answer 13

∆H(sublimation) = ∆H(melting) + ∆H(evaporation)

Question 14

What is the ∆H of deposition equal to?

Answer 14

∆H(deposition) = ∆H(condensation) + ∆H(freezing)

Question 15

Describe the pressure conditions required for evaporation.

Answer 15

The vapor pressure of the liquid must be greater than the partial pressure of the above gaseous phase.

Question 16

Describe the pressure conditions required for condensation.

Answer 16

The vapor pressure of the liquid must be less than the partial pressure of the above gaseous phase.

Question 17

Describe the pressure conditions required for boiling.

Answer 17

The vapor pressure of the liquid must be equal to the atmospheric pressure.

Question 18

Describe the pressure conditions required for melting.

Answer 18

The vapor pressure of the liquid must be equal to the vapor pressure of the solid.

Question 19

How might the partial pressure of the gas above a liquid be decreased?

Answer 19

By the wind, or anything else that increases the velocity of the gas. Increasing the velocity decreases the partial pressure of a gas, because gaseous partial pressure is dependent on velocity.

Question 20

How might the partial pressure of the gas above a liquid be increased?

Answer 20

By increasing the concentration of that gas.

Question 21

How might the vapor pressure of a liquid or solid be increased?

Answer 21

By increasing the temperature. Vapor pressure is dependent on temperature only, because it is influenced by kinetic energy.

Question 22

What is Standard State?

Answer 22

1 atm, 293 K

Question 23

What is STP?

Answer 23

1 atm, 273 K, molar volume = 22.4 L

Question 24

What is the molar volume?

Answer 24

Occurs at STP at 22.4 L.

Question 25

What is an adiabatic process?

Answer 25

A process with no heat transfer. q = 0, ∆E.

Question 26

What is an isothermal process?

Answer 26

A process with no change in internal energy. ∆E = 0, 0 = q + w.

Question 27

What is an isovolumetric process?

Answer 27

A process with no change in volume. w = 0, ∆E = q.

Question 28

Is the volume of a real gas greater or less than that of an ideal gas?

Answer 28

Less. Molecular interactions are stronger because the volume is not infinite.

Question 29

Is the pressure of a real gas greater or less than that of an ideal gas?

Answer 29

Greater.