Phases Flashcards
Solid to liquid
melting/fusion
Liquid to solid
freezing
Liquid to gas
evaporation
Gas to liquid
condensation
Solid to gas
sublimation
Gas to solid
deposition
Melting: endothermic or exothermic?
endothermic
Freezing: endothermic or exothermic?
exothermic
Evaporation: endothermic or exothermic?
endothermic
Condensation: endothermic or exothermic?
exothermic
Sublimation: endothermic or exothermic?
endothermic
Deposition: endothermic or exothermic?
exothermic
What is the ∆H of sublimation equal to?
∆H(sublimation) = ∆H(melting) + ∆H(evaporation)
What is the ∆H of deposition equal to?
∆H(deposition) = ∆H(condensation) + ∆H(freezing)
Describe the pressure conditions required for evaporation.
The vapor pressure of the liquid must be greater than the partial pressure of the above gaseous phase.
Describe the pressure conditions required for condensation.
The vapor pressure of the liquid must be less than the partial pressure of the above gaseous phase.
Describe the pressure conditions required for boiling.
The vapor pressure of the liquid must be equal to the atmospheric pressure.
Describe the pressure conditions required for melting.
The vapor pressure of the liquid must be equal to the vapor pressure of the solid.
How might the partial pressure of the gas above a liquid be decreased?
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.
How might the partial pressure of the gas above a liquid be increased?
By increasing the concentration of that gas.
How might the vapor pressure of a liquid or solid be increased?
By increasing the temperature. Vapor pressure is dependent on temperature only, because it is influenced by kinetic energy.
What is Standard State?
1 atm, 293 K
What is STP?
1 atm, 273 K, molar volume = 22.4 L
What is the molar volume?
Occurs at STP at 22.4 L.
What is an adiabatic process?
A process with no heat transfer. q = 0, ∆E.
What is an isothermal process?
A process with no change in internal energy. ∆E = 0, 0 = q + w.
What is an isovolumetric process?
A process with no change in volume. w = 0, ∆E = q.
Is the volume of a real gas greater or less than that of an ideal gas?
Less. Molecular interactions are stronger because the volume is not infinite.
Is the pressure of a real gas greater or less than that of an ideal gas?
Greater.