CHEM 2061 SI
Chapter 11
Vaporization and Vapor Pressure
1. Arrange the following molecules in order of increasing vapor pressure:
H3COCH3
CH3CH2OH
H2O
2. Arrange the following molecules in order of increasing vapor pressure:
NF3
NH3
BCl3
3. Ammonia has a heat of vaporization of 23.4 kJ/mol and molar mass of 17.031 g/mol. What mass of ammonia
can be vaporized with 1760 kJ of heat?
4. A 1.20 L sample of methanol is vaporized at its boiling point. How much heat is required to complete the
process given a density of 0.792 g/cm3, heat of vaporization of 35.2 kJ/mol, and molar mass of 32.04 g/mol?
CHEM 2061 SI
Chapter 11
5. Ethanol has a heat of vaporization of 38.56 kJ/mol and a normal boiling point of 78.4°C. What is the vapor
pressure of ethanol at 15.0°C?
6. Benzene has a heat of vaporization of 30.72 kJ/mol and a normal boiling point of 80.1°C. At what temperature
does benzene boil if the external pressure is 445 torr?
7. A small amount of water (5.00 mL) condenses on a standard gold bar with a mass of 12.4 kg initially at 25.0°C.
Assuming that all of the heat from the condensation is absorbed by the metal, what is the final temperature of
the bar? Density of water = 1.00 g/mL, heat of vaporization of water at 25.0°C is 44.0 kJ/mol, molar mass of
water is 18.02 g/mol, and specific heat of gold at 25.0°C is 0.129 J/(g∙°C).