intermolecular forces solutions worksheet.pdf

Name______________________________________________________Period________Date__________________________
Intermolecular Forces and Solutions
_____1. When an electrolyte is dissolved in water to form a solution, the vapor pressure of the solution (compared to pure
water):
a. Increases b. Decreases c. Remains the same d. May either increase or decrease
_____2. Which of the following is most soluble in water
a. SiO 2 b. CH 3 -O-CH 3 c. CaCO 3 d. NaCH 3 CO 2 e. C 6 H 6
_____3. Which of the following will have the lowest freezing point
a. 0.15 M glucose
b. 0.30 M sucrose
c. 0.15 M NaCl
d. 0.30 M CH 3 COOH
e. All the freezing points are equal
_____4. Which of the following will have the highest boiling point
a. 0.25 M NaCl
b. 0.50 M glucose
c. 0.25 M NaCH 3 CO 2
d. 0.50 M MgBr 2
e. All the boiling points are equal
_____5. Ethylene glycol (C 2 H 6 O 2 ) is added to water to make antifreeze. What volume of ethylene glycol must be added to
20.0 L of water to make a solution with a freezing point of -25.0ºC (Density of C 2 H 6 O 2 = 1.11 g/cm 3 . K F of water
= 1.86ºC kg/mol)
a. 15.0 L b. 20.0 L c. 1.50 L d. 12.0 L e. None of the above
_____6. 12.0 g of a non-volatile nonelectrolyte is dissolved in 125.0 g of water. The aqueous solution was found to have a
boiling point of 100.28ºC (at 1 atm). What is the molecular mass of the solute (K b for water equals 0.51ºC kg/mol)
a. 17.5 g/mol b. 5.27 g/mol c. 52.7 g/mol d. 175 g/mol e. None of the above
_____7. Arrange the following compounds in order of increasing melting point based on the relative strength of their
intermolecular forces:
Cl 2 , SiCl 4 , MgCl 2 , AlCl 3 , NaCl
a. NaCl < MgCl 2 < AlCl 3 < SiCl 4 < Cl 2
b. MgCl 2 < SiCl 4 < Cl 2 < NaCl < AlCl 3
c. Cl 2 < SiCl 4 < AlCl 3 < MgCl 2 < NaCl
d. Cl 2 < AlCl 3 < SiCl 4 < NaCl < MgCl 2
e. MgCl 2 < AlCl 3 < SiCl 4 < NaCl < Cl 2

______8. Arrange the following molecules in order of increasing boiling point:
a. I < II < III b. I < III < II c. II < I < III d. II < III < I e. III < I < II
_____9. Which of these solvents will dissolve the salt NaCl the most
a. Carbon tetrachloride
b. Acetone, (CH 3 ) 2 CO
c. Benzene, C 6 H 6
d. Methanol, CH 3 OH
e. All will dissolve NaCl
_____10. Which of the following substances is NOT likely to exhibit hydrogen bonding
a. CH 3 CH 2 OH
b. CH 3 NH 2
c. HOCH 2 CH 2 OH
d. (CH 3 ) 3 N
e. NH 2 OH
_____11. Helium atoms do not combine to form He 2 molecules, yet He atoms do attract one another through
a. Dipole-dipole forces.
b. Ion-dipole forces.
c. Dispersion forces.
d. Dipole-induced dipole forces.
e. Hydrogen bonding.
_____12. Which of the following characteristics indicate the presence of weak intermolecular forces in a liquid
a. A low heat of vaporization
b. A high critical temperature
c. A low vapor pressure
d. A high boil point
e. None of the above
_____13. Acetic acid has a heat of fusion of 10.8 kJ/mol and a heat of vaporization at 24.3 kJ/mol. What is the expected value
for the heat of sublimation of acetic acid
a. 35.1 kJ/mol
b. –13.5 kJ/mol
c. 15.5 kJ/mol
d. –35.1 kJ/mol
e. Not enough information is given to answer the question.
_____14. Given the following substances and their boiling points, which substance has the strongest intermolecular forces
Hydrogen chloride
Carbonyl fluoride
Carbon monoxide
Methane
-85ºC
-83ºC
-192ºC
-161ºC
a. Hydrogen chloride
b. Carbonyl fluoride
c. Carbon monoxide
d. Methane

Pressure
Liquid
1 atm
Solid
Vapor
0°C 100°C
Energy /
Temperature
_____15. In the mountains, the atmospheric pressure is about 0.8 atm. Which of the following statements is true
a. Water will boil at a temperature higher than 100°C
b. Water will boil at a temperature less than 100°C
c. Water will boil at a temperature of 100°C.
d. Water will not boil.
_____16. Under which of the following conditions will result in ice subliming into steam Assume that at the beginning the
ice is in -2°C at 1atm.
a. Exposing ice to pressure above 1atm at -2°C
b. Exposing ice to temperatures below 0°C at pressure above 5 atm
c. Exposing ice to -5°C at a pressure 0.001 atm
d. None of the above. Water can not under sublimation under any circumstances.
17. A solution is prepared by dissolving 2.75 g of an unknown nonvolatile, nonelectrolyte in water with a volume of 5.00 x 10 2
mL. The boiling point of the solution is 375 K. Calculate the molar mass of the unknown solute. (K b for water equals 0.51ºC
kg/mol) 5pts.