Choose the correct answer for each question.

1. A liquid boils when it

   1.   ?    vapor pressure is exactly 1 atmosphere
   2.   ?    vapor pressure is equal to, or greater than, the external pressure pushing on it.
   3.   ?    temperature is equal to 273K (standard temperature)
   4.   ?    temperature is greater than room temperature

2. Acetic acid has a heat of fusion of 10.8kJ/mol and a heat of vaporization of 24.3kJ/mol. What is the expected value for the heat of sublimation of acetic acid?

   1.   ?    35.1kJ/mol
   2.   ?    -13.5kJ/mol
   3.   ?    +13.5kJ/mol
   4.   ?    -35.1kJ/mol
   5.   ?    cannot tell from the data.

3. The vapor pressure of ethanol is 400 mmHg at 63.5^oC. Its molar heat of vaporization is 39.3kJ/mol. What is the vapor pressure of ethanol in mmHg at 34.9^oC?

   1.   ?    1510
   2.   ?    100
   3.   ?    200
   4.   ?    0.0099
   5.   ?    4.61

4. The vapor pressure of a liquid in a closed container depends upon

   1.   ?    the amount of liquid.
   2.   ?    the surface area of the liquid.
   3.   ?    the volume of the container
   4.   ?    the temperature.
   5.   ?    none of the above.

5. 3.59 g of water is placed into an evaculated 1.50L flask at 30^oC. What mass of water will evaporate? (vapor pressure of water at this temperature is 31.82 mmHg.

   1.   ?    0.0454g
   2.   ?    0.454g
   3.   ?    0.04187g
   4.   ?    2.52x10^-3g
   5.   ?    0.4187

6. Palladium crystallizes in a face-centered ubic unit cell. Its density if 12.0g/cm³ at 27^oC. Calculate the atomic radius of Pd.

   1.   ?    140pm
   2.   ?    1.95x10^-8nm
   3.   ?    1.95x10^-8cm
   4.   ?    154pm
   5.   ?    0.109nm

7. The number of atoms in a face-centered cubic unit cell is

   1.   ?    1
   2.   ?    2
   3.   ?    3
   4.   ?    4
   5.   ?    8

8. Which property of water allows a paper clip to float on it without sinking?

   1.   ?    Viscosity
   2.   ?    Surface tension
   3.   ?    Density
   4.   ?    Specific heat
   5.   ?    Adhesive Force

9. Which of the following indicates the presence of strong intermolecular forces in a liquid?

   1.   ?    A low heat of vaporization.
   2.   ?    A low critical temperature.
   3.   ?    A low vapor pressure.
   4.   ?    A low boiling point.
   5.   ?    None of the above.

10. Which one of the following substances will have both London forces and dipole-dipole forces?

    1.   ?    HCl
    2.   ?    BCl₃
    3.   ?    Br₂
    4.   ?    H₂
    5.   ?    CO₂