Exam 3

Question 1

Give the reason that antifreeze is added to a car radiator.

1.  The freezing point and the boiling point are elevated.
2.  The freezing point is elevated and the boiling point is lowered.
3.  The freezing point and the boiling point are lowered.
4.  The freezing point is lowered and the boiling point is elevated.
5.  None of the above.

Question 2

Calculate the freezing point of a solution of 40.0 g methyl salicylate, C 7H 6O 2, dissolved in 800. g of benzene, C 6H 6.    and the freezing point is 5.50°C for benzene.        

1. -2.09°C
2.  3.41°C
3.  7.59°C
4.  2.09°C
              

Question 3  

Identify the colligative property.          

1.  freezing point depression
2. vapor pressure lowering
3. osmotic pressure
4. boiling point elevation
5. all of the above

Question 4

  A solution is formed at room temperature by vigorously dissolving enough of the solid solute so that some solid remains at the bottom of the solution. Which statement below is TRUE?            

1. The solution is considered unsaturated.
2. The solution would be considered unsaturated if it were cooled a bit to increase the solubility of the solid.
3. The solution is considered supersaturated.
4. The solution is considered saturated.
5. None of the above are true.

Question 5

When dissolved in water, which compound is generally considered to be an Arrhenius acid?      

1. CH3CO2H
2. CH3CH2OH
3. Na2CO3
4. NaOH

Question 6

Determine ΔH vap for a compound that has a measured vapor pressure of 24.3 torr at 273 K and 135 torr at 325 K.            

1. 79 kJ/mol
2. 41 kJ/mol
3. 13 kJ/mol
4. 34 kJ/mol
5. 24 kJ/mol

Question 7

Which of the following statements is FALSE?            

1. Molecules with hydrogen bonding are more volatile than compounds with dipole-dipole forces.
2. The rate of vaporization increases with increasing surface area.
3. The rate of vaporization increases with decreasing strength of intermolecular forces.
4. The rate of vaporization increases with increasing temperature.
5. None of the above are false.

Question 8

Which of the following compounds exhibits hydrogen bonding?        

1.  CH3OCH3
2. HI
3. NH3
4. CH3Cl