Unit 7 Challenge Questions
1. How can you account for the fact that SO2 has a net dipole and dipole-dipole
intermolecular forces while CO2 has no net dipole and London dispersion
intermolecular forces? (Lewis structures needed to answer this question)
2. A 0.994 M solution of glucose, C6H12O6, in water has a density of 1.0624 g/ml at
20˚C. What is the concentration of this solution in:
a) Mass %?
b) Molality?
3. Assuming that seawater is a 3.5 mass % solution of NaCl and that its density is
1.00 g/ml, calculate both its boiling point and freezing point in ˚C. (For water, Kb
= 0.51 ˚C/m and Kf = 1.86 ˚C/m)
4. A compound that contains only C and H was burned in excess O2 to give CO2
and H2O. When 0.270 g of the compound was burned, the amount of CO2
formed reacted completely with 20.0 mL of 2.00 M NaOH solution according to
the equation
2 OH- (aq) + CO2 (g)  CO32- (aq) + H2O (l)
Unit 7 Challenge Questions
When 0.270 g of the compound was dissolved in 50.0 g of camphor, the resulting
solution had a freezing point of 177.9˚C. [Pure camphor freezes at 179.8˚C and has Kf =
37.7 ˚C/m]
a) What is the molar mass of the compound?
b) If the compound has the generic formula CnH2n +2 where “n” stands for any
integer, what is the molecular formula of the compound?