2010 USNCO Local #16: Density of air
Source:
November 23, 2012
Problem Statement
Moist air is less dense than dry air at the same temperature and barometric pressure. Which is the best explanation for this observation? (A)\hspace{.05in}\ce{H2O} \text{ is a polar molecule but } \ce{N2} \text{ and } \ce{O2} \text{ are not} \qquad
(B)\hspace{.05in} \ce{H2O} \text{has a higher boiling point than } \ce{N2} \text{or} \ce{O2}\qquad
(C)\hspace{.05in}\ce{H2O} \text{has a lower molar mass than} \ce{N2} \text{or} \ce{O2}\qquad
(D)\hspace{.05in}\ce{H2O} \text{has a higher heat capacity than} \ce{N2} \text{or} \ce{O2}\qquad