Two samples of water of equal volume are put into two dishes and kept at room temperature for several days. The water in the first dish is completely vaporized after 2.8 days while the water in the second dish takes 8.3 days to completely evaporate.What can you conclude about the two dishes?

Answer 1

When a non-volatile solute is placed in a volatile solvent, three things happen.
1. The boiling point is raised (which doesn't apply to this problem).
2. The freezing point is lowered (which doesn't apply to this problem).
3. The vapor pressure is lowered. (Wouldn't that apply to this problem? If the vapor pressure is lowered it will take longer for it to evaporate. right?)
To continue with what my freshman chemistry teacher said, (verbatim) "and the extent to which these things happen depends solely upon the number of dissolved particles.