How do I calculate the vapor pressure of a solution?

Question

The vapor pressure of pure CH2Cl2 (with molecular weight 85 g/mol) is 133 torr at 0˚C and the vapor pressure of pure CH2Br2 (with molecular weight 174 g/mol) is 11 torr at the same temperature.
What is the total vapor pressure at 0˚C of a solution prepared from equal masses of these two substances?

Answer 1

Use Dalton's Law. The total pressure is the sum of the partial pressures.