Vapor Pressure of a Solution of a Non-Volatile Solute

Vapor Pressure of a Solution of a Non-Volatile Solute.?

A solution is made by dissolving 32.5g of urea (H2NCONH2, a non-volatile non-electrolyte) in 284g of water.
Calculate the vapour pressure of this solution at 50°C. (note the vapour pressure of pure water at 50°C is 92.5 torr.)


Chemistry
Best Answer - Chosen by Asker

Number of moles of urea = 32.5 / 60 = 0.542 mol
Number of moles of water = 284/18 = 15.778 mol

Mole fraction of water = 15.778 / ( 15.778 + 0.542) = 0.967

Using Raoult's Law,
Vapour pressure = 0.967 x 92.5 = 89.45 torr.