Calculate the vapor pressure at 25°c of a solution containing 55.3 g ethylene glycol (hoch2ch2oh) and 285.2 g water. the vapor pressure of pure water at 25°c is 23.8 torr .

Vapor pressure of solution = 23.9 Torr

Explanation:

Let's apply the colligative poperty of vapor pressure to solve this:

ΔP = P° . Xm

ΔP = Vapor pressure of pure solvent - Vapor pressure of solution

We have solvent and solute mass, so let's find out the moles of each.

55.3 g / 62 g/mol = 0.89 moles

285.2 g / 18 g/mol = 15.84 moles

Let's determine the mole fraction of ethylene glycol.

Mole fraction = Moles of ethylene glyco / Total moles

0.89 moles / (0.89 + 15.84) = 0.053

25.3 Torr - Vapor pressure of solution = 25.3 Torr . 0.053

Vapor pressure of solution = 25.3 Torr . 0.053 - 25.3 Torr

Vapor pressure of solution = 23.9 Torr