Calculate the vapor pressure of water above the solution. The vapor pressure of pure water at this temperature is 0.0313 atm. Assume complete dissociation.

This question is incomplete, the complete question is;

The density of a 0.438 M solution of potassium chromate (K2CrO4) at 298 K is 1.063 g/mL.

Calculate the vapor pressure of water above the solution. The vapor pressure of pure water at this temperature is 0.0313 atm. Assume complete dissociation.

Pvap = atm

Pvap =  0.0306 atm

Explanation:

we know that; 1 L = 1000 mL of the solution

Mass of solution = volume x density

= 1000 x 1.063 = 1063 g

Moles of K2CrO4 = volume x concentration

= 1 x 0.438 = 0.438 mol

Mass of K2CrO4 = moles x molar mass = 0.438 x 194.19 = 85.055 g

Mass of water = 1063 - 85.055 = 977.945 g

Moles of water = mass / molar mass

977.945 / 18.02 = 54.27 mol

K2CrO4 => 2 K+ + Cr2O42-

Moles of ions = 3 x moles of K2CrO4

= 3 x 0.438 = 1.314 mol

Vapor pressure of solution = mole fraction of water x vapor pressure of water

= (54.27 / (54.27 + 1.314)) x 0.0313

= 0.0306 atm