Question

The density of a 0. 438 m solution of potassium chromate (k2cro4) at 298 k is 1. 063 g/ml.

Answer 1

Step-by-step explanation:

Consider 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