# vapour pressure of water at293k is 17.53mm .calculate the vapour pressure of solution at 293k containing 6g of urea in 100g of water?

rohit kantheti
20 Points
12 years ago

use roults law.you know the pure vapour pressure of the solvent(17.53mm).,can find out mole fraction of the solute and hence can get the apour pressure of the solute

SAGAR SINGH - IIT DELHI
879 Points
12 years ago

Dear student,

• Raoult's Law states that for an ideal solution the partial vapor pressure of a component in solution is equal to the mole fraction of that component times its vapor pressure when pure: Pa = XaPao
Pa = vapor pressure of the solution
Pao = vapor pressure of pure solvent
Xa = mole fraction of the solvent
• The fractional vapor pressure lowering is equal to the mole fraction of the solute: Xb = (Pao - Pa) ÷ Pao
Pa = vapor pressure of the solution
Pao = vapor pressure of pure solvent
Xb = mole fraction of the solute
• Fractional vapor pressure lowering can be used to calculate molecular mass (formula weight) of a solute.

All the best.

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