Question

Tekanan uap air pada 29 derajat celcius diketahui sebesar 30 mmHg .pada suhu yg sama. hitunglah :
a. tekanan uap larutan urea 20 % (Mr urea = 60)
b. tekanan uap larutan urea 1 molal

Answer 1

A.
urea 20 % = 20 gram urea
Air 80% = 80 gram air
mol urea= gr/Mr = 20/60 = 1/3
mol air = gr/Mr = 80/18 = 40/9
mol larutan = 1/3 + 40/9 = 43/9

tekanan uap larutan



b.
urea 1 molal = 1 mol urea dalam 1 kg(1000 gram) air

mol urea = 1
mol air = gr/Mr =1000/18 = 55,56
mol larutan = 55,56 + 1 = 56,56

tekanan uap larutan