30 gram urea (mr=60) dilarutkan dalam 90 gram air (mr=18) pada suhu 25°c tekanan uap jenuh pelarut air =24mmHg tentukan: tekanan uap larutan dan penurunan tekan

30 gr urea (Mr = 60)
90 gr air (Mr = 18)
Po = 24 mmHg

ditanya : P & ∆P ... ?

n urea = gr/Mr = 30/60 = 0,5
n air = gr/Mr = 90/18 = 5

X pelarut = n air / (n air + n urea)
X pelarut = 5 / (5 + 0,5)
X pelarut = 5 / 5,5
X pelarut = 0,909

*P = Po . X pelarut
P = 24 . 0,909
P = 21,81 mmHg

*∆P = Po - P
∆P = 24 - 21,81
∆P = 2,19 mmHg