What is the pressrure of each gas?

Question

A flask contains 2.5 moles CO2, 7.6 moles Ar, 1.2 moles Kr. The total pressure is 75.0 kPa

Answer 1

This problem is based on Dalton's law of partial pressures.

The total pressure exerted by a mixture of gases is the sum of the partial pressures of the components 

75.0 kPa = P_Co2+P_Ar+P_Kr

The partial pressure of each gas in a mixture is proportional to its mole fraction.

P/P_total = n/n_total

P= P_total x n/n_total

P_total = 75.0 kPa, n_total = 2.5+7.6+1.2= 11.3

P_co2= 75.0 x 2.5/11.3 = 16.6 kPa

P_Ar= 75.0 x 7.6/11.3 =   50.4 kPa

P_Kr = 75.0 x 1.2/11.3 = 7.96 kPa