Question

a 10litre flask contain 0.2 moles of CH4, o.3 moles of H2,0.4 moles of N2 at 25 degree celcius. what is the partial pressure of each component and pressure inside flask?

Answer 1

Total no of mole present in flask =0.2 + 0.3 + 0.4 = 0.9 mole

use formula,
PV= nRT
P = nRT/V =0.9 × 0.082 × 298/10
P =2.199 atm

now use Dalton's law of Partial pressure .

first find mole fraction of all
mole fraction of CH4( Xa ) = 0.2/(0.2+0.3+0.5) =2/9

mole fraction of H2 ( Xb) = 0.3/0.9 = 1/3

mole fraction of N2( Xc) = 0.4/0.9 = 4/9

now,

Partial pressure of CH4 = Xa.P
= 2.199 × 2/9
= 0.4886 atm

partial pressure of H2 = Xb .P
=2.199 x 1/3 = 0.733 atm

partial pressure of N2 = Xc.P
=2.199 × 4/9 =0.977 atm