Question

Calculate the total pressure in a 10 litre cylinder which contains 0.4 g he, 1.6 g oxygen and 1.4 g nitrogen at 27°c. Also calculate the partial pressure of he gas in the cylinder. Assume ideal behavious for gases

Answer 1

PV = nRT V = 10 litre T = 27ºC = 300K
nHe = 0.4/4 = 0.1
 N2 = 1.4/ 28= 0.05, 

O2 = 1.6/32= 0.05

Total no. of moles = 0.1 + 0.05 + 0.05  0.2
PV = nRT  P× 10 = 0.2 × 0.082 × 300 = 0.04926  P = 0.492 atm
Partial pressure = Total pressure × molefraction
PHe = 0.492 × 0.1/ 0.2
 = 0.246 atm

PN2 = 0.492 × 0.05/ 0.2
 = 0.123 atm

PO2 = 0.492 × 0.05/0.2
 = 0.123 atm.

Mark Brian last

Answer 2

Answer:

Moles of He = w/M = 0.4/4 = 0.10

Moles of O = w/M = 1.6/32 = 0.05 2

Moles of N = w/M = 1.4/28 = 0.05 2

Total moles = 0.2

PV = nRT

P x 10 =  0.2 x 0.082 x 300

P = 0.492 atm