Question

Gas mix has total pressure of 1234 Atm

50% N₂

35% O₂

15% He

What is the partial pressure of He?

Answer 1

Let total mass be 100 g

Molar mass of N2 = 28.02 g/mol

Molar mass of O2 = 32 g/mol

Molar mass of He = 4.003 g/mol

n(N2) = mass/molar mass

= 50.0/28.02

= 1.7844

n(O2) = mass/molar mass

= 35.0/32.0

= 1.0938

n(He) = mass/molar mass

= 15.0/4.003

= 3.7472

n(N2),n1 = 1.7844 mol

n(O2),n2 = 1.0938 mol

n(He),n3 = 3.7472 mol

Total number of mol = n1+n2+n3

= 1.7844 + 1.0938 + 3.7472

= 6.6254 mol

p(He),p = (n3*Ptotal)/total mol

= (3.7472 * 1234)/6.6254

= 697.9 atm

Answer: 697.9 atm