Question

The density of mixture of N₂ and O₂ is 1.3 g/L at NTP. Calculate the partial pressure of O₂ and N₂?

Answer 1

Suppose n₁ moles of O₂ and no moles of n₂ are mixed together. 

So, average molecular weight of gaseous mixture

\((M) = \frac{32\times n_1 + 28\times n_2}{n_1 +n_2 }\)

Similarly for mixture,

M = 29.137 g mol^-1 

From eq. (1) and (2),

Mole fraction of O₂ = 0.284 

Mole fraction of N₂ = 1 - 0.284 = 0.716

PO₂ = PT × nO₂ 

= 1 x 0.284 

= 0.284 atm 

PN₂ = PT × nN₂ 

= 1 × 0.716 

= 0.716 atm 

So, 

PO₂  = 0.284 atm 

PN₂ = 0.716 atm