Question

A mixture of N2 and O2 at 1 bar pressure contains N2 by 80% of weight. Calculate the partial pressure of N2 ?

Answer 1

Answer:

The partial pressure of N₂ is 0.82 bar

Explanation:

Pressure of the mixture P = 1 bar

Let the total mixture if 100 g

Then the N₂ will be 80 g and the O₂ willbe 20 g

Moles of N₂ $n_N$ = Weight of N₂/Molecular Weight

                                           = 80/14 = 40/7

Moles of O₂$n_O$  = Weight of O₂/Molecular Weight

                                           = 20/16 = 5/4

The partial pressure due to N₂ is given by

$P_{N}=(\frac{n_N}{n_N+n_O}) P$

$\implies P_{N}=(\frac{40/7}{40/7+5/4}) P$

$\implies P_{N}=(\frac{40/7}{(160+35)/28}) \times 1$

$\implies P_{N}=\frac{160}{195}$

$\implies P_{N}=0.82\text{ bar}$

Hope this is helpful.