Question

A gas mixture, with a total pressure of 300. torr, consists of equal masses of Ne (atomic weight 20.) and Ar (atomic weight 40.). What is the partial pressure of Ar, in torr

Answer 1

Answer:

The partial pressure will be "100 torr".

Explanation:

Given:

$P_{Ar} = 300 \ torr$

By assuming Ar and Ne having 50 gm each, we get

mol of Ne = $\frac{50}{20}$

                = $2.5 \ mol$

mol of Ar = $\frac{50}{40}$

               = $1.25 \ mol$

now,

$n_T= mol.A_r+mol.N_e$

     $=1.25+2.5$

     $=3.75$

then,

$X_{Ar}=\frac{n_{Ar}}{n_T}$

       $=\frac{1.25}{3.75}$

       $=0.33$

hence,

The partial pressure of Ar will be:

⇒ $P_{Ar} = P_T\times X_{AT}$

By substituting the values, we get

           $=300\times 0.33$

           $=100 \ torr$