Answer
$0.2$
Work Step by Step
Given:
Number of moles of first gas $n_1 = 2\ moles$
Number of moles of second gas $n_2 =0.5\ moles $
From the ideal gas equation:
$PV = nRT$
We know that the formula for;
pressure for first gas $P_1 =\frac{n_1RT}{V}$
Pressure for second gas $P_2 = \frac{n_2RT}{V}$
Therefore, the Total pressure is:
$P= P_1+P_2$
$P= (n_1+n_2) \frac{RT}{V}$
This means that:
Fraction of total pressure to the pressure on second gas is:
$\frac{P_2}{P}=\frac{n_2\frac{RT}{V}}{(n_1+n_2)\frac{RT}{V}}$
$\frac{P_2}{P} = \frac{n_2}{n_1+n_2}$
$\frac{P_2}{P} = \frac{0.5}{2+0.5}$
$\frac{P_2}{P} = 0.2 $
