Question

What are the partial pressure of each gas if A student performing an experiment has a bulb containing $14$ g of $N_2$, $64$ g of $O_2$, $8$ g of $He$, and $35$ g of ${Cl}_2$, at a total pressure of $380$ torr?

• A. 48 torr, 132 torr, 152 torr, 38 torr
• B. 78 torr, 152 torr, 182 torr, 98 torr
• C. 98 torr, 152 torr, 152 torr, 48 torr
• D. 38 torr, 152 torr, 152 torr, 38 torr

Answer 1

The correct option is D 38 torr, 152 torr, 152 torr, 38 torr

First to determine the number of moles of each gas.

14 g of $N_2=0.5$ mol
64 g of $O_2=2$ mol
8 g of $He=2$ mol
35 g of $C{l}_2=0.5$ mol
Partial pressure of $N_2=\frac{n_{N_2}}{n_{N_2}+n_{O_2}+n_{He}+n_{C{l}_2}}\times P_{total}=\frac{0.5}{0.5+2+2+0.5}\times 380=38$ torr

Partial pressure of $O_2=\frac{O_2}{n_{N_2}+n_{O_2}+n_{He}+n_{C{l}_2}}\times P_{total}=\frac{2}{0.5+2+2+0.5}\times 380=152$ torr

Partial pressure of $He=\frac{He}{n_{N_2}+n_{O_2}+n_{He}+n_{C{l}_2}}\times P_{total}=\frac{2}{0.5+2+2+0.5}\times 380=152$ torr

Partial pressure of $C{l}_2=\frac{C{l}_2}{n_{N_2}+n_{O_2}+n_{He}+n_{C{l}_2}}\times P_{total}=\frac{0.5}{0.5+2+2+0.5}\times 380=38$ torr

Hence, option $D$ is correct.