Q. 8.57 - An Introduction to General, Organic, and Biological Chemistry

Question

A gas mixture containing oxygen, nitrogen, and helium exerts a total pressure of $925 Torr$. If the partial pressures are oxygen $425 Torr$ and helium $75 Torr$, what is the partial pressure, $Torr$, of the nitrogen in the mixture?

Step-by-Step Solution

Answer

The partial pressure of nitrogen is $425 Torr$.

Step 1: Given Information

We need to find the partial pressure of nitrogen.

Step 2: Simplify

In a gas, mixture, each gas exerts its partial pressure, which is the pressure it would exert if it were the gas in the container. Dalton's law that the total pressure of a gas mixture is the sum of the partial pressures of the gases in the mixture. 

The total pressure is $P_{total}=925 Torr$

Oxygen $P_o=425 torr$

Helium $P_{he}=75 Torr$

Finding, the Nitrogen $P_n$ is:

$$\begin{gathered} P_{total}=P_o+P_{he}+P_N \\ {P}_N=P_{total}-P_o-P_{he} \\ {P}_N=925-425-75 \\ {P}_N=425 Torr \end{gathered}$$