Question

A vessel having volume of $8.21\text{L}$ is found to contain $3$ moles of $C{O}_2$ and $2$ moles of $He$. What is the partial pressure of $He$ in the vessel at $400\text{K}$?

• A. $2.4\text{atm}$
• B. $8\text{atm}$
• C. $12\text{atm}$
• D. $4.8\text{atm}$

Answer 1

The correct option is B $8\text{atm}$

The total pressure in the vessel $\left(P\right)=\frac{5\times RT}{V}=\frac{5\times 0.0821\times 400}{8.21}=20\text{atm}$
The partial pressure of $He={\chi }_{He}\times P=\frac{2}{5}\times 20=8\text{atm}$