Question

A vessel of volume $1000{\text{cm}}^3$ contains $0.2\text{mol}$ of oxygen and $0.3\text{mol}$ of carbon dioxide. If the temperature of the mixture is ${27}^{\circ }\text{C}$, find its pressure.

• A. $10\times {10}^5\text{Pa}$
• B. $12.5\times {10}^5\text{Pa}$
• C. $15\times {10}^5\text{Pa}$
• D. $17.5\times {10}^5\text{Pa}$

Answer 1

The correct option is B $12.5\times {10}^5\text{Pa}$

Ideal gas equation
$P=\frac{nRT}{V}$
Pressure due to oxygen $\left(P_{o_2}\right)=\frac{0.2\times 8.314\times (273+27)}{1000\times {10}^{-6}}$
$=4.98\times {10}^5\text{Pa}\approx 5\times {10}^5\text{Pa}$
Similarly
$P_{c{o}_2}=\frac{0.3\times 8.314\times 300}{1000\times {10}^{-6}}=7.482\times {10}^5$
$\approx 7.5\times {10}^5\text{Pa}$
So Total pressure in the vessel is
$P=P_{o_2}+P_{c{o}_2}$
$=5\times {10}^5+7.5\times {10}^5$
$=12.5\times {10}^5\text{Pa}$