Question

a 5 L container has a mixture of 4 moles of carbon dioxide, three moles of oxygen and 5 moles of nitrogen. If the total pressure of the container is 123 kPa, what is the partial pressure of the oxygen in the container?

Answer 1

To solve this problem, we have to use Dalton's Law about partial pressure.

$P_{total}=P_{carbon}+P_{nitrogen}+P_{oxygen}$

However, we have to use the following formula to find each pressure.

$P_{\text{gas}}=x_1\cdot P_{Total}$

Where x refers to the fraction molar relation between the moles of the whole container and the moles of each gas.

Let's apply the formula to each gas

$\begin{gathered} P_{\text{carbon}}=\frac{4\text{mol}}{16\text{mol}}\cdot123kPa_{} \\ P_{\text{carbon}}=30.75kPa \\ P_{\text{nitrogen}}=\frac{5\text{mol}}{16\text{mol}}\cdot123\text{kPa} \\ P_{\text{nitrogen}}=38.44kPa \\ P_{\text{oxygen}}=\frac{3\text{mol}}{16\text{mol}}\cdot123\text{kPa}=23.06kPa \end{gathered}$

Therefore, the partial pressure of the oxygen is 23.06 kPa, approximately.