Answer to Question #96473 in General Chemistry for Angel

Question

A mixture consisting of 5.4 g CO and 9.2 g SO2, two atmospheric pollutants, has a pressure of 0.300 atm when placed in a sealed container. What is the partial pressure of the SO2?

Answer 1

According to Dalton's law, partial pressure of the SO₂ is equal to

$P_{SO_2}=x_{SO_2} \cdot P_{total}$

where x_SO2 is mole fraction of SO₂ and P_total is total pressure of gases.

As total pressure is known, we should find mole fraction of SO₂.

$x_{SO_2}=\frac{n(SO_2)}{n(SO_2)+n(CO)}=\frac{\frac{m(SO_2)}{M(SO_2)}}{\frac{m(SO_2)}{M(SO_2)}+\frac{m(CO)}{M(CO)}}=\frac{\frac{9.2g}{64 \frac{g}{mol}}}{\frac{9.2g}{64 \frac{g}{mol}}+\frac{5.4g}{28 \frac{g}{mol}}}=0.427$

Thus, partial pressure of the SO₂ is equal to

$P_{SO_2}=0.427 \cdot 0.300 atm = 0.128 atm$