## Chemistry: The Molecular Science (5th Edition)

For a gas A, mole fraction $X_{A}=\frac{P_{A}}{P_{total}}$ Then, $X_{N_{2}}=\frac{P_{N_{2}}}{P_{total}}=\frac{575}{740.}=0.777$ $X_{O_{2}}=\frac{P_{O_{2}}}{P_{total}}=\frac{154}{740.}=0.208$ Similarly, $X_{Ar}=\frac{6.9}{740}=0.0093$ $X_{CO_{2}}=\frac{0.2}{740}=0.0003$ $X_{H_{2}O}=\frac{4.0}{740}=0.0054$