# A gas mixture contains 0.70 moles of nitrogen gas, 0.20 moles of hydrogen gas, and 0.10 moles of methane (CH4). What is the partial pressure of nitrogen?

Sep 24, 2014

If the total pressure of the mixture is 1.00 atm, the partial pressure of nitrogen is 0.70 atm.

The partial pressure ${P}_{\text{i}}$ of a gas $i$ is equal to its mole fraction ${x}_{i}$ times the total pressure ${P}_{i}$ of the mixture.

${P}_{\text{i" =x_"i"P_"tot}}$ and ${x}_{i} = {n}_{\text{i"/n_"tot}}$.

${n}_{\text{tot" = n_"N₂" + n_"H₂" + n_"CH₄}}$ = (0.70 + 0.20 + 0.10) mol = 1.00 mol

${x}_{\text{N₂" = "0.70 mol"/"1.00 mol}}$ = 0.70

${P}_{\text{N₂" = x_"N₂"P_"tot}}$ = 0.70 × 1.00 atm = 0.70 atm