The total pressure exerted by a mixture of 1.50 g of H₂and 5.00 g of N₂in a 5.00- L vessel at 298 K is atm. A) 4.54 B) 32.4 C) 1.06 D) 5.27 E) 9.08

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Quizplus · Accepted Answer

The correct answer is A because the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each gas. The partial pressure of a gas is equal to the mole fraction of that gas multiplied by the total pressure. The mole fraction of a gas is equal to the number of moles of that gas divided by the total number of moles of all gases in the mixture. The number of moles of a gas is equal to its mass divided by its molar mass. The molar mass of H₂ is 2.016 g/mol and the molar mass of N₂ is 28.01 g/mol. Therefore, the number of moles of H₂ is 1.50 g / 2.016 g/mol = 0.744 mol and the number of moles of N₂ is 5.00 g / 28.01 g/mol = 0.178 mol. The total number of moles of gases in the mixture is 0.744 mol + 0.178 mol = 0.922 mol. The mole fraction of H₂ is 0.744 mol / 0.922 mol = 0.807 and the mole fraction of N₂ is 0.178 mol / 0.922 mol = 0.193. The partial pressure of H₂ is 0.807 * 1 atm = 0.807 atm and the partial pressure of N₂ is 0.193 * 1 atm = 0.193 atm. The total pressure exerted by the mixture of gases is 0.807 atm + 0.193 atm = 1.000 atm.

The Total Pressure Exerted by a Mixture of 1