A gaseous mixture is prepared by mixing 2 g of hydrogen ( H ₂ ) and 16 g of oxygen ( O ₂ ). If the total pressure of the mixture is 1.2 atm , what is the partial pressure of oxygen in the mixture?

Step-by-step solution

First, calculate the number of moles of each gas in the mixture: Number of moles of H ₂ = Given mass Molar mass = 2 g 2 g mol ⁻¹ = 1 mol Number of moles of O ₂ = 16 g 32 g mol ⁻¹ = 0.5 mol Total number of moles in the mixture = 1 + 0.5 = 1.5 mol Mole fraction of O ₂ ( x_ O ₂ ) = Moles of O ₂ Total moles = 0.5 1.5 = 1 3 According to Dalton's law of partial pressures: p_ O ₂ = x_ O ₂ p_ total p_ O ₂ = 1 3 1.2 atm = 0.4 atm Answer: 0.4 atm