A tank contains 36.5 g of O₂ and 46.4 g of N₂ at a pressure of 3.64 atm. What is the pressure of O₂ in the tank (in atm) ?

Partial pressure O₂ = 1.49 atm

Explanation:

We can solve this, by the mole fraction concept.

Mole fraction = Moles of gas / Total moles

We can also define mole fraction as: Partial pressure of a gas / Total pressure

Total moles = Moles of O₂ + Moles of N₂

36.5 g. 1 mol / 32g + 46.4 g. 1mol / 28g = 2.79 moles

1.14 moles O₂ + 1.65 moles N₂ = 2.79 moles

Partial pressure O₂ / Total pressure = Moles of O₂ / Total moles

Partial pressure O₂ = (Moles of O₂ / Total moles). Total pressure.

We replace: (1.14 mol / 2.79 mol). 3.64 atm = 1.49 atm

Partial pressure O₂ = 1.49 atm