If a container holds 1mol of hydrogen, 2.5mol of helium, and 2mol of oxygen at a total pressure of 4atm, what is the partial pressure of the oxygen gas?

Partial pressure O₂ = 1.78 atm

Explanation:

We can apply the mole fraction to solve the question:

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

Total moles = 1 H₂ + 2.5 He + 2O₂ = 4.5 moles

2 mol O₂ / 4.5 mol = Partial pressure O₂ / 4 atm

(2 mol O₂ / 4.5 mol). 4 atm = Partial pressure O₂ → 1.78 atm

The partial pressure of oxygen is 1.45 atm

Explanation:

Step 1: Data given

Number of moles of hydrogen = 1 mol

Number of moles of helium = 2.5 mol

Number of moles of oxygen = 2 mol

Total pressure = 4 atm

Step 2: Calcualte total number of moles

Total number of moles = number of moles of hydrogen + number of moles of helium + number of moles of oxygen = 1 + 2.5 + 2 = 5.5 mol

Step 3: Calculate mol fraction of oxygen

Mol fraction oxygen = 2 mol / 5.5 mol = 0.3636

Step 4: Calculate partial pressure of oxygen

Partial pressure of oxygen = mol fraction of oxygen * total pressure

Partial pressure of oxygen = 0.3636 * 4 atm = 1.45 atm

The partial pressure of oxygen is 1.45 atm