PV = nRT (where P = pressure; V = volume; n = number of moles; R = gas constant; T = Temperature)
Moles of He = mass of He ÷ molar mass of He = 10 g ÷ 4 g/mol = 2.5 mol
Now, based on the formula above P = (nRT) ÷ V
P = (2.5 mol × (0.082 L · atm/mol · K) × 233 K) ÷ 73 L ≈ 0.65 atm
