Mixture of H2...

Question

A mixture of 1.00 g H2 and 1.00 g He is placed in a 1.00 L container at 27 Celsius. Calculate the partial pressure of each gas and the total pressure.

Answer 1

moles H₂ = 1.00 g x 1 mole/2.00 g = 0.500 moles H₂

moles He = 1.00 g x 1 mole/4.00 g = 0.250 moles He

Total moles of gas = 0.500 mol + 0.250 mol = 0.750 moles

mole fraction H₂ = 0.500/0.750 = 0.667

mole fraction He = 0.250/0.750 = 0.333

Total pressure = P

PV = nRT and P = nRT/V

P = (0.750 mol)(0.0821 Latm/Kmol)(300K)/1.00 L

P = 18.47 atm = Total Pressure = 18.5 atm

Partial pressure of H₂ = 0.667 x 18.5 atm = 12.3 atm

Partial pressure of He = 0.333 x 18.5 atm = 6.16 atm