Question

A deep-sea diver uses a gas cylinder with a volume of 10.0 L and a content of 51.0 g of O2 and 33.3 g of He.

Part A

Calculate the partial pressure of each gas and the total pressure if the temperature of the gas is 18 ∘C.

Express the pressures in atmospheres to three significant digits separated by commas.

PO2, PHe, Ptotal =		atm

Answer 1

According to Ideal gas equation.

PV = nRT

n = sum of the moles of O2 and He.

moles of O2 = 51/32 = 1.594    ; moles of He = 33.3/4 = 8.325    ; total moles of gases = 1.594+8.325 = 9.919

Ptotal = nRT/V

          = (9.919*0.0821*291)/10

          = 23.697 atm

Partial pressure of O2 = molefraction of O2 *Ptotal

                                   = (1.594/9.919)*(23.697)

                                   = 3.808 atm

partial pressure of He = molefraction of He *Ptotal

                                   = (8.325/9.919)*(23.697)

                                   = 19.889 atm