Question

A deep-sea diver uses a gas cylinder with a volume of 10.0 L and a content of 51.0 g of O2and 33.6 g of He.

Calculate the partial pressure of each gas and the total pressure if the temperature of the gas is 21 ∘C.

Answer 1

1) for O2

Molar mass of O2 = 32 g/mol

mass of O2 = 51.0 g

we have below equation to be used:

number of mol of O2,

n = mass of O2/molar mass of O2

=(51.0 g)/(32 g/mol)

= 1.594 mol

we have:

V = 10.0 L

n = 1.5938 mol

T = 21.0 oC

= (21.0+273) K

= 294 K

we have below equation to be used:

P * V = n*R*T

P * 10 L = 1.5938 mol* 0.08205 atm.L/mol.K * 294 K

P = 3.8447 atm

Answer: 3.84 atm

2) for He

Molar mass of He = 4.003 g/mol

mass of He = 33.6 g

we have below equation to be used:

number of mol of He,

n = mass of He/molar mass of He

=(33.6 g)/(4.003 g/mol)

= 8.394 mol

we have:

V = 10.0 L

n = 8.3937 mol

T = 21.0 oC

= (21.0+273) K

= 294 K

we have below equation to be used:

P * V = n*R*T

P * 10 L = 8.3937 mol* 0.08205 atm.L/mol.K * 294 K

P = 20.2 atm

Answer: 20.2 atm

3)

total pressure = 3.84 atm + 20.2 atm

= 24.0 atm

Answer: 24.0 atm