Question

A sample of Ar gas at 35°C occupies a volume of 1.50 L at a pressure of 3.2 atm. How many moles of the gas are present in the sample?

Answer 1

The moles of the gas that are present in the sample is 0.1898 moles

calculation

• Use the Ideal gas equation

that is PV= nRT

where p ( pressure) = 3.2 atm

V( volume) = 1.50 L

n ( number of moles) =?

R ( gas constant)= 0.0821 atm.L/mol.K

T( temperature)= 35 +273 ==308 k

• make n the subject of the formula by diving both side by RT

n = Pv/RT

n is therefore= [3.2 atm x 1.50 L) / ( 0.0821 atm.L/mol.K x 308 K)= 0.1898 moles