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