Question

Prove that the molar mass of a gas is directly proportional to it's Density at constant T and P (Temperature and Pressure)

Please answer this question????

Answer 1

Answer:

PV = nRT

= m/M RT ( No of moles = Mass / Molar mass )

Now rearrange ,

m/V = PM / RT (P,T,R are constant)

m/V is density

Hence,

d = PM/RT

Density is directly proportional to the Molar

mass (M).

Hope this helps you.

Answer 2

Answer:

We know the ideal gas equation,

                          PV=nRT   (n=no. of moles)

                          PV=(m/M)RT  (∵n=m/M)(M=molar mass)

                            P=(m/VM)RT

                            P=(d/M)RT (∵d=m/V)

                           M=dRT/P

     Taking T and P constant,

                        ∴M∝d

 Hence proved.

Hope it helps you.