Question

A gas of mass 32g has a volume of 20L at STP. Calculate the gram molecular weight of the gas.

Answer 1

Step 1: Given data

Mass of the gas is $32\mathrm{g}$

Volume of the gas is $20\mathrm{L}$

Step 2: Finding the number of moles:

The number of moles of the gas is $=\frac{\mathrm{volume}\mathrm{of}\mathrm{the}\mathrm{gas}}{\mathrm{Volume}\mathrm{occupied}\mathrm{by}\mathrm{the}\mathrm{gas}\mathrm{at}\mathrm{STP}}=\frac{20}{22.4}=0.89\mathrm{mol}$

Step 3: Calculating the gram molecular weight:-

The gram molecular weight of the gas is $=\frac{\mathrm{Mass}\mathrm{of}\mathrm{the}\mathrm{gas}}{\mathrm{Number}\mathrm{of}\mathrm{moles}\mathrm{of}\mathrm{the}\mathrm{gas}}=\frac{32}{0.89}=35.955\approx 36\mathrm{g}$

Therefore, the gram molecular weight of the gas is $36\mathrm{g}$