Question

The density of a gas is 1.43 g/l at stp. what is its molar mass

Answer 1

So instead of 1.43 g/mol , you should have 1.43 g/L , i.e. 1 L of this gas has a mass of 1.43 g at STP conditions. Now, you were probably taught that 1 mole of any ideal gas occupies 22.4 L at STP conditions, which back in the day were defined as a temperature of 0∘C and a pressure of 1 atm .

Answer 2

Given:

Density = 1.63 g / L

STP

To find:

Molar mass

Solution:

By Avogadro's law,  

"One mole of gas at STP occupies 22.4 litres"

Hence,

It applies the same for the molar mass also.

And so,

Molar mass = Density * 22.4

1.43 * 22.4  

Molar mass = 32.032 g