The molecular weight (molar mass) of any gas is the mass of one particle of that gas multiplied by Avogadro's number (6.02 x 1023).
Explanation:
How do you find the molar mass of a gas?
First the ideal gas law will be used to solve for the moles of unknown gas (n). Then the mass of the gas divided by the moles will give the molar mass.
The periodic law states “When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties