The molecular mass of gas = 44 g/mol
Further explanation
Given
5.6 Liters of gas
11 gram of gas
Required
The molecular mass
Solution
STP = Standart Temperature and Pressure , 1 atm 273 K
At STP , 1 mol gas = 22.4 L
So mol of 5.6 Liters gas :
= 5.6 : 22.4
= 0.25 moles
The molecular mass of gas :
= mass : mol
= 11 g : 0.25 moles
= 44 g/mol