Answer:
3.94 g
Step-by-step explanation:
At STP , 1 mol of N₂ gas occupies a volume of 22.4 L at STP.
molar mas of N₂ is 28 g/mol
1 mol of N₂ has a mass of 28 g.
a volume of 22.4 L is occupied by 28 g
therefore 3.15 L of volume is occupied by - 28 g / 22.4 L x 3.15 L = 3.94 g
the mass of 3.15 L of N₂ gas is - 3.94 g