What is the mass of 3.15 liters of N2 gas at STP?

2.86 grams

3.21 grams

3.94 grams

4.06 grams

3.94 g

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