Question

What is the mass of 2.15 liters of N2 gas at STP?

Answer 1

Explanation: molar mass of N2=28

Volume occupied at stp=22.4 so 28/22.4=1.25 so mass nitrogen will be 56 multiply 1.25 =70g

Answer 2

Answer: 2.68 grams

Explanation:

According to avogadro's law, 1 mole of the substance occupies 22.4 liters at STP and contains avogadro's number $6.023\times 10^{23}$ of particles and weighs equal to its molecular mass.

1 mole of $N_2$ weighs 28 grams.

Also 1 mole of $N_2$ occupies 22.4 Liters.

Thus 22.4 L $N_2$ weigh = 28 grams

2.15 L of $N_2$ weigh =$\frac{28}{22.4}\times 2.15=2.68g$

Thus the mass of nitrogen gas is 2.68 grams.