Question

What is the mass of 15.7 mol of Nitrogen gas (N2)​

Answer 1

1 mole of nitrogen weighs 28 g

15.7 mol = 15.7 * 28 = 439.6 g

Answer 2

Molar mass of N2 = 14×2=28g/mol

Moles of N2 =mass/molar mass

Mass of N2 = moles × molar mass

Mass of N2 = 15.7 × 28 = 439.6 kg