Answer :
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
1 mole of nitrogen weighs 28 g
15.7 mol = 15.7 * 28 = 439.6 g
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