What is the mass of:

(a) 1 mole of nitrogen atoms

(b) 4 moles of aluminium atoms?

(c) 10 moles of sodium sulphite (Na₂S0₃)?

(Atomic masses: N = 14 u, AI= 27 u, Na = 23 u, S = 32 u and 0 = 16 u)

(a) Mass of 1 mole of nitrogen atoms = Atomic mass of nitrogen atom

Atomic mass of nitrogen atom = 14u

Therefore, Mass of 1 mole of nitrogen atoms = 14 g

(b) Mass of 1 mole of Aluminium atoms = Atomic mass of Aluminium

Atomic mass of Aluminium = 27 u

Mass of 1 mole of aluminium atom = 27 g

Therefore, mass of 4 moles of aluminium atoms = 4 X 27 = 108 g

(c) Mass of 1 mole of sodium sulphite = Molecular mass of sodium sulphite (Na₂SO₃) in grams

Molecular mass of Na₂SO₃ in grams = Mass of 2Na + Mass of S +Mass of 3 '0'

= 2 X 23 + 32 + 3 X 16

= 46 + 32 + 48

= 126 g

Therefore, Mass of 10 moles of Na₂SO₃ = 126 x 10 g = 1260 g