Calculate the mass of 0.1 mole of each of the following

(a) CaCO₃

(b) Na₂SO₄.10H₂O

(c) CaCl₂

(d) Mg

(Ca = 40, Na = 23, Mg =24, S = 32, C = 12, Cl = 35.5, O = 16, H = 1)

(a) Mass of 1 mole of CaCO₃

= Ca + C + 3O = 40 + 12 + (3 x 16) = 52 + 48 = 100 g

∴ Mass of 0.1 mole of CaCO₃ = 0.1 x 100 = 10 g

(b) Mass of 1 mole of Na₂SO₄.10H₂O

= 2Na + S + 4O + 10(2H + O) = (2 x 23) + 32 + (4 x 16) + 10(2 + 16) = 46 + 32 + 64 + 180 = 322 g

∴ Mass of 0.1 mole of Na₂SO₄.10H₂O = 0.1 x 322 = 32.2 g

(c) Mass of 1 mole of CaCl₂

= Ca + 2Cl = 40 + (2 x 35.5) = 40 + 71 = 111 g

∴ Mass of 0.1 mole of CaCl₂ = 0.1 x 111 = 11.1 g

(d) Mass of 1 mole of Mg = 24 g

∴ Mass of 0.1 mole of Mg = 24 x 0.1 = 2.4 g