Form 4 Chemistry The mole, Avogadro constant and molar mass Exercise Worksheet 1. Calculate the number of atoms in the following substance. (Relative atomic masses: H = 1.0, C = 12.0, N = 14.0, O = 16.0, Na = 23.0, Al = 27.0, S = 32.1) (a) 2 moles of sodium metal (b) 2 g of oxygen gas (c) 1.5 moles of nitrogen dioxide (d) 0.5 mole of sodium carbonate (e) 22 g of aluminum sulphate 2. Find the mass of the following substances. (Relative atomic masses: Ca = 40.1, H = 1.0, O = 16.0, Mg = 24.3, Na = 23.0) (a) 0.5 mol of calcium hydroxide (b) 3 mol of oxygen gas (c) 1 water molecule (d) 1 Mg atom (e) 3.01 x 1023 Na atoms 1|P age