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
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