Relative atomic masses (ArA_rAr): He=4\text{He} = 4He=4, C=12\text{C} = 12C=12, N=14\text{N} = 14N=14, O=16\text{O} = 16O=16
Which sample contains the greatest number of particles?
28 g28\ \text{g}28 g of nitrogen, N2\text{N}_2N2
48 g48\ \text{g}48 g of oxygen, O2\text{O}_2O2
66 g66\ \text{g}66 g of carbon dioxide, CO2\text{CO}_2CO2
4.0 g4.0\ \text{g}4.0 g of helium, He\text{He}He
40 exam-style questions on AQA GCSE Chemistry 3.2 Use of amount of substance in relation to masses of pure substances, covering 3.2.1 Moles, 3.2.2 Amounts of substances in equations, 3.2.3 Using moles to balance equations, 3.2.4 Limiting reactants, 3.2.5a Concentration of solutions, and 3.2.5b Relating mass, volume and concentration. Each one has a worked solution and a mark scheme showing where the marks go.