Cambridge IGCSE Chemistry

3.3The mole and the Avogadro constant

The mole and the Avogadro constant in Cambridge IGCSE Chemistry: what the syllabus expects you to know, the learning objectives and how to practise.

Subtopic142 practice questions7 lessons

Overview

Statement 1 is Core; all mole calculations (statements 2 to 8) are Supplement.

What the syllabus expects you to be able to do.

3.3.1State that concentration can be measured in g/dm³ or mol/dm³.
3.3.2Supplement: state that the mole (mol) is the unit of amount of substance and that one mole contains 6.02 × 10²³ particles (atoms, ions or molecules), the Avogadro constant.
3.3.3Supplement: use amount of substance (mol) = mass (g) ÷ molar mass (g/mol) to calculate an amount, a mass, a molar mass, a relative atomic or molecular/formula mass, or (with the Avogadro constant) a number of particles.
3.3.4Supplement: use the molar gas volume, 24 dm³ at room temperature and pressure (r.t.p.), in calculations on gases.
3.3.5Supplement: calculate reacting masses, limiting reactants, volumes of gases at r.t.p., volumes of solutions and concentrations in g/dm³ and mol/dm³, converting between cm³ and dm³.
3.3.6Supplement: use titration results to calculate the amount of solute, or the concentration or volume of a solution.
3.3.7Supplement: calculate empirical and molecular formulae from suitable data.
3.3.8Supplement: calculate percentage yield, percentage composition by mass and percentage purity from suitable data.

A sample question on this topic. Answer it, check it, then read the worked answer.

Practise with instant marking, see your mastery grow and get a study plan built around your exam date.