What this topic covers
The syllabus points for Topic 3, with every question in the bank filed under exactly one of them. Each opens the bank filtered to that point.
- 3.1Formulae116 questions
- State the formulae of the elements and compounds named in the subject content
- Define the molecular formula of a compound as the number and type of different atoms in one molecule
- Deduce the formula of a simple compound from the relative numbers of atoms present in a model or a diagrammatic representation
- Construct word equations and symbol equations to show how reactants form products, including state symbols
- Define the empirical formula of a compound as the simplest whole number ratio of the different atoms or ions in a compound
- Deduce the formula of an ionic compound from the relative numbers of the ions present in a model or a diagrammatic representation or from the charges on the ions
- Construct symbol equations with state symbols, including ionic equations
- Deduce the symbol equation with state symbols for a chemical reaction, given relevant information
- 3.2Relative masses of atoms and molecules52 questions
- Describe relative atomic mass, Ar, as the average mass of the isotopes of an element compared to 1/12th of the mass of an atom of 12C
- Define relative molecular mass, Mr, as the sum of the relative atomic masses. Relative formula mass, Mr, will be used for ionic compounds
- Calculate reacting masses in simple proportions. Calculations will not involve the mole concept
- 3.3The mole and the Avogadro constant132 questions
- State that concentration can be measured in g / dm3 or mol / dm3
- State that the mole, mol, is the unit of amount of substance and that one mole contains 6.02 × 1023 particles, e.g. atoms, ions, molecules; this number is the Avogadro constant
- Use the relationship amount of substance (mol) = mass (g) molar mass (g / mol) to calculate: (a) amount of substance (b) mass (c) molar mass (d) relative atomic mass or relative molecular / formula mass (e) number of particles, using the value of the Avogadro constant
- Use the molar gas volume, taken as 24 dm3 at room temperature and pressure, r.t.p., in calculations involving gases
- Calculate stoichiometric reacting masses, limiting reactants, volumes of gases at r.t.p., volumes of solutions and concentrations of solutions expressed in g / dm3 and mol / dm3, including conversion between cm3 and dm3
- Use experimental data from a titration to calculate the moles of solute, or the concentration or volume of a solution
- Calculate empirical formulae and molecular formulae, given appropriate data
- Calculate percentage yield, percentage composition by mass and percentage purity, given appropriate data
Learning objectives from the Cambridge 0620 syllabus 2026–28:CoreSupplement (Extended only)
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