(e) Chemical formulae, equations and calculations

Write word equations and balanced chemical equations (including state symbols):

• for reactions studied in this specification
• for unfamiliar reactions where suitable information is provided.

Calculate relative formula masses (including relative molecular masses) (Mr) from relative atomic masses (Ar)

Know that the mole (mol) is the unit for the amount of a substance

Understand how to carry out calculations involving amount of substance, relative atomic mass (Ar) and relative formula mass (Mr)

Calculate reacting masses using experimental data and chemical equations

Calculate percentage yield

Understand how the formulae of simple compounds can be obtained experimentally, including metal oxides, water and salts containing water of crystallisation

Know what is meant by the terms empirical formula and molecular formula

Calculate empirical and molecular formulae from experimental data

Carry out calculations involving amount of substance, solution volume and concentration in mol/dm³.

Carry out gas-volume calculations using a molar gas volume of 24 dm³ mol⁻¹ (24 000 cm³ mol⁻¹) at room temperature and pressure.

Practical: know how to determine the formula of a metal oxide by combustion (e.g. magnesium oxide) or by reduction (e.g. copper(II) oxide)