Topic 1: Stoichiometry - 1.1 Introduction to the particulate nature of matter and chemical change

Nature of science:

Making quantitative measurements with replicates to ensure reliability - definite and multiple proportions. 3.1


Essential idea: Physical and chemical properties depend on the ways in which different atoms combine.

Atoms of different elements combine in fixed ratios to form compounds, which have different properties from their component elements. Mixtures contain more than one element and/or compound that are not chemically bonded together and so retain their individual properties.

Mixtures are either homogeneous or heterogeneous.

Applications and skills

Deduction of chemical equations when reactants and products are specified.

Application of the state symbols (s), (l), (g) and (aq) in equations.

Explanation of observable changes in physical properties and temperature during changes of state.


Balancing of equations should include a variety of types of reactions.

Names of the changes of state-melting, freezing, vaporization (evaporation and boiling), condensation, sublimation and deposition-should be covered.

The term "latent heat" is not required.

Names and symbols of elements are in the data booklet in section 5.