Diversity of Matter and Materials (Living and Non-living)
Diversity of Matter and Materials
This domain tests how confidently you classify matter as living or non-living, describe materials by their properties, and use the particle model to explain mixtures, separation and change. GTLE items often ask you to justify a classification, choose a separation method, or interpret a simple experiment.
Core rules and concepts
- Living things share measurable characteristics: cellular organisation, nutrition, respiration, excretion, response, movement, growth, reproduction and control. 'Dead' and 'non-living' are not synonyms: a dead tree was once living; a rock never was.
- Matter is either a pure substance (element or compound) or a mixture. Elements contain one kind of atom; compounds contain chemically combined elements in fixed ratios; mixtures can be separated by physical means.
- The particle model explains properties: particles in solids vibrate in fixed positions; liquids slide; gases move freely. Dissolving is not disappearance - particles spread between solvent particles, so mass is conserved.
- Separation depends on a difference in property: filtration (insoluble solid), evaporation/crystallisation (dissolved solid), simple distillation (solvent from solution), chromatography (dyes), magnetism (iron).
Worked example
A clear liquid is labelled 'pure water or salt solution'. Describe a sequence that decides safely. First, evaporate a small sample on a watch glass: a white residue indicates dissolved salt, so it is a mixture. If no residue remains, check boiling point: pure water boils sharply at 100 °C at normal pressure, while salt solution boils above 100 °C and over a range. Electrical conductivity is supporting evidence, not proof, because some pure substances also conduct when molten. Reasoning: each test targets a different property - residue tests non-volatile solute; boiling-point range tests purity.
Traps that cost marks
Calling air a compound (it is a mixture); saying sugar 'melts' when it dissolves; treating 'non-living' as 'dead'; choosing distillation to separate sand from water when filtration is simpler; forgetting that a compound has a fixed composition while a mixture does not.