Pure Substances and Mixtures: Mechanism
≈ 25 minMechanism
Follow the mechanism step by step and distinguish what causes the change from what is merely observed.
This extension applies that lens specifically to Pure Substances and Mixtures.
All the matter around you — anything that has mass and takes up space — is either a pure substance or a mixture.
- A pure substance has a fixed composition throughout: every part is the same. Distilled water and pure copper are pure substances.
- A mixture is two or more substances physically combined, in any ratio, that keep their own properties. Sea water, air and a cup of rooibos are mixtures.
Mixtures are further split by how uniform they are:
- Homogeneous (a solution): one visible phase, evenly mixed — you cannot see the parts. Salt fully dissolved in water; the air you breathe.
- Heterogeneous: you can see (or separate out) the different parts. Sand in water; a bowl of chakalaka.
Chemistry — Grade 10 — Mechanism: Which of these is a pure substance?
Chemistry — Grade 10 — Mechanism: Salt fully dissolved in water is best described as a…
Chemistry — Grade 10 — Mechanism: Give a one-word classification (homogeneous or heterogeneous) for a glass of water with sand at the bottom.
Name the original topic being extended by this mechanism lesson.
Which statement is the best evidence-led starting point for Pure Substances and Mixtures: Mechanism?