Lesson Plan: 3C.1.01

Hamble Lesson Observation Plan
Learning About
What is the difference between pure and impure?
Keywords:
  • mixture (1)
  • element (1)
  • atom (1)
  • Impure (1)
  • Pure: (1)
Memory Anchor:
Method Precise Learning Objective Linked Question / Activity
(Designed for maximum working out)		 Stepping Stones Pitstop Check
(Thinking Map)
W A pure substance contains only what it is labelled as. It is not contaminated with something unexpected eg food grade chemicals. What is a 'pure substance'?

Does a pure substance mean: - contains only one type of chemical eg 24ct Gold OR: - only contains what you it says on the label? eg HCl (aq), Saline Construct 'Double Bubble' for example chemicals.
T A trace substance is chemical found in very small amounts. These may make substances impure. What is a trace substance?
D Pure substances can be identified by being unable to separate them. How can we identify a pure substance from an impure?

Circus of labelled substances: - Tap water - Aluminium - (Clean) Sand - Table Salt - Pond water - Sea water - Saline - Hydrochloric Acid - White chalk rock - Bronze (or other alloy) - Rusty nail - Steel nail - Distilled Witchazel - Deionised water Students identify if they are pure or not in table and give a reason. Then show formulae or constituent parts, do they change their minds? Brainstorm how we could tell if something is pure: Does it look like there are small amounts of different chemicals? Can it be separated into different chemicals? Is there a plus in the chemical formula for the substance?
Links To the Big Ideas
ForcesParticlesEnergyCells