Chemical reactions: precipitation
I can describe what happens during precipitation reactions, and write chemical equations to show these.
Chemical reactions: precipitation
I can describe what happens during precipitation reactions, and write chemical equations to show these.
Lesson details
Key learning points
- Precipitation reactions occur when two solutions combine to form an insoluble solid.
- The appearance of a precipitate is evidence that a chemical reaction has occurred.
- Precipitation reactions are important in water treatment, to remove unwanted substances from water.
- Precipitation reactions are used in qualitative analysis, to identify the presence of certain substances in a solution.
Common misconception
Pupils can struggle to understand that a solid is not always a large piece of a substance.
Show visually the difference between a transparent coloured solution e.g. copper sulfate solution and a coloured precipitate solution. Practice describing the difference between a white precipitate and a transparent colourless solution.
Keywords
Precipitation - The process where a precipitate is formed.
Precipitate - An insoluble solid formed when two solutions react together.
Aqueous solution (aq) - Formed when a substance is dissolved in water.
Insoluble - A way of describing a substance that will not dissolve in a particular solvent.
Chemical qualitative analysis - A chemical test that confirms the presence of a substance, it does not tell you how much of the substance is present.
Equipment
Lead nitrate, potassium iodide, beakers, filtration kit: conical flask, filter paper, funnel, solutions containing CU²⁺, Fe²⁺, Fe³⁺, Ca²⁺, Al³⁺, sodium hydroxide, test tubes and rack.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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Starter quiz
6 Questions
(s)
(l)
(g)
(aq)