Identifying unknown substances (including magnesium)
I can conduct ion identification tests using flow charts, accurately record observations, and identify gases to ensure correct and safe lab practices.
Identifying unknown substances (including magnesium)
I can conduct ion identification tests using flow charts, accurately record observations, and identify gases to ensure correct and safe lab practices.
Lesson details
Key learning points
- Unique tests for each substance help minimise errors and ensure correct identification.
- Gas tests can be used to identify carbon dioxide, oxygen, hydrogen and ammonia.
- Observations and results should be recorded accurately for analysis during the practical.
- Flow charts break down complex activities into ordered sets of simpler steps, crucial for efficient ion identification.
Common misconception
All tests for ions are interchangeable and can be used in any order without affecting the outcome.
Clarify that each test is specific and must be conducted in a particular order to avoid interference. For example, testing for sulfates before halides can prevent false positives caused by overlapping precipitates, ensuring accurate identification.
Keywords
Precipitate - An insoluble solid formed when two solutions react together.
Ion - An ion is an atom or group of atoms with a positive or negative charge due to the loss or gain of electrons.
Cation - A positively charged ion.
Anion - A negatively charged ion.
Equipment
Test tubes, racks, Bunsen burner, test tube holders, AgNO₃, HNO₃, BaCl₂, HCl, NaOH, limewater, splints, distilled water, unknown samples (CaCl₂, CaSO₄, FeCl₂, K₂CO₃, KI), and flame test apparatus.
Content guidance
- Risk assessment required - chemicals
- 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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