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Chemical AnalysisDefinitions

Key Definitions

Part of Tests for Ions — GCSE Chemistry

This definitions covers Key Definitions within Tests for Ions for GCSE Chemistry. Revise Tests for Ions in Chemical Analysis for GCSE Chemistry with 20 exam-style questions and 14 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 7 of 14 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.

Topic position

Section 7 of 14

Practice

20 questions

Recall

14 flashcards

📖 Key Definitions

Precipitate: An insoluble solid formed when two solutions are mixed together. It appears as a cloudiness or solid particles settling out of solution.

Precipitation reaction: A reaction between two aqueous solutions that produces an insoluble product (precipitate). General form: A⁺(aq) + B⁻(aq) → AB(s)

Qualitative analysis: Chemical analysis that identifies WHAT substances are present (as opposed to quantitative analysis, which measures HOW MUCH is present).

Spectator ions: Ions that are present in solution during a reaction but do not take part in the reaction. They can be removed from the full ionic equation to give the net ionic equation.

False positive: A test result that incorrectly indicates the presence of a substance. Prevented in sulfate and halide tests by adding acid to remove interfering ions.

Keep building this topic

Read this section alongside the surrounding pages in Tests for Ions. That gives you the full topic sequence instead of a single isolated revision point.

All Ion Tests: Full ReferenceSequential Testing StrategyThe Detective's Chemistry ToolkitTesting for Metal Ions (Cations)

Practice Questions for Tests for Ions

Which reagents are used to test for carbonate ions in a solution?

  • A. Add barium chloride solution, then dilute HCl
  • B. Add dilute acid, then test the gas with limewater
  • C. Add silver nitrate solution, then dilute HNO3
  • D. Add sodium hydroxide solution and warm
1 markfoundation

Describe how sodium hydroxide solution can be used to distinguish between iron(II) ions and iron(III) ions in solution, including the expected observations.

3 marksstandard

Quick Recall Flashcards

What is a precipitation reaction?
A reaction where two soluble ionic compounds react to form an insoluble precipitate. General form: A⁺(aq) + B⁻(aq) → AB(s)
How do you test for sulfate ions (SO₄²⁻)?
Add barium chloride solution + dilute HCl. White precipitate of BaSO₄ forms. Equation: Ba²⁺ + SO₄²⁻ → BaSO₄(s)

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Sequential Testing Strategy