Chemical ChangesDefinitions

Key Definitions

Part of Making SaltsGCSE Chemistry

This definitions covers Key Definitions within Making Salts for GCSE Chemistry. Revise Making Salts in Chemical Changes for GCSE Chemistry with 20 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 8 of 13 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.

Topic position

Section 8 of 13

Practice

20 questions

Recall

20 flashcards

📖 Key Definitions

Crystallisation: The process of allowing a dissolved solid to form crystals as a solution cools or as water evaporates. Used to obtain a pure, dry solid salt from solution.

Filtration: Separating an insoluble solid from a liquid by passing the mixture through filter paper. The solid stays on the paper (residue); the liquid passes through (filtrate).

Evaporation: Heating a solution to drive off water as water vapour, concentrating the solution so that the dissolved solid (salt) crystallises on cooling.

Precipitation: The formation of an insoluble solid when two solutions are mixed. The insoluble solid is called a precipitate and is denoted by (s) in equations.

Excess: Adding more of one reactant than is needed to ensure the other reactant is completely used up. Excess insoluble reactant is removed by filtration.

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

Practice Questions for Making Salts

Which of the following is the correct method for making copper sulfate crystals from copper oxide and sulfuric acid?

  • A. Add excess copper oxide to acid, filter off unreacted solid, then evaporate to crystallise
  • B. Add excess acid to copper oxide, then boil to dryness
  • C. Use titration with an indicator to find the exact volumes, then repeat
  • D. Mix equal volumes of copper sulfate solution and sulfuric acid
1 markfoundation

Describe the steps involved in the required practical for preparing a pure, dry sample of copper sulfate crystals from copper oxide and dilute sulfuric acid.

4 marksstandard

Quick Recall Flashcards

What colour is copper sulfate?
Blue (as crystals and in solution)
What is crystallisation?
The process of forming solid crystals from a saturated solution

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