Salts | GCSE Chemistry

Chemical changes

Lesson overview

This lesson introduces the core chemistry idea, the useful equipment and the calculation or data skills used on this page.

Focuspreparing soluble salts

Time45-60 minutes

EquipmentNotebook, calculator, safety notes and any school practical sheet supplied by your teacher.

Practical linksalt preparation is a useful practical method for learning neutralisation, filtration and crystallisation

Maths tagsmass, volume, filtration and crystallisation observations

What you will learn

Describe the key chemistry ideas behind making salts by neutralisation.
Use precise GCSE command-word language in explanations.
Apply the idea to unfamiliar substances, data or practical contexts.
Check answers using units, state symbols, observations or balanced equations where relevant.

Core knowledge

A salt forms when hydrogen ions in an acid are replaced by metal ions or ammonium ions.
Hydrochloric acid makes chlorides, sulfuric acid makes sulfates, and nitric acid makes nitrates.
To make a soluble salt from an acid and insoluble base, add excess solid, filter, evaporate and crystallise.
Excess solid shows all the acid has reacted.
Filtration removes unreacted insoluble solid before crystallisation.

Preparing soluble salts infographic

Illustrated GCSE Chemistry infographic showing preparation of soluble salts using excess insoluble solid, filtration, crystallisation, word equations and safety checks. — Use this infographic to connect salt preparation reactants with neutralisation, filtration, crystallisation and naming the salt from ions.Download visual

Practical link

Add insoluble solid until some remains.
Filter off excess solid.
Evaporate gently; do not boil to dryness.
Dry crystals with filter paper.

Salts practice set

Use the worked examples and practice questions on this page as a complete study task: learn the salt and filtration meanings, summarise the infographic in your own words, then answer the questions using the data, equations and observations given here. Check every answer for mass, volume, filtration and crystallisation observations.

Clear explanation

Making salts by neutralisation is built around preparing soluble salts. Start by learning what salt and filtration mean, then connect them to the sequence in the infographic.

The key GCSE skill is to move from evidence to explanation: name the observation, data trend, particle model, structure or reaction, then explain why it supports the conclusion.

For calculation or data work, show mass, volume, filtration and crystallisation observations. For written explanations, include the specific chemistry reason rather than a memorised topic sentence.

Worked examples

Core example: naming a salt

Copper oxide provides copper ions.

Sulfuric acid forms sulfate salts.

Combine metal name and salt ending.

Answer: Copper sulfate.

Extension example: copper sulfate equation

Acid + metal oxide -> salt + water.

Use formulae CuO and H2SO4.

Check atoms balance.

Answer: CuO + H2SO4 -> CuSO4 + H2O.

Quick checks

Choose an answer, then check your thinking.

1. Which acid makes nitrate salts?

Hydrochloric acid Sulfuric acid Nitric acid

2. Why filter after adding excess copper oxide?

To remove unreacted solid To remove dissolved salt To neutralise water

Practice questions

Question 1

Name the salt from magnesium and hydrochloric acid.

Reveal answer and marking guidance

Answer: Magnesium chloride.

Marking: Credit metal name plus chloride.

Question 2

Give the word equation for zinc oxide and nitric acid.

Reveal answer and marking guidance

Answer: zinc oxide + nitric acid -> zinc nitrate + water.

Marking: Credit correct reactants and products.

Question 3

Why add excess insoluble base?

Reveal answer and marking guidance

Answer: To make sure all the acid reacts; excess solid can be filtered off.

Marking: Credit full reaction and filtration.

Question 4

Stretch: Why not use excess sodium hydroxide and filtration to make sodium chloride?

Reveal answer and marking guidance

Answer: Sodium hydroxide is soluble, so excess alkali remains in solution and cannot be filtered off.

Marking: Credit soluble excess reagent.

Practice ladder

FluencyRecall the key definition, symbol, structure, equation or observation.

ApplicationApply making salts by neutralisation to unfamiliar substances, practicals or data.

Practical interpretationUse evidence, method quality, uncertainty or conclusion wording where asked to evaluate.

Maths skillUse units, ratios, graphs and significant figures accurately.

Answers and marking guidance

The exact practice answers are hidden under each question so you can try first. Marks come from using the correct chemistry model, choosing the right equation where needed, keeping units with values, and explaining changes with precise words such as particles, ions, bonds, energy, rate, evidence and uncertainty.

Common mistakes

Choosing the salt ending from the metal.
Boiling to dryness.
Trying to filter off a soluble excess reagent.
Forgetting water is made with metal oxides/hydroxides.

Extension challenge

Create a six-line revision card for making salts by neutralisation: two definitions, one infographic detail or equation line, one equation or data check, one common mistake, and one complete explanation sentence using salt, filtration, crystallisation.

Reveal answer

Example answer: A complete response names the chemistry model, uses accurate units or observations, and explains why the evidence supports the conclusion.