Concentration | GCSE Chemistry

Quantitative chemistry

Lesson overview

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

Focussolution concentration calculations

Time45-60 minutes

EquipmentPeriodic table, calculator and notebook.

Practical linksolution preparation and dilution accuracy

Maths tagsg/dm3, mol/dm3 and unit conversion

What you will learn

Describe the key chemistry ideas behind concentration of solutions.
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

Concentration of solutions is part of GCSE Chemistry because it helps explain particles, substances, reactions or practical evidence.
Use concentration and solution accurately, not just as remembered keywords.
This lesson includes the model steps, key data habits and answer checks needed to study solution concentration calculations without relying on an external worksheet.
When data appears, show working clearly and use g/dm3, mol/dm3 and unit conversion.

Concentration in solutions infographic

Illustrated GCSE Chemistry infographic showing dilute and concentrated solutions, concentration formulae, dm3 conversions, dilution and a worked g per dm3 example. — Use this infographic to connect solute particles, concentration formulae, dm3 conversions, dilution and unit checks.Download visual

Concentration practice set

Use the worked examples and practice questions on this page as a complete study task: learn the concentration and solution meanings, summarise the infographic in your own words, then answer the questions using the data, equations and observations given here. Check every answer for g/dm3, mol/dm3 and unit conversion.

Clear explanation

Concentration of solutions is built around solution concentration calculations. Start by learning what concentration and solution 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 g/dm3, mol/dm3 and unit conversion. For written explanations, include the specific chemistry reason rather than a memorised topic sentence.

Worked examples

Concentration: explaining the model

Start with the first relevant idea: Concentration = amount / volume.

Then connect it to the next part of the chemistry: Convert cm3 to dm3 by dividing by 1000.

Finish with the result or explanation: Keep g/dm3 and mol/dm3 units separate.

Answer: A complete answer links these steps in order and uses concentration, solution, dm3 accurately.

Concentration: using evidence

Use this evidence or method detail: solution preparation and dilution accuracy.

Identify the useful data, observation or apparatus detail before writing the explanation.

Process the information with g/dm3, mol/dm3 and unit conversion.

Finish by linking the result to concentration and solution.

Answer: A strong answer gives the evidence, any working, then a chemistry explanation using solution concentration calculations.

Quick checks

Choose an answer, then check your thinking.

1. Which statement is a useful first step for concentration?

Write the keyword without a definition Change the formulae to avoid hard working Concentration = amount / volume

2. Which detail makes the answer specific rather than vague?

solution preparation and dilution accuracy A topic title by itself A single keyword with no explanation

Practice questions

Question 1

Define concentration in the context of concentration of solutions.

Reveal answer and marking guidance

Answer: concentration is a key idea in solution concentration calculations; define it using the exact particle, structure, reaction or observation language from the lesson.

Marking: Credit a precise topic definition, not just the keyword repeated.

Question 2

Use the infographic to describe the main sequence in Concentration.

Reveal answer and marking guidance

Answer: Concentration = amount / volume -> Convert cm3 to dm3 by dividing by 1000 -> Keep g/dm3 and mol/dm3 units separate.

Marking: Credit the correct order and a clear chemistry link between steps.

Question 3

What specialist term or calculation habit is important for Concentration?

Reveal answer and marking guidance

Answer: A relevant answer should use terms such as concentration, solution, dm3, dilution and calculation habits such as g/dm3, mol/dm3 and unit conversion.

Marking: Credit a topic-relevant term with a reason for using it.

Question 4

A student writes: 'concentration is involved.' Add the missing chemistry detail.

Reveal answer and marking guidance

Answer: A stronger answer uses solution accurately and adds evidence from the model: Concentration = amount / volume then Convert cm3 to dm3 by dividing by 1000.

Marking: Credit precise topic language plus evidence from the model, data or practical context.

Practice ladder

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

ApplicationApply concentration of solutions 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

Describing the model steps without using concentration or solution to explain the chemistry behind them.
Forgetting g/dm3, mol/dm3 and unit conversion when they matter.
Mixing up atoms, ions, molecules and compounds.
Writing a memorised sentence about dm3 that does not match the substances in the question.

Extension challenge

Create a six-line revision card for concentration of solutions: two definitions, one infographic detail or equation line, one equation or data check, one common mistake, and one complete explanation sentence using concentration, solution, dm3.

Reveal answer

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