Crystallisation
Crystallisation forms pure solid crystals as a hot saturated solution cools and the solute can no longer stay dissolved.
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Crystallisation forms pure solid crystals as a hot saturated solution cools and the solute can no longer stay dissolved.
- Heat to evaporate some water
- Cool slowly for larger crystals
- Filter and dry the crystals
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Crystallisation?
Within Chemistry, which covers atoms, bonding, reactions, the periodic table, organic chemistry and the chemistry of everyday life, this topic explains Crystallisation. Chemistry links what you can see in the lab to the particles and bonds behind it, so each topic here shows that link in a model.
Check that you can explain Crystallisation in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Crystallisation helps you explain why substances behave as they do, from cleaning products and food to medicines.
Crystallisation in detail
Crystallisation obtains solid crystals from a solution. Heat the solution to evaporate some of the solvent until it is saturated (a glass rod dipped in forms crystals when cooled), then leave it to cool slowly, so that crystals grow, then filter, wash with a little cold water and dry.
Slow cooling gives larger, purer crystals. The method is used to make salts such as copper sulfate and to purify solids by recrystallisation. Evaporating to dryness is not used for salts that decompose or contain water of crystallisation, such as blue copper sulfate crystals.
How the interactive helps you understand Crystallisation
Click a step, or use the Previous and Next buttons, to move through the sequence one stage at a time. Auto-play moves on for you.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Crystallisation.
Real-life uses and examples
- Link Crystallisation to everyday products such as cleaning agents, food and medicines.
- Read a chemical equation or diagram and work out what Crystallisation shows.
- Explain Crystallisation in an exam by linking the particles involved to what you observe.
Common mistakes to avoid
- Mixing up the names of substances or ions when you describe Crystallisation.
- Describing what happens without explaining the particles or bonds involved.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Crystallisation
What is Crystallisation?
Crystallisation forms pure solid crystals as a hot saturated solution cools and the solute can no longer stay dissolved.
What are the most important points about Crystallisation?
The main points are: Heat to evaporate some water; Cool slowly for larger crystals; Filter and dry the crystals.
Why is Crystallisation useful?
Understanding Crystallisation helps you explain why substances behave as they do, from cleaning products and food to medicines.
How can I practise Crystallisation?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Crystallisation?
Related topics in Chemistry include Chemistry of the Atmosphere Layers, Chemical Industry and Sustainability, Chemistry in Everyday Life.