Purity and impurities
What Purity and impurities means in Chemistry GCSE, as defined for AQA.
Definitions of Purity and impurities
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Reference: AQA
A pure substance contains only one substance, while an impurity is something else present that lowers the melting point and raises the boiling point.
Impurities usually lower the melting point and raise the boiling point, so melting and boiling points can be used to check purity.
Topics that use Purity and impurities
- Pure substances (AQA GCSE)
- The three states of matter (AQA GCSE)
Related terms
- Melting and boiling points
- Boiling
- Changes of state
- Comparing melting and boiling points
- Comparison with known values
- Context in scientific language
- Effect of impurities on physical properties
- Energy transfers during changes of state
Using Purity and impurities in the exam
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