Copper sulfate is a compound. Describe four ways in which a compound differs from a mixture.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
A compound has a fixed composition, whereas a mixture has a variable composition.
The properties of a compound are different from those of its constituent elements, whereas the properties of a mixture are similar to those of its components.
Elements in a compound are chemically joined or bonded together, whereas substances in a mixture are not chemically combined.
A compound can only be separated into its elements by chemical methods, whereas a mixture can be separated by physical methods.
The properties of a compound are different from those of its constituent elements, whereas the properties of a mixture are similar to those of its components.
Elements in a compound are chemically joined or bonded together, whereas substances in a mixture are not chemically combined.
A compound can only be separated into its elements by chemical methods, whereas a mixture can be separated by physical methods.
Examiner tips
- Use the word "fixed" for composition, "variable" for mixture. Mention "chemical bonds" vs "no chemical bonds". State separation methods: chemical vs physical. Keep each point short and to the point.
Common mistakes
- Confusing the definition of a compound with a mixture. Using vague terms like "different" without specifying fixed or variable composition. Forgetting to mention the role of chemical bonds or separation methods.
Mark scheme (4 marks)
- A compound has a fixed composition / definite ratio of elements, whereas a mixture has a variable composition
- The properties of a compound are different from the properties of its constituent elements, whereas the properties of a mixture are similar to those of its components
- Elements in a compound are chemically joined / bonded together, whereas substances in a mixture are not chemically combined
- A compound can only be separated into its elements by chemical methods, whereas a mixture can be separated by physical methods
Key terms in this question
Related
- All Cambridge International IGCSE Chemistry (0620) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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