EasyChemistryHigh School (9–10)GeneralMixtures and Solutions › Mixtures, Solutions and ColloidsConceptualBoard Exam
Say whether each is a pure substance or a mixture, and give a reason…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Say whether each is a pure substance or a mixture, and give a reason.
- Steam from a kettle
- Soft drink
- Sea water
- A copper wire
- Bronze
- Sugar
Need a reminder? The key ideaShow
A pure substance has one kind of matter and fixed properties, such as a sharp melting point. A mixture has two or more substances in any amounts; each keeps its own properties. A homogeneous mixture (a solution, an alloy, air) is the same all through; a heterogeneous one is not.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Pure substances. (a) Steam is only water, as a gas. (d) Copper is an element. (f) Sugar is one compound.
Step 2. Mixtures. (b) Soft drink is water with sugar, flavours and carbon dioxide. (c) Sea water has salts dissolved in water. (e) Bronze is an alloy of copper and tin.
Answer: (a), (d) and (f) are pure substances; (b), (c) and (e) are mixtures.
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