EasyChemistryHigh School (9–10)GeneralChemical Reactions › Chemical EquationsChemical Reactions › Types of Chemical ReactionsConceptual
Say whether each change is physical or chemical.
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 change is physical or chemical.
- cutting paper, (b) burning paper, (c) cooking an egg, (d) melting butter, (e) digesting food, (f) mixing sand with water.
Need a reminder? The key ideaShow
In a chemical change, new substances form. Signs: a gas is given off, the colour changes, a precipitate forms, the temperature changes, or the state changes. A physical change, such as melting or dissolving, makes no new substance.
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. Physical. (a) cutting paper, (d) melting butter and (f) mixing sand with water make no new substance.
Step 2. Chemical. (b) burning paper, (c) cooking an egg and (e) digesting food make new substances that cannot easily be turned back.
Answer: physical: a, d, f. Chemical: b, c, e.
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