MediumChemistryHigh School (9–10)GeneralMixtures and Solutions › Elements, Compounds and ChangesConceptualBoard Exam

For each, name the sign of a chemical change, and the new substance if you can…

Try it on paper first. A hint, the key idea and the worked solution are here when you need them.

For each, name the sign of a chemical change, and the new substance if you can.

Baking soda is added to vinegar, and it fizzes.
A slice of potato turns blue-black when iodine is dropped on it.
A silver spoon slowly turns black.
A gas flame on a stove gives out heat and light.

Need a reminder? The key ideaShow

A physical change makes no new substance (melting, dissolving, breaking). A chemical change makes new substances (burning, rusting, cooking). Gas, colour, smell, heat, light and a new solid are clues; the test is always: is a new substance made?

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.

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