Question

Classify the following into physical or chemical change :(i) burning of a candle(ii) freezing of water(iii) mixing of iron filings and sand.(iv) fading of clothes

Answer 1

A chemical change is a change in which something new is formed (irreversible). The starting materials change into an entirely different substance or substances. This new substance has a different chemical composition than the starting materials. while ​Physical Change is a change in which a substance changes form but its chemical composition is same.
1) Burning of candle - chemical change as some of the candle is changed into gases and heat. Also it is a physical change ,as it leaves the solid product.
2) freezing of water - Physical change
3) mixing of iron fillings and sand - Physical change
4) fading of clothes - chemical change as the dye has changed its colour.