Question

When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.

Answer 1

When the candle burns,

wax $⟶{CO}_2+$ heat $+$ light

(vapours)

This is a chemical change, it can't be reversed. Whereas, melting of wax is a physical change.

${wax}_{\left(e\right)}\rightleftharpoons wax\left(solid\right)$

When molten wax cools it solidifies again.

Another example of a process in which both physical and chemical changes take place is the digestion of food.

Physical change $⟶$Breaking down of larger food particles into smaller particles

Chemical change $⟶$Digestion of food