Why is the burning of a candle considered a chemical change?
Candles are made of wax and a long thread of cotton (called wick of the candle). While candle is burnt, the molten wax goes up through the thread and undergoes combustion to form carbon dioxide and water vapour. The ‘wick’ of the candle gets changed to a black mass. Over the process, heat and light energy is given out. It is not possible to (i) recover the burnt wax again, (ii) recover the thread again. Hence, the burning of a candle is a chemical change.
