Dear Student
When a candle burns, wax in the candle melts and is then vaporised as it is drawn up the wick.
Melting and vaporisation are physical changes.
The wax vapours then burn at the wick to leave behind soot and water vapour, while emitting heat and light. The burning of wax vapours is a chemical change. Thus, wax undergoes both physical and chemical changes when a candle burns.
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