When a candle burns, both physical and chemical changes occur. ... So, the melting of wax and vapourisation of melted wax are physical changes. Chemical Changes : The wax near flame burns and gives new substances like carbon dioxide, carbon soot, water vapour, heat and light.
When a candle burns, the oxygen in the air reacts and forms carbon dioxide. A new substance, the CO2 is formed. So it is a chemical change. When the candle melts, no new substance is formed and the molten wax can be again solidified and made into a candle and it is a reversible change.
