melting of wax is a physical change as burning of candle is a chemical change. Why????
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Candle is made up of a solid block of wax with a wick embedded in it.
1) Physical Change
When candle is lit, the heat of the flame melts the solid wax to liquid wax. This signifies a physical change from solid state to liquid state. Also, as the wax melts, the size of the candle decreases. It then solidifies and takes a different shape.
2) Chemical Change
The wax acts as a fuel when we light the candle and is basically carbon. The carbon combines with oxygen to form another chemical substance, carbon dioxide and water. Also the unburnt carbon is deposited as black substance called soot. This signifies a chemical change.