Question

..why is the burning of LPG gas from a cylinder considered both a physical and chemical change..​

Answer 1

Chemical change: Burning of vapours of wax to give carbon dioxide, heat and light. LPG is another example in which physical change occurs when LPG comes out of cylinder and is converted from liquid to gaseous state and a chemical change occurs when gas burns in air.

Answer 2

Answer:

Burning of LPG involves both physical and chemical changes because when LPG comes out of cylinder and is converted from liquid to gaseous state it is a physical change.When the gas burns in air it is a chemical change.Similarly ,burning of candle is a physical as well as a chemical change because solid wax changes to liquid form and its form can be regained hence it is a physical change but burning of wax is a chemical change.