Melting of wax is a physical change but burning of wax is a chemical change. Explain, why?

Define chemical change.

Define physical change.

Distinguish physical change and chemical change.

Classify the following as chemical or physical changes rusting of almirah.

Classify the following as chemical or physical changes burning of paper and wood.

Classify the following as chemical or physical changes melting of butter in a pan.

Classify the following as chemical or physical changes cutting of trees.

Classify the following as chemical or physical changes passing of electric current, through water and the water breaking down into hydrogen and oxygen gases.

If the mass of a body is halved and its velocity doubled, its momentum will not change. Explain.