Answer: In a physical change like melting of ice , energy is given to increase the molecular saperarion between the molecules, leading to liquid water and its physical state also changes but chemically it is still H2O, no change in identity.
During a chemical change mass does not changes but it chemical chane, it do, for ex in rusting of iron, the Fe2O3 cover is comparable to mass of ice if thin sheetvis used for rusting and also in burning of candle which is made of hydrocarbon has its mass lost into air
