Keshu

Physical changes require energy for processes like melting, or evaporation.

Physical changes often involve transitions between solid, liquid, gas

Solid-> liquid : ice melting

Liquid-> Gas: Water boiling

Solid-> Gas: Dry ice sublimation

Chemical changes produce substances with new chemical identities.

Most chemical changes cannot be reversed by physical means.

The chemical nature of the substance changes, eg: cooking a raw egg changes the proteins it cannot be turned back into a raw egg