Are there changes in the physical and chemical properties of a substance when it undergoes a physical change? Is the same true for chemical changes?
Well, physical changes are LARGELY changes of state...
...i.e.. solid to liquid, liquid to gas...and vice versa. And certainly, density, mass per unit volume, changes markedly upon a phase change between a condensed phase, solid or liquid, and a gaseous phase. On the other hand, chemical changes involve the formation of new substances, and the making and breaking of strong chemical bonds....and had I a fiver for every time I said that I might have a £100-00..so I should not complain too much.