Which property of physical changes explains why matter is conserved in a physical change?

1 Answer
Oct 13, 2016


Do you mean #"physical change"# or #"chemical change"#?


Mass is always conserved in a chemical change, which process involves involves the rearrangement of atoms and molecules. Of course most physical changes also conserve mass: when #10*g# of liquid water is frozen, you are left with #10*g# of solid ice.

Of course, there are also nuclear reactions (I am bit reticent, because I don't know whether I should put this under the #"physical"# umbrella). In nuclear fusion and fission, matter is not conserved, and can be converted into energy, with the result that the energy output/input dwarfs those observed in chemical reactions.