If a substance decomposes, it has undergone:
physical change
chemical change
phase change

Question

anonymous · Answer

Why is this in the math section?

anonymous · Answer

mmmmm i would say physical  but wat is phase change if i may ask?

anonymous · Answer

It is chemical, anyways.

anonymous · Answer

chemical how?

anonymous · Answer

Chemical

anonymous · Answer

i would say a close tie between physical and chemical, if the actual chemical composition changes within decomposition it can be classified as chemical, if its physical properties (color, texture, shape etc.) then it could be classified as a physical change. If it changes, at any point, its state (solid, liquid, gas) then its a phase change.

anonymous · Answer

but chemical is more like it i now see the sense thanx zhill