What are five clues you would consider before diciding whether a change you observe is physical or chemical?

The 5 clues to a chemical change are:

1. energy (heat or light) is given off, or heat is absorbed
2. there is a precipitate (which means a solid has formed at the bottom of a solution)
3. the change is hard to reverse or irreversible
4. there are bubbles which means a gas is being released
5. the solution turns a different colour

To be 100% certain that it is a chemical change, at least 2 or 3 of these things must happen.