Question

What characterizes a chemical reaction?

Answer 1

`"A colour change......."`

Explanation:

`"...or the formation of new substances......"`

Chemical change is characterized by the formation of new substances and the making and breaking of strong chemical bonds.

I have written the [same thing here.](https://socratic.org/questions/what-is-an-indicator-that-a-chemical-reaction-has-taken-place?source=search)