Question

How do you recognize substances that have gone through physical or chemical changes?

Answer 1

Normally  you can't.   You cannot tell if water has been frozen and then thawed.

Answer 2

Answer:

you normally cant tell if something went through chemical change, like sugar and coffee, after the sugar melts into the coffee you cant get it back or tell if there is sugar in it by looking at it.

Explanation:

hope this helps! :)