Question

Which of these is NOT a sign that a chemical reaction has happened?

A) release of heat or light
B) a new precipitate (solid) forming
C) change in state (ex. solid to liquid)
D) bubbles or gas forming

Answer 1

A

Step-by-step explanation:

B, C, and D all have something that causes the reaction But A Did itself

Answer 2

Answer: C, because a change in state is reversable without a reaction due to the fact that it is still the same substance, with no additional substances being made or without converting the current substance into another.