Question

Which of the following would be evidence that a chemical reaction has occurred? (Select all that apply.) *

Answer 1

An unexpected change in color, the odor changes , the temperature changes, precipitation is formed , formation of gas bubbles

Answer 2

Answer:

1) precipitate is formed

2) unexpected color change

3) formation of gas bubbles

4) smoke forms

5) odor change

6) substance becomes cold

Explanation:

1/3) its a new substance.

2/5) they are both changes to the original substance that cannot be reversed.

4) where theres smoke theres fire, and burning is classified as a type of chemical change.

6) it could possibly be an endothermic reaction, where it absorbs heat and the substance becomes cold.