1) in a chemical reaction, if a color change is detected, if an odor change is detected, or if a precipitate is formed, then: a. a chemical reaction has definitely occurred b. only physical reactions have occurred c. a chemical reaction may have occurred d. both physical and chemical reactions have definitely occurred 2) if different products are not created during a process, then a chemical reaction has not occurred. a. true b. false

1) C. a chemical reaction may have occurred

2) True

Explanation:

C. a chemical reaction may have occurred

In a chemical reaction new products are formed from the reactant molecules and these changes are accompanied by a precipitation formation or presence of odor and color change. For example, when H₂S gas is formed it smells f rotten eggs, chlorine gas formed is detected by its greenish yellow color, and different insoluble white or colored precipitates are clearly seen with the naked eyes.

True. In a chemical change there is rearrangement of atoms such that new products are formed from reactants.