Answer;
-Changing the color of a metal; For example Painting a metal car does not changing the composition of the metallic substance.
Explanation;
-The major difference of physical and chemical reaction is the fact that; In a chemical reaction, there is a change in the composition of the substances in question while in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.
-Changing the color of a substance is not necessarily an indicator of a chemical change. For example, changing the color of a metal does not change its physical properties. However, in a chemical reaction, a color change is usually an indicator that a reaction is occurring.