what are the 4 signs of a chemical reaction
Signs that a chemical reaction is occurring are:   1. change in color   2. change in odor   3. change in pH, as in changes from acid to base or base to acid  (lit â¦ mus paper test)   4. a gas is produced   5. energy is given off/taken in. 5 people found this useful.1. A Look at the Chemistry Definition of Reaction The word reaction is commonly used in conversation. 2  It serves a far greater purpose in the field of science. 3  You likely know the common definition for reaction already. 4  If 5  â¦. Chemical Reactions and Cream Wafers Experiments Chemical reactions come in all different ways.