Question

With the help of an activity demonstrate how do we know that a chemical reaction has taken place

Answer 1

the only way to be certain that the chemical reaction is taking place is to test the composition of the substance after the change has taken place.colour change, precipitate formation, temperature change, light formation , gas formation are some of the activities of chemical reaction you could observe the formation of reaction.

Answer 2

when the reaction take place then to substance combine and form a new we can know it by measuring its mass