Question

observation of chemical change reaction​

Answer 1

• change in colour.
• change in state.
• evolution of a gas.

hope this helps you ♥️ ♥️♥️

Answer 2

What is a chemical reaction?

A chemical reaction is the change of a substance into a new one that has a different chemical identity.

How can I tell if a chemical reaction is occurring?

• A chemical reaction is usually accompanied by easily observed physical effects,
• such as the emission of heat and light,
• the formation of a precipitate,
• the evolution of gas,
• or a color change.
• Absolute confirmation of a chemical change can only be validated by chemical analysis of the products