Question

4 why is a temperature change an indication that a chemical change has occurred? 5 what is a chemical reaction?

Explanation:

1. In a chemical change, bonds are broken and formed. This process either releases (exothermic) or absorbs (endothermic) energy, which is manifested as a temperature change.
2. A chemical reaction is a process where one or more substances (reactants) are transformed into one or more different substances (products) through the breaking and forming of chemical bonds.

Answer:

1. A temperature change can indicate a chemical change because chemical reactions involve energy - changes related to bond - breaking and forming.
2. A chemical reaction is the transformation of reactants into products through bond - breaking and forming.