Question

how we understand that chemical changing happened​

Answer 1

Explanation:

HEY MATE ..

A chemical change happens when one chemical substance is transformed into one or more different substances, such as when iron becomes rust.Chemical changes occur through the process of chemical reactions, and the resulting substances have different properties because their atoms and molecules are arranged differently.A chemical change is different from a physical change, which doesn’t rearrange atoms or molecules and produce a completely new substance. Ice melting into water is an example of a physical change.

Answer 2

Answer:

A chemical reaction takes place when one or more substances are changed into a new substance. This means that the chemical composition of a substance changes. It is important to remember that matter is neither created nor destroyed in a chemical reaction. Instead, a substance is simply rearranged to form another one.

example

Change of odor. Change of color (for example, silver to reddish-brown when iron rusts). Change in temperature or energy, such as the production (exothermic) or loss (endothermic) of heat. Change of composition - paper turning to ash when burned