What happens during a chemical change?

Mass is lost

composition changes

composition stays the same

composition changes

Explanation:

The main difference between physical and chemical changes is the following:

- in a physical change, no new substances are formed, while the atoms/molecules of the original substances can be re-arranged. Examples of physical changes are the change of state (for instance, from solid to liquid) : no new substance are formed, but the bonds between molecules are broken and the molecules change position/arrangement.

- in a chemical change, new substances are formed: an example of this change are chemical reaction, such as the burning of a substance, in which new substances are formed. For this reason, the composition changes during a chemical change.