Changes to a substance that do not involve a permanent reordering of atoms are know as Question 1 options: endothermic changes. physical changes. chemical changes. irreversible changes.

Answer

Option B = physical changes

Explanation

Because in case of physical changes mass of substance and even the internal properties of the molecule remain same. Temporary changes occur that affects only physical properties of the material like size, colour and shape etc. No new substance is formed, that means the molecules and atoms are arranged in the same way in products as were in reactants.

While in case of endothermic changes new chemical bonds are formed due to breaking of existing bonds and atoms are rearranged permanently.

The answer is A. Endothermic Changes