Answer:
Bonds are broken and new bonds are formed during chemical reactions only.
Explanation:
- A physical change in a substance doesn't change what the substance is.
- In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.
- Physical changes can be reversed, chemical changes cannot be reversed with the substance changed back without extraordinary means, if at all. For example, a cup of water can be frozen when cooled and then can be returned to a liquid form when heated.
So, the right choice is:
Bonds are broken and new bonds are formed during chemical reactions only.