Question

how are chemical and physical changes different on a molecular level?
chemical changes involve the breaking of bonds in molecules.
chemical changes do not alter bonding between atoms.
physical changes do not involve molecules.
physical changes cause new molecules to form.

Explanation:

Chemical changes involve the breaking and forming of chemical bonds between atoms to create new substances at the molecular level. Physical changes do not involve a change in the chemical composition of substances and do not break or form new molecules.

Answer:

Chemical changes involve the breaking of chemical bonds.