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

Chemical changes involve the breaking of bonds in molecules.

Explanation: Chemical change is a change in which there is rearrangement of atoms and thus there is formation of new substances which happens by making and breaking of bonds.

Example of chemical change:

Physical change is a change in which there is no rearrangement of atoms and thus there is no formation of new substances , thus no making or breaking of bonds is involved. It only involves changes in states.

Example of physical change:

clouds form

solid ice forms on leaves.

water droplets form on grass.

he would use the colour black