in three to five sentences, compare and contrast contrast chemical and physical changes.

Chemical changes involve a rearrangement of atoms leading to the formation of new substances with different properties. Physical changes, on the other hand, do not involve a change in the chemical composition of a substance, only a change in its physical properties like size, shape, or state. In a chemical change, the process is usually accompanied by energy changes and often irreversible. Physical changes, however, are typically reversible and do not involve any energy changes.