How does the law of conservation of energy and the law of conservation of mass apply to changes of state?

The Law of conservation of Energy applies to mass as mass is a form of energy, E=mc2.

The Law of Conservation of Energy states: Energy cannot be created or destroyed but merely change from one form to another.Einstein showed that matter is a form of energy. When a nuclear decay occurs...

Conservation of energy says that Mass-Energy can not be created nor destroyed.

when one form of energy is transformed to another, no energy is destroyed in the process.

Matter cannot be created or destroyed in an isolated system.