In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. The distinction between physical and chemical change is not clear cut.
Following are the chemical and structural formulae of said complex compound,
It takes the Earth 24 hours to rotate on its axis and this rotation is what causes there to be days and nights.
Heat the water up a little