hydrogen is a kind of element & oxygen is a kind of element ->  hydrogen and oxygen are different elements  hydrogen and oxygen are different elements & an element is a kind of substance ->  hydrogen and oxygen are different substances  hydrogen and oxygen are different substances & water is a kind of substance ->  hydrogen, oxygen, and water are different substances  electrical energy is added to water & hydrogen is produced when electrical energy is added to water ->  electrical energy causes hydrogen to form from water  oxygen is produced when electrical energy is added to water & electrical energy is added to water ->  electrical energy causes oxygen to form from water  electrical energy causes hydrogen to form from water & electrical energy causes oxygen to form from water ->  electrical energy causes hydrogen and oxygen to form from water  hydrogen, oxygen, and water are different substances & electrical energy causes hydrogen and oxygen to form from water ->  electrical energy causes different substances to form from water  electrical energy causes different substances to form from water & chemical changes cause different substances to form -> electrical energy causes chemical change to the water