In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time.
spanish:
En física y química, la ley de conservación de la energía establece que la energía total de un sistema aislado permanece constante; se dice que se conserva con el tiempo.
The half-cells separate the oxidation half-reaction from the reduction half-reaction and make it possible for current to flow through an external wire.
