What is Enthalpy?

Enthalpy: At a particular condition, the total stored energy of the system is called enthalpy of that system.

Enthalpy H = U + PV

U = internal energy

P = pressure, V = volume

The significance of ∆H: If the reaction is exothermic, ∆H is negative (-) and if the reaction is endothermic ∆H is positive. So we can determine exothermic and endothermic reaction by ∆H.