. What do you mean by Enthalpy (H)

Best Answer

When we deal certain process in open vessels (at constant pressure). It becomes essential to introduce in place of internal energy, a new thermodynamic function called heat enthalpy. This new function is denoted by H.

H = E + PV 

Every substance has a definite value of enthalpy in a particular state. It is also a 

state function like internal energy. The change in enthalpy accompanying a process can be determined as

Hence the change in enthalpy of the system  delta H may be defined as the amount of heat absorbed at constant pressure.