What are the characteristics of enthalpy?

Explanation

Characteristics of enthalpy:
(i)Enthalpy is a thermodynamic property of a system. Enthalpy H is defined as sum of the internal energy (U) of a system and the product of pressure and volume of the system. That is, H=U + PV
(ii)Enthalpy is a state function which depends entirely on the state functions T,P and U .
(iii)Enthalpy is usually expressed as the change in enthalpy (`DeltaF`) for a process between initial and final states.
(iv)At constant pressure, the heat flow (q) for the process is equal to the change in enthalpy which is defined by the equation.
`DeltaH=q_P`
(v) In an endothermic reaction heat is absorbed by the system from the surroundings that is q > 0 (positive). Therefore, at constant T and P, by the equation above, if q is positive then `DeltaH` is also positive.
(vi) In an exothermic reaction heat is evolved by the system to the surroundings that is, q<0 (negative). If q is negative , then `DeltaH` will also be negative
(vii)Unit of enthalpy is KJ `mol^(-1)`