cEn thalpy I is a thermodynamic function that characterizes
" the energy state of the system under isobaricisothermal
• Conditions, the sun of the Internal energy of the system
' and froduct of volume and pressure. H= U + pv → the heat recened by the system at p, twoo3d cont is equal to the increment in the enthaly of the system :
Q = Hend - H start = gH
In thermodynamic calculations, only the enthalpy change that accurs when the system changes from one state to another.
The value of jH does not defend on the 
process fath, but is

Determined by the difference between the enthalpies characterizing the final and intial ststes system . 
The enthalpy of reaction is the amount of heat released or obsorbed dung carrying out chemical reactions under iroboric -ischermal conditions, characterized by change in the enthaly of the system.
- The enhaly of a system is an extensive parameter and depends t on the amount of substance, temporature, and pressure, In Merdynamies, the values of the strandard enthalpies of formation of these substances are used to estimate the energy