title: Fundamentals of Chemical Engineering Thermodynamics (Prentice Hall International Series in the Physical and Chemical Engineering Sciences)
author:  Themis Matsoukas 
description: &nbsp;<b>Themis Matsoukas </b>has taught graduate and undergraduate thermodynamics, materials and energy balances, and various electives at Penn State&ndash;home to one of the world&rsquo;s largest undergraduate programs in engineering&ndash;since 1991. He has taught thermodynamics more than twenty times, to more than a thousand undergraduate students. His honors at Penn State include the George W. Atherton Award for Excellence in Teaching (2009); the Outstanding Teaching Award, Penn State Engineering Society (2006); and the AXE: Outstanding Teacher Award (2005). <p style="margin:0px;">&nbsp;
zlib_text: KEY CONCEPTS
  Thermochemistry is the branch of physical chemistry which deals with the thermal or heat changes
  caused by chemical reactions. It is based on first law of thermodynamics.
  ENTHALPY
  Chemical reactions are generally carried out at constant pressure (atmospheric pressure) so it has
  been found useful to define a new state function Enthalpy  (H) as :
  H = U + PV
  and hence,
  H = U + (PV)
  At constant pressure
  H = U + P V
  Combining with first law,
  H = qp
  Hence, transfer of heat at constant pressure brings about a change in the enthalpy of the system.
  Enthalpy change, rH of a reaction-Reaction enthalpy-Heat of reaction
  The enthalpy change accompanying a reaction is called the reaction enthalpy. It may also be defined as
  the amount of heat lost or gained in the chemical reaction, when all the reactants and products are
  maintained at the same temperature and pressure.
  Hess's law of constant heat summation:
  According to Hess’s law (a consequence of first law), if a set of reactan