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In thermodynamics and physical chemistry, 'thermochemistry' is the study of the heat evolved or absorbed in chemical reactions. Thermochemistry, generally, is concerned with the heat exchange accompanying transformations, such as mixing, phase transitions, chemical reactions, etc., which includes calculations of such quantities as the heat capacity, heat of combustion, heat of formation, etc. The ''laws of thermochemistry'' rest on two statements:^[1]
#Lavoisier and Laplace’s law (1782): the heat exchange accompanying a transformation is equal and opposite to the heat exchange accompanying the reverse transformation.
#Hess’s law (1840): the heat exchange accompanying a transformation is the same whether the process occurs in one or several steps
Both laws preceded the first law of thermodynamics (1850); it can be shown, however, that they are a direct consequence of it.
They also investigated specific heat and latent heat.

Contents

See also

References

External links

See also

★ Important publications in thermochemistry

★ Isodesmic reaction

★ Principle of maximum work

★ Reaction Calorimeter

★ Thomsen-Berthelot principle

★ Thermodynamic databases for pure substances

References

1. A to Z of Thermodynamics, Perrot, Pierre, , , Oxford University Press, 1998, ISBN 0-19-856552-6

External links

★ Thermochemistry - Britannica (1911)

★ Thermochemistry - an overview