The twenty most useful equations

If thermochemical data are the flesh and blood of chemical thermodynamics, then it is true to say that the bone structure is made up of a small number of defining and operating equations. While to make such a selection is necessarily arbitrary, it is felt that to present it is the best way of demonstrating the underlying structure of the subject. 

1 joule=l volt coulomb=0.009869 1 atm 1 cal=4.184 joule (exactly) (defmed)=0.04129 1 atm 1 mole=iV particles 

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