Work associated with magnetic effects

The work done on the total system when B is increased from zero to some value B is given by 

The differential quantity of work done on the system for a differential change in B is then 

We could make use of Equation (14.91) and change the variable from B to H for our simple system. However, we continue to use B because p may be dependent on the field in the general case. 

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Chemical reactions are usually associated with certain effects of energy, which can be emitted or absorbed, and are therefore categorized as exothermic or endothermic reactions. Furthermore during the chemical reaction work may also be done work in forms that are not only mechanical, but electrical, magnetic, etc. Accordingly, chemical reactions are often thermodynamic transformations and can be analyzed by thermodynamic methods. 

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