Maxwell Relations

Maxwell relations are links between the independent variables. We require focus on the independent variables and the directions of the arrows only.

From figure 32.1 we can write

(32.30)

Since both the arrow are in the same direction (upward), there is no change in sign. For the next Maxwell relation, we require. To rotate the Mnemonic diagram by 90⁰ (Figure 32.2)

Figure 32.2

(32.31)

For next relation, we require to rotate it by 90⁰ again (Figure 32.3)

Figure 32.3

(32.32)

Similarly for the other relation we require to rotate another 90⁰ (Figure 32.4)

Figure 32.4

And the relation is

(32.33)

Equations (32.30) - (32.33) can be re-written as

	(32.34)
	(32.35)
	(32.36)
	(32.37)

All four relations can be summarized as

or

(32.38)

Other measurable quantities, such as

Coefficient of volume expansion,

(32.39)

Compressibility

(32.40)

Specific heat at constant pressure

(32.41)

Specific heat at constant volume

(32.42)

Therfore

(32.43)