Entropy

In terms of the single-partition function,

(5.231)

In terms of Z_tot, since

(5.232)

Helmholtz Function

(5.233)

Pressure

(5.234)

Gibbs Function

(5.235)

Enthalpy

(5.236)

Work and Heat
Let us consider a single particle in a rectangular box with dimension a, b and c.
Let F = force exerted by the particle in x direction
da = displacement of right wall
work done by the particle = Fi da = decrease in energy dε_i

or

or

Let = mean force exerted

(5,237)

Again,

(5.238) (5.239) (5.240)

which is valid for a reversible process.