Physical Chemistry Material Equilibrium Calculation of changes in state functions △S= Q2 cpdt avdp (460) . AS for the process(Pl, TD>(P2, T2)is independent of the path used. A convenient path(Fig. 4.5 )is suggested △S Pdr const. P=P,(4.61 △S b avdP const. T-T2(4.62)P AS for the process(P, T1>(P2, T2)is T △S=△Sa+ASb Fig 4.5Calculation of changes in state functions    = − = − 2 1 2 1 2 1 dT VdP T C S S S P  (4.60)   = 2 1 T T P a dT T C S const. P=P1 (4.61)   = − 2 1 P P Sb VdP const. T=T2 (4.62) S = Sa + Sb S for the process (P1 , T1 )→ (P2 , T2 ) is P P1 P2 T1 T2 T 1 2 (a) (b) Fig. 4.5 S for the process (P1 , T1 )→ (P2 , T2 ) is independent of the path used. A convenient path (Fig. 4.5) is suggested. Physical Chemistry Material Equilibrium