What is the difference between enthalpy and entropy?
1 Answer
Almost... everything. Letter, units... everything except that they're state functions and expressions of energy.
#color(blue)(DeltaH) = DeltaU + Delta(PV)#
#= q + w + Delta(PV)#
#= q cancel(- PDeltaV + PDeltaV) + VDeltaP + DeltaPDeltaV#
#= color(blue)(q + VDeltaP + DeltaPDeltaV)# where
#U# is internal energy,#q# is heat flow,#w# is expansion/compression work, and of course,#P# is pressure and#V# is volume.
The units for the generic enthalpy are usually in
This makes enthalpy the heat flow in a closed system, plus the amount of expansion/compression work done via a change in pressure.
#color(blue)(DeltaS >= q/T)#
#color(blue)(DeltaS = (q_"rev")/T)#
The units for the generic entropy are usually in
This makes entropy equal to the amount of reversible heat flow possible per unit temperature.
