Chem 172 Section 2 (Entropy, Equilibrium)

Front 1

Carnot Cycle

Back 1

1. reverible isothermal expansion at T2
2. reversible adiabatic expansion
3. reversible isothermal compression at T1
4. reversible adiabatic expansion

Front 2

efficiency

Back 2

-w/q

work done by sys/heat supplied

Front 3

Second Law of Thermodynamics

Back 3

-dS can only be positive or zero
-positive for spontaneous
-zero for reversible

-entropy increases when there is spontaneous change
-heat withdrawn can not be transformed completely into work with no other effect
-transferring heat from colder to warmer requires work

Front 4

Boltzmann formula for entropy

Back 4

S = kln(microstates)

states 3rd law of thermodynamics

Front 5

Third Law of Thermodynamics

Back 5

entropy of pure substance in equilib state approaches zero at absolute zero temp

Front 6

dS reversible constant V

Back 6

dS = (Cv)(ln(T2/T1))

Front 7

dS reversible constant P

Back 7

dS = (Cp)(ln(T2/T1))

Front 8

dS reversible isothermal

Back 8

dS = qrev/T
for ideal gas: dS = nRln(V2/V1)

Front 9

dS reversible adiabatic

Back 9

qrev = 0
dS = 0

Front 10

free energy

Back 10

G = H - TS
dS system + dS surroundings

negative = spontaneous
positive = not spontaneous