1. Chapter 10 Spontaneity, Entropy, and Free Energy

2. Concept for second law of thermodynamic 熱機原理 壓縮機原理 亂度

3. Isothermal expansion device

4. One-Step Expansion (No Work) Mass M 1 is removed from the pan, the gas will expand, moving the piston to the right end of the cylinder. P 1 →1/4P 1, V 1 →4V 1, No work is done. W 0 =0 Free expansion

5. One-Step Expansion M 1 is replaced by M 1 /4.

6. Two-Step Expansion P 1 →1/2P 1, V 1 →2V 1 1/2P 1 →1/4P 1, 2V 1 →4V 1

7. PV diagram two-step expansion

8. The PV diagram six-step expansion

9. Infinite-Step Expansion (dV: △ V→0 )

10. Reversible expansion

11. Reversible Process Reversible process: the system is always infinitesimally close to equilibrium, and an infinitesimal change in conditions can reverse the process to restore both system and surroundings to their initial states.

12. Heat Engines A heat engine converts some of the random molecular energy of heat flow into macroscopic mechanical energy. q H : the working substance from a hot body -w: the performance of work by the working substance on the surroundings -q C : the emission of heat by the working substance to a cold body

13. The Second Law of Thermodynamics Kelvin-Planck statement for heat engine It is impossible to extract an amount of heat q H from a hot reservoir and use it all to do work W. Some amount of heat q C must be exhausted to a cold reservoir. This is sometimes called the "first form" of the second law, and is referred to as the Kelvin-Planck statement of the second law.

15. Heat Efficiency

16. The Second Law of Thermodynamics Clausius statement for refrigerator It is not possible for heat to flow from a colder body to a warmer body without any work having been done to accomplish this flow. Energy will not flow spontaneously from a low temperature object to a higher temperature object. The statements about refrigerators apply to air conditioners and heat pumps which embody the same principles.

18. Carnot’s Principle No heat engine can be more efficient than a reversible heat engine when both engines work between the same pair of temperature  H and  C. Isothermal Process: the temperature of the system and the surroundings remain constant at all times. (q=-w) Adiabatic: a process in which no energy as heat flows into or out of the system. (∆U=w)

19. Carnot cycle four stage reversible sequence consisting of 1. isothermal expansion at high temperature T 2 2. adiabatic expansion 3. isothermal compression at low temperature T 1 4. adiabatic compression

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23. 0 0

25. Adiabatic Process

27. Isothermal process ∆U=0, q=-w

28. Adiabatic process No heat transfer (q=0), ∆U=w

29. Adiabatic Process Process in which no heat transfer takes place

30. Application of Carnot Cycle P (atm)V (L) 310 1.520 125.5 212.75 Calculate Q, U, W First law: △ U = Q H – Q L + W  W = Q L - Q H

31. Spontaneous Process and Entropy Spontaneous Process: A process occurs without outside intervention. Entropy: In qualitative terms, entropy can be viewed as a measure of randomness or disorder of the atoms or molecules in a substance.

33. Definition of Entropy S=k B lnΩ k B : Boltzmann’s constant Ω : the number of microstates corresponding to a given state

34. For one particle S 1 =k B lnΩ 1 S 2 =k B lnΩ 2 ∆S=S 2 -S 1 = k B lnΩ 2 -k B lnΩ 1 =k B ln(Ω 2 /Ω 1 ) ∆S= k B ln(2Ω 1 /Ω 1 )=k B ln2

35. 醫學系 M104 林琬錡提供

36. 巨觀來看 微觀來看 Ω 4 顆粒子都有 2 種選擇，微觀態數： 2 4 =16 醫學系 M104 林琬錡提供

37. Definition of entropy in term of probability

38. Entropy for Isothermal Process

39. Entropy and Physical Changes Temperature Dependence

40. Entropy and Physical Changes Change of State Change of state from solid to liquid q rev =ΔH fusion T=melting point in K Change of state from liquid to gas q rev =ΔH vaporization T=boiling point in K

41. The Second Law of thermodynamics The Third Statement In any spontaneous process, there is always an increase in the entropy of the universe. dq/T is the differential of a state function S that has the property ∆S univ ≥ 0 for any process

42. Entropy and Second Law of Thermodynamics ΔS univ = ΔS sys +ΔS surr

43. Gibbs Free Energy △ S univ >0, so △ G<0

46. Free Energy and Chemical Reactions

47. Third Law of Thermodynamics The entropy of a perfect crystal at 0 K is zero. It is impossible to reach a temperature of absolute zero It is impossible to have a (Carnot) efficiency equal to 100% (this would imply T c = 0).

48. ( a) T=0 K, S=0 (b) T>0 K, S>0

49. The Dependence of Free Energy on Pressure

50. Free Energy and Equilibrium

51. The Temperature Dependence of K

53. Free Energy and Work