ThermodynamicsFirst law: E = q + w

The books have to balance. Energy flows downhill. The best you can do is break even.Second law: S q/T

Mess happens. You cant even break even.Free Energy, G

A theory is the more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended is its area of applicability. Therefore the deep impression which classical thermodynamics made upon meAlbert Einstein

system: the portion of the universe with which we are concernedThe surroundings: everything elseBoundary: The wall separating the system from the surroundings.Isolated system cannot exchange matter or energyClosed system can exchange energyOpen system can exchange mass and energy both

Sadi CarnotBorn: 1 June 1796 in Paris, France Died: 24 Aug 1832 in Paris, France

The First Law

E = Efinal- Einitial = q+wThe best you can do is break even. Energy flows downhill.Energy (and matter) cannot be created or destroyed.Work done ON the system BY the surroundingsHeat added TO the system BY the surroundings

E = Efinal- Einitial = q+wConstant volume of the system is assumed.HEAT: Product of random molecular motion. Worlds simplest energy. + q - Heat is absorbed from the system (enothermic).WORK: force x distance. Force may be gravitational, tensional, electrical+w - Work done ON the system.

E = Efinal- Einitial = q+wPATH INDEPENDENTWhat does that mean?

Units of energy:

1 Joule (1J) = 1kgm2/sec2

If you hold a 187 g softball 54.5 cm above the ground it has a potl energy of 1 joule

ENTHALPEINENTHALPY - To warm inH = E + PV at constant pressureH = E + P VEnthalpy is EASY TO MEASURE: It is the heat a constant pressure system absorbs or releases.

H is -

The Second Law

Die Energie der Welt ist Konstant; Die Entropie der Welt strebt einem Maximum zu. - Clausius

Einsteins desk

ENTROPY Drop a whole egg on the floor ---> ? (A B)Drop a broken egg on the floor ---> ? (B A?)Throw a new deck of cards in the air --->? (A B)Throw a random deck of cards in the air ---> ? (B A?)Spritz perfume into a room ---> ? (A B)Stand in a perfumed room with an empty bottle ---> ? (B A?)Put ice into a warm glass of lemonade ---> ? (A B)Pour warm lemonade onto some water --->? (B A?)

Second law of Thermodynamics says that spontaneous processes are characterized by the transformation of a more ordered state of system & surroundings to a more disordered state.Entropy is times arrow. Entropy is irreversible.

The Universe is a Gamble.

Klaques hand.A straight flushMy hand.I fold.Probability of being dealt Klaques Hand? 1/2.6 x 106!!!!!!!!!!Klaques hand

Probability of being dealt my hand? 1/2.6 x 106 !!!!!!!!!!But mine is junk, nada, zip, the kind of hand you get all the time but a straight flush? Thats rare

Micro and Macro States.MicrostateStraight flushI fold Macrostate# possible microstates producing the macrostate Straight Flush = 40# possible microstates producing the macrostate My Hand (I Fold) 2.6 x106The ENTROPY of a MACROSTATE IS a MEASURE of the NUMBER of MESSES (Microstates) IT CAN GET INTO

Ludwig von Boltzmann

If Entropy is against you, Ya gotta fold.Straight Flush (Klaques Hand) :S ln 40My Hand (I Fold):S ln (2.6 x106)

S = KbLn W

O (7%) Si (28%)Al (7.9%)Fe (4.5%Ca (3.5%) S = entropy of a macrostateKb is Boltzmanns Constant, 1.3807 x 10-23 J/KW is the number of microstates in the macrostateWhose hand has the higher entropy?

TAKE-HOME MESSAGE:Each MICROSTATE of a system is EQUALLY LIKELY.

The most likely MACROSTATE is the one with the MOST MICROSTATES.The Macrostate with the most microstates is the one with HIGHEST ENTROPY, and

THE ENTROPY OF THE UNIVERSE IS ALWAYS INCREASING.Ssystem + Ssurroundings = Suniverse 0

heat entropy

S q/ T at constant pressure.

Entropy, and the Air in the RoomwallBox with 10 air molecules zipping about on one side, divided by a wall

Entropy, and the Air in the Room IIPorous wallBox with 10 air molecules zipping about on one side.Punch hole in wall. What will happen?

Entropy, and the Air in the Room IIIPorous wall

AABProbability of ending up like this?

Entropy, and the Air in the Room IVPorous wallEach molecule can be in A or B side. So each has 2 possible states. With 10 molecules, the total # of possibilities is210 = 1024.AAB

Entropy, and the Air in the Room VThe total # of possibilities is210 = 1024.Of those 1024 possible arrangements, the macrostate with 9 molecules in A has 10 microstates.(10!/1!x9!)AAB

Probability = 10/1024 =.009

Entropy, and the Air in the Room VIThe total # of possibilities is still210 = 1024.The macrostate with 5 molecules in A has 252 microstates (10!/5!x5!).Probability is 252/1024 =.246AAB

Probability of ending up like this?

Probability is 252/1024 =.246A

Probability 1s 10/1024 =.009B

Which state is most likely? Which has the highest entropy?

Probability is1000!/500! X 500! 10299

And the numbers get bigger, fast! If each green dot represents 100 molecules..Probability is1000!/900!100! =6.4 x 10139

WHAT DRIVES THE UNIVERSE?

The Universe SPONTANEOUSLY ROLLS DOWNHILL (-H)and makes messes (+S) EVERYTHING ELSE TAKES WORK

Will Something Happen Spontaneously?This question is a matter of energy and entropy.Willard Gibbs answered this question in 1878, at Yale.

G = H - T S

+

G = H - T SG < 0 The process is spontaneousG > 0 The process takes energy to go.G = 0 Youre at equilibrium

G is dependent on Temperature, concentration of reactants, pH...

All those annoying little superscripts:Youll see:

G = Free energy change under standard conditions, i.e. 1.0 M, 25 C (298 K) , 1 atm.(pH is -1!).

Gf = free energy of formation from the elements:

e.g.

6C + 6H2 + 3O2 --->

Gf = free energy of formation from the elements under standard conditionse.g.

6C(s, 25 ) + 6H2(g, 1atm, 25 ) + 3O2 (g, 1atm, 25 )

--->(s, 25 ) C6H12O6

G = Free energy change under standard biological conditions, i.e. 1.0 M, 25 C (298 K) , 1 atm.pH is 7

G is concentration dependent.For any garden-variety reaction:aA + bB cC + dD

G = G + RTln( [C]c [D]d/[A]a [B]b)R = Nkb = 8.3145 J/mol K =1.9872 cal/molK = 0.08206 L atm/Kmole

At equilibrium, No NET CHANGE is occurring in the system. G = 0G = - RTln( [C]c [D]d/[A]a [B]b)= - RTlnKeq

Keq = e-G/RT

G = Gf (products) - Gf (reactants)

Problem set I is there for you at:http://academics.smcvt.edu/biochemistry/New_Folder/biochem_i_problem_set_I.htmpH Review Sessions 12-1 MTWThF

W = PV + wH = E + P VE = q-wH = q-w + P VH = qp- (PV + w) + P VH = qp- w

AT CONSTANT VOLUME: W = PV + wwork is expansion against a constant pressure + all other work.