E = sum kinetic energy/motion of molecule, and potential energy represented by chemical bond bet atom

∆E = q + w

∆E = Change internal energy

q = heat transfer

w = work done by/on system

Thermodynamics Study of work, heat and energy on a system

∆E universe = ∆E sys + ∆E surrounding = 0

1st Law Thermodynamics

Entropy - Measure of disorder↓

∆S uni = ∆S sys + ∆S surr > 0 (irreversible rxn)↓

All spontaneous rxn produce increase in entropy of universe

2nd Law Thermodynamics

∆S uni = ∆S sys + ∆S surr

Isolated system - Entropy change of universe always increase

Click here thermodynamics entropyEntropy

Measure molecular disorder/randomness↓

More disorder - More dispersion of matter/energy↓

More random - Rxn toward right- Entropy Increases ↑

Direction to right- Spontaneous to right →

2nd Law Thermodynamics

Embrace the chaos

Over time - Entropy increase ↑

Direction to left ← Never happen !

Click here thermodynamics

Energy cannot be created or destroyed

> 0

∆S = Entropy change

Entropy

Dispersal/DistributionMatter Energy

Matter more disperse ↑

Entropy increases ↑

solid liquid gas

spontaneous - entropy ↑

Over time - Entropy increase ↑

Phase change - sol → liq → gas↓

Entropy increase ↑

Every energy transfer - increase entropy universeEntropy universe can only go up - never go down Entropy increase - many ways energy spread out

Dispersion energy as heat - increase entropy

Stoichiometry- more gas/liq in product ↓

Entropy increase ↑

TQS

Heat added ↑Phase change Stoichiometry

Embrace the chaos

N2O4 (g) → 2NO2(g)

1 2

2H2O(l) → 2H2 (g) + O2 (g)

1 23

3

More gas in product - Entropy ↑

Heat added ↑

Entropy

Measure molecular disorder/randomness↓

More disorder - More dispersion of matter/energy↓

More randon - Rxn towards right- Entropy Increases ↑

Liq more disorder than solidGas more disorder than liq

kinetic energy distributed over wide range

Q = heat transfer

T = Temp/K

Distribution matter in space Distribution energy bet particles

Direction to left ← Never happen !Direction to right- Spontaneous to right →

TQS

StatisticalEntropy

Entropy

Measure molecular disorder/randomness↓

More disorder - More dispersion of matter/energy↓

More random - Entropy Increases ↑

1st Law Thermodynamics - Doesn't help explain direction of rxn∆S uni > 0 (+ve) → More disorder - spontaneous∆S uni < 0 (-ve) → More order - non spontaneous

Change sol → liq → gas - Higher entropyGreater number particles in product - Higher entropy

More complex molecule - More atoms bonded - Higher entropyHigher temp - Vibrate faster - More random - Higher entropy

Why gas mixes and not unmix? Why heat flow from hot to cold?

Entropy

Notes on Entropy

1st Law Thermodynamics 2nd Law Thermodynamics

Energy cannot be created or destroyedTransfer from one form to another

∆E universe = ∆E sys + ∆E surrounding = 0

Isolated system ↓

∆S uni always increase

∆E = q + w

Method to calculate entropy

Number microstates

Thermodynamic Entropy

Heat + Temp involved

Gas mixesSolution diffuse Heat flow hot →cold

X X X

∆E = internal energy

q = heat transfer

w = work done ∆S = Entropy universe

∆S = Entropy system

∆S = Entropy surrounding

∆S uni = ∆S sys + ∆S surr

Law Thermodynamics

1 2

∆S = Entropy change

Q = heat transferWkS ln

T = Temp/K∆S = Entropy change

k = boltzmann constant

W = Microstate

Click here statistical entropy Click here thermodynamics entropy

Why solution diffuse and not undiffuse?

Unit - J mol -1 K-1

1st Law Thermodynamics - Doesn't help explain direction of rxn∆S uni > 0 (+ve) → More disorder - spontaneous∆S uni < 0 (-ve) → More order - non spontaneousChange from sol → liq → gas - Higher entropy

Greater number particles in product - Higher entropyMore complex molecule - More atoms bonded - Higher entropyHigher temp - Vibrate faster - More random - Higher entropy

Measure molecular disorder/randomness↓

More disorder - More dispersion of matter/energy↓

More random - Entropy Increases ↑

Isolated system ↓

∆S uni always increase

Entropy

Why gas mixes and not unmix? Why heat flow from hot to cold?

Notes on Entropy

1st Law Thermodynamics 2nd Law Thermodynamics

Energy cannot be created or destroyedTransfer from one form to another

∆E universe = ∆E sys + ∆E surrounding = 0

∆E = q + w

Gas mixesSolution diffuse Heat flow hot →cold

X X X

∆E = internal energy

q = heat transfer

w = work done ∆S = Entropy universe

∆S = Entropy system

∆S = Entropy surrounding

∆S uni = ∆S sys + ∆S surr

Law Thermodynamics

3rd Law Thermodynamics

Unit - J mol -1 K-1

Standard Molar Entropy, S0

Entropy perfectly crystal at 0K = 0Std molar entropy, S0

↓S0 when substance heated from 0K to 298K

Std state - 1 atm / 1M sol

Temp = 298K

Std Molar Entropy/S0 S0 at 298 /JK-1 mol-1

H2O (s) + 48

H2 (g) + 130

Na (s) + 52

H2O (l) + 69

CH3OH (l) + 127

H2O (g) + 188

CO2 (g) + 218

Fe (s) + 27 Solid - Order↓

Entropy Lowest

Liq - Less order↓

Entropy Higher

Gas - Disorder↓

Entropy Highest

Entropy highest

Why solution diffuse and not undiffuse?

Entropy

Why gas mix and not unmix? Why solution diffuse and not undiffuse? Why heat flow from hot to cold?

Gas mixesSolution diffuse Heat flow hot →cold

X X X

Unit - J mol -1 K-1

Standard Molar Entropy, S0

Entropy perfectly crystal at 0K = 0↓

S0 when substance heated from 0K to 298K

Std state - 1 atm / 1M sol

Temp = 298K

Std Molar Entropy/S0 S0 at 298 /JK-1 mol-1

H2O (s) + 48

H2 (g) + 130

Na (s) + 52

H2O (l) + 69

CH3OH (l) + 127

H2O (g) + 188

CO2 (g) + 218

Fe (s) + 27 Solid - Order↓

Entropy Lowest

Liq - Less order↓

Entropy Higher

Gas - Disorder↓

Entropy Highest

Entropy highest

Entropy

Standard Molar Entropy, S0

Depends on

Temp increase ↑ - Entropy increase ↑

Physical/phase state

Dissolving solid Molecular mass

Click here thermodynamics entropy Ba(OH)2

Temp

Temp/K 273 295 298

S0 for H2 + 31 + 32 + 33.2

Sol → Liq → Gas - Entropy increase ↑

State solid liquid gas

S0 for H2O + 48 + 69 + 188

entropy increase ↑ entropy increase ↑

Depends on

Substance NaCI NH4NO3

S0 for solid + 72 + 151

S0 for aq + 115 + 260

More motion - entropy increase ↑ Higher mass - entropy increase ↑

Substance HF HCI HBr

S0 + 173 + 186 + 198

Molar mass 20 36 81

S0 = 0 at 0KAll sub > 0K, have +ve S0

Entropy perfectly crystal at 0K = 0↓

S0 when substance heated from 0K to 298K

Entropy

Why gas mix and not unmix? Why solution diffuse and not undiffuse? Why heat flow from hot to cold?

Gas mixesSolution diffuse Heat flow hot →cold

X X X

Unit - J mol -1 K-1

Standard Molar Entropy, S0

Std state - 1 atm / 1M sol

Temp = 298K

Std Molar Entropy/S0 S0 at 298 /JK-1 mol-1

H2O (s) + 48

Na (s) + 52

H2O (l) + 69

CH3OH (l) + 127

H2O (g) + 188

CO2 (g) + 218

Solid - Order↓

Entropy Lowest

Liq - Less order↓

Entropy Higher

Gas - Disorder↓

Entropy Highest

Entropy highest

Entropy

Standard Molar Entropy, S0

Depends on

Temp increase ↑ - Entropy increase ↑

Physical/phase state

Dissolving solid Molecular mass

Temp

Temp/K 273 295 298

S0 for H2 + 31 + 32 + 33.2

Sol → Liq → Gas - Entropy increase ↑

State solid liquid gas

S0 for H2O + 48 + 69 + 188

entropy increase ↑ entropy increase ↑

Depends on

More motion - entropy increase ↑

Click here entropy notes

Click here entropy, enthalpy free energy data

Click here entropy CRC data booklet

Higher mass - entropy increase ↑

S0 = 0 at 0KAll sub > 0K, have +ve S0

Substance NaCI NH4NO3

S0 for solid + 72 + 151

S0 for aq + 115 + 260

Substance HF HCI HBr

S0 + 173 + 186 + 198

Molar mass 20 36 81

N2O4 (g) → 2NO2(g)

Reactant Product

Entropy

Ice (s) Water (l)

Entropy

Why gas mixes and not unmix? Why conc solution diffuse and not undiffuse? Why heat flow from hot to cold?

Method to calculate entropy

Gas mixesSolution diffuse Heat flow hot →cold

X X X

Qualitatively

Solid → Liquid NaCI(s) → Na+(aq) + CI -(aq)

N2O4 (g) → 2NO2(g)

Reactant ProductS θ Less More

More microstates (More dispersion/random/freedom of motion)

Solid → liq → gas

Higher ↑ entropy

Greater number particles in product More liq/gas in product

Dispersion Energy Microstate

More dispersion of energy(Electronic, translational, rotational, vibrational, thermal)

Higher entropy ∆S > 0 (+ve) - Spontaneous

∆Srxnθ = ∑Sf

θ(pro) - ∑Sf

θ(react)

∆Srxnθ = More - Less

= +ve > 0

S θ Less More

∆Srxnθ = ∑Sf

θ(pro) - ∑Sf

θ(react)

∆Srxnθ = More - Less

= +ve > 0

∆Srxnθ = ∑Sf

θ(pro) - ∑Sf

θ(react)

∆Srxnθ = More - Less

= +ve > 0

NaCI(s) → Na+(aq) + CI -(aq)

S θ Less MoreReactant Product

QualitativelyUnit - J mol -1 K-1

Reactant Product

Entropy

Liq N2(l) Gas N2 (g)

Entropy

Why gas mixes and not unmix? Why conc solution diffuse and not undiffuse? Why heat flow from hot to cold?

Method to calculate entropy

Gas mixesSolution diffuse Heat flow hot →cold

X X X

Qualitatively

Liquid → Gas

Reactant ProductS θ Less More

More microstates (More dispersion/random/freedom of motion)

Solid → liq → gas

Higher entropy

Greater number particles in product More liq/gas in product

Dispersion Energy Microstate

More dispersion of energy(Electronic, translational, rotational, vibrational, thermal)

Higher entropy ∆S > 0 (+ve) - Spontaneous

∆Srxnθ = ∑Sf

θ(pro) - ∑Sf

θ(react)

∆Srxnθ = More - Less

= +ve > 0

S θ Less More

∆Srxnθ = ∑Sf

θ(pro) - ∑Sf

θ(react)

∆Srxnθ = More - Less

= +ve > 0

∆Srxnθ = ∑Sf

θ(pro) - ∑Sf

θ(react)

∆Srxnθ = More - Less

= +ve > 0

NH4NO3(s) → NH4+

(aq) + NO3 -(aq)

S θ Less MoreReactant Product

Qualitatively

NH4NO3 (s) → NH4 +(aq) + NO3 - (aq) Ba(OH)2 .8H2O(s) + 2NH4NO3 (s) →

Ba2+(aq) + 2NO3

-(aq) + 2NH3 (g) + 10H2O(aq)

Ba(OH)2 .8H2O(s) + 2NH4NO3 (s) → Ba2+(aq) + 2NO3

- (aq) + 2NH3 (g) +10H2O(aq)

Unit - J mol -1 K-1

+

Find entropy change when value open ?

Initial Microstate, Wi = 1 Final Microstate, Wf = 2

StatisticalEntropy

Entropy

Why gas mixes and not unmix? Why conc solution diffuse and not undiffuse? Why heat flow from hot to cold?

Entropy

Method to calculate entropy

Number microstates Thermodynamic Entropy

Heat + Temp involved

Gas mixesSolution diffuse Heat flow hot →cold

X X X

1 2

∆S = Entropy change

Q = heat transfer

WkS lnT = Temp/K

S = Entropy

k = boltzmann constant

W = Microstate

Quatitatively

TQS

k = R/NA = 1.38 x 10-23 J K-1 Click here statistical entropy

1241056.9 JKS

or

∆S = S f - S i = klnWf - klnWi

i

f

WW

kS ln 2ln12ln kkS

S initial S final

Find entropy change when 334kJ heat added to melt 1kg ice to water at 273K?

Click here thermodynamic entropy

11227273334000 JKS

TQS 1 kg

Q = 334kJ

Quatitatively

Q = heat transfer

TQS

Find entropy change when value open ?

Initial Microstate, Wi = 1 Final Microstate, Wf = 4

Statistical Entropy

Entropy

Why gas mixes and not unmix? Why conc solution diffuse and not undiffuse? Why heat flow from hot to cold?

Entropy

Method to calculate entropy

Thermodynamic Entropy

Gas mixesSolution diffuse Heat flow hot →cold

X X X

1 2

∆S = Entropy change

WkS lnT = Temp/K

S = Entropy k = boltzmann constant

W = Microstate

Quatitatively

1231091.1 JKS

∆S = S f - S i = klnWf - klnWi

i

f

WW

kS ln 4ln14ln kkS

S initial S final

A has 250g water at 100C and B has 250g ice at OC.Find ∆S when value open, temp of both A/B at 50C? Heat transfer A → B. Heat loss by A. Heat gain by B

125175150 JKSSS BAsys

1150348

50184.4250

JKTmc

TQSA

A100C

Quatitatively

B0C

1175298

50184.4250

JKTmc

TQSB

Assume ∆S negligible (over small range Temp)

A50C

B50C

Ave temp takenA - 100 → 50C Ave - 75C (348K)

Ave temp takenB - 0 → 50C Ave 25C (298K)

Click here statistical thermodynamicsClick here thermodynamics entropy

Entropy decrease ↓

Entropy

Why gas mixes and not unmix? Why conc solution diffuse and not undiffuse? Why heat flow from hot to cold?

Predict entropy change - qualitatively

Gas mixesSolution diffuse Heat flow hot →cold

X X X

NH4NO3 (s) → NH4 +(aq) + NO3 - (aq)

C3H8(g) + 5O2 (g) → 3CO2(g) + 4H2O(g) 2H2(g) + O2 (g) → 2H2O(l)

2Cu(s) + O2 (g) → 2CuO(s)

Br2(l) → Br2(g)

Ag+(aq) + Br-

(aq) → AgBr(s) H2(g) + CI2 (g) → 2HCI(g)

Cu2+(aq) + Zn(s) → Cu(s) + Zn2+

(aq) CaCO3 (s) → CaO(s) + CO2 (g)

1

Entropy decrease ↓

Entropy decrease ↓ Entropy increase ↑

Entropy increase ↑Entropy increase ↑

Entropy increase ↑

Little change

Little change

2 3

4

Reactant Product

aq - more disorder solid - more order S higher ↑ S - Lower ↓

Reactant Product

g - more disorder solid - more order S higher ↑ S - Lower ↓

Reactant Product

Both sides equal number mol gas

Reactant Productg - more disorder liq - more order S higher ↑ S - Lower ↓

Reactant Product

liq- more order g - more disorder S Lower ↓ S - Higher↑

Reactant Product

less g- more order more g - more disorder S Lower ↓ S - Higher↑

Reactant Product

Both sides equal number mol solid

Reactant Product

solid- more order aq - more disorder S Lower ↓ S - Higher↑

Reactant Product

solid- more order g - more disorder S Lower ↓ S - Higher↑

5 6

7 8 9