Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at...

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Chapter 10: Spontaneity, Entropy, and Free Energy Chapter 10: Phenomena Exp. Reaction Direction Reaction Runs ΔE˚ ΔH˚ ΔG˚ ΔS˚ 1 4Fe(s) + 3O 2 (g) 2Fe 2 O 3 (s) Forward -1,635 -1,642 -1,484 -549 2 NH 4 NO 3 (s) NH 4 + (aq) + NO 3 - (aq) Forward 26 26 -6 108 3 4AlCl 3 (s) + 9O 2 (g) 2Al 2 O 3 (s) + 12ClO(g) Reverse 679 686 520 545 4 4NH 3 (g) + 5O 2 (g) 4NO(g) + 6H 2 O(g) Forward -911 -908 -958 181 5 H 2 O(l) H 2 O(s) Reverse -6 -6 0.5 -22 Phenomena: Below is data from several different chemical reactions. All reaction were started by putting some of every substance in the chemical reaction into an expandable/contractable container at 25˚C. If reactants/products were in a gas state, 1 atm of the gas was added to the container. If reactants/products were in an aqueous state, 100 mL of water was added to the container and then the concentrations were adjusted to 1M using solids. If the reactants/products were in a liquid or solid state, 10 g of the substance was added. Therefore, for the reaction: 4Fe(s) + 3O 2 (g) 2Fe 2 O 3 (s) 10 g of Fe, 10 g of Fe 2 O 3 , and 1 atm of O 2 would be put into the reaction container. Looking at the thermodynamic data that was gathered see what patterns you can identify. (You do not need to know what ΔG˚ or ΔS˚ are to identify the patterns.)

Transcript of Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at...

Page 1: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Chapter 10: Phenomena

Exp. ReactionDirection Reaction

Runs

ΔE˚ ΔH˚ ΔG˚ ΔS˚

1 4Fe(s) + 3O2(g) 2Fe2O3(s) Forward -1,635 𝑘𝐽

𝑚𝑜𝑙-1,642 𝑘𝐽

𝑚𝑜𝑙-1,484 𝑘𝐽

𝑚𝑜𝑙-549 𝐽

𝑚𝑜𝑙∙𝐾

2NH4NO3(s)

NH4+(aq) + NO3

-(aq)Forward 26 𝑘𝐽

𝑚𝑜𝑙26 𝑘𝐽

𝑚𝑜𝑙-6 𝑘𝐽

𝑚𝑜𝑙108 𝐽

𝑚𝑜𝑙∙𝐾

34AlCl3(s) + 9O2(g) 2Al2O3(s) + 12ClO(g)

Reverse 679 𝑘𝐽

𝑚𝑜𝑙686 𝑘𝐽

𝑚𝑜𝑙520 𝑘𝐽

𝑚𝑜𝑙545 𝐽

𝑚𝑜𝑙∙𝐾

44NH3(g) + 5O2(g) 4NO(g) + 6H2O(g)

Forward -911 𝑘𝐽

𝑚𝑜𝑙-908 𝑘𝐽

𝑚𝑜𝑙-958 𝑘𝐽

𝑚𝑜𝑙181 𝐽

𝑚𝑜𝑙∙𝐾

5 H2O(l) H2O(s) Reverse -6 𝑘𝐽

𝑚𝑜𝑙-6 𝑘𝐽

𝑚𝑜𝑙0.5 𝑘𝐽

𝑚𝑜𝑙-22 𝐽

𝑚𝑜𝑙∙𝐾

Phenomena: Below is data from several different chemical reactions. All reaction

were started by putting some of every substance in the chemical reaction into an expandable/contractable container at 25˚C. If reactants/products were in a gas

state, 1 atm of the gas was added to the container. If reactants/products were in

an aqueous state, 100 mL of water was added to the container and then the

concentrations were adjusted to 1M using solids. If the reactants/products were in

a liquid or solid state, 10 g of the substance was added. Therefore, for the

reaction: 4Fe(s) + 3O2(g) 2Fe2O3(s) 10 g of Fe, 10 g of Fe2O3, and 1 atm of O2

would be put into the reaction container. Looking at the thermodynamic data

that was gathered see what patterns you can identify. (You do not need to know what ΔG˚ or ΔS˚ are to identify the patterns.)

Page 2: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10

Spontaneity,

Entropy, &

Free Energy

o Entropy

o ΔS of Physical Reactions

o Isothermal Processes

o 2nd Law of Thermo

o Free Energy

o Hess’s Law/ 3rd Law of

Thermo

o Equilibrium

2

Big Idea: The change in free

energy of a reaction

indicates whether a

reaction is

spontaneous. In any

spontaneous process

there is always an increase in the entropy of the universe.

Page 3: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Entropy

Entropy (S): Entropy is

a measure of how

energy and matter

can be distributed in a

chemical system. 3

# of molecules

of left side

# of ways of

arranging

(microstates)

4

3

2

1

0

Page 4: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Entropy

In General:

Entropy increases from solid to liquid to gas corresponding

to an increase in positional probability.

Entropy increases when you dissolve a solid in liquid

corresponding to an increase in positional probability.

The larger the volume the larger the positional probability and the greater the entropy (n constant).

The larger the pressure the smaller the positional

probability and the lower the entropy (n constant).

The larger the molecule the larger the number of relative

positions of the atoms resulting in a greater positional

probability and a greater entropy.

The higher the temperature the greater the range of energies, therefore the larger the entropy.

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Page 5: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Student Question

Entropy

Predict which of the following reactions has a

negative entropy change.

I. CH4(g) + 2O2(g) CO2(g) + 2H2O(l)

II. NH3(g) + HCl(g) NH4Cl(s)

III. 2KClO4(s) 2KClO3(s) + O2(g)

a) II and III

b) III

c) II

d) I

e) I and II

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Page 6: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Entropy

Phase Change: The condition (for a given

pressure, and temperature) at which two

different phases are in dynamic

equilibrium.

Melting/Freezing Liquid/Solid

Evaporation/Condensation Liquid/Gas

Sublimation/Deposition Solid/Gas

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Page 7: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

ΔS of Physical Reactions

Calculating ΔS for physical reaction X(s, Ti) X(g, Tf)

Step 1: Calculate ΔS

to bring to melting point

Step 2: Calculate ΔS

involved in fusion

Step 3: Calculate ΔS

to bring to boiling point

Step 4: Calculate ΔS

involved in vaporization

Step 5: Calculate ΔS

to bring to final temperature

7

fusn HS

T

vapn HS

T

∆𝑆 = 𝑚𝐶𝑠𝑜𝑙𝑖𝑑𝑙𝑛𝑇𝑀𝑇𝑖

∆𝑆 = 𝑚𝐶𝑙𝑖𝑞𝑢𝑖𝑑𝑙𝑛𝑇𝐵𝑇𝑀

∆𝑆 = 𝑛𝐶𝑃𝑔𝑎𝑠𝑙𝑛𝑇𝑓

𝑇𝐵

Page 8: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Student Question

ΔS of Physical Reactions

What is ΔS for 88.0 g of CO2 undergoing the

following reaction at constant pressure? CO2(s, 150. K) CO2(g, 195. K)

Helpful Information: 𝑇𝑠𝑢𝑏 = 195𝐾, ∆𝐻𝑠𝑢𝑏 = 25.2 𝑘𝐽

𝑚𝑜𝑙, 𝐶𝐶𝑂2(𝑠) =

1.07 𝐽

𝑔∙𝐾

a) 24.9𝐽

𝐾

b) 154𝐽

𝐾

c) 233𝐽

𝐾

d) 283𝐽

𝐾

e) None of the above

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Page 9: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Isothermal Processes

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Page 10: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

2 Step Isothermal Expansion 6 Step Isothermal Expansion

Note: In order for a reversible process to

occur the system must be at equilibrium

during the entire process.

Pre

ssu

re

1P

21P

41P

∞ Step Isothermal Expansion

1V 12V 14V

Pre

ssu

re

1P

21P

41P

1V12V 14V

Pre

ssu

re

1P

21P

41P

Volume1V

12V 14V

Isothermal Processes

Reversible Process: A

process that can be

reversed by an infinitesimal

change in a variable.

10

Volume Volume

Page 11: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Student Question

Isothermal Processes

Calculate the ΔS associated with a process in

which 5.00 mol of gas expands reversibly at

constant temperature T = 25°C from a pressure

of 10.0 atm to 1.00 atm.

a) 28,500𝐽

𝐾

b) 95.7𝐽

𝐾

c) -95.7𝐽

𝐾

d) -28,500𝐽

𝐾

e) None of the above

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Page 12: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

2nd Law of Thermo

2nd Law of Thermodynamics: A

spontaneous change is accompanied by

an increase in the total entropy of the

system and its surroundings.

∆𝑆𝑢𝑛𝑖 = ∆𝑆𝑠𝑦𝑠 + ∆𝑆𝑠𝑢𝑟

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Note: The second law of thermodynamics applies to ΔSuni and not ΔSsys. So far we

have only discussed ΔSsys.

Page 13: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Free Energy

Can we relate spontaneity to a change in

the system instead of the universe assuming

we are at constant temperature and

pressure?

∆𝐺𝑠𝑦𝑠= ∆𝐻𝑠𝑦𝑠 − 𝑇∆𝑆𝑠𝑦𝑠

Divide Through by T

∆𝐺𝑠𝑦𝑠

𝑇=

∆𝐻𝑠𝑦𝑠

𝑇−

𝑇∆𝑆𝑠𝑦𝑠

𝑇

∆𝐺𝑠𝑦𝑠

𝑇= −∆𝑆𝑠𝑢𝑟 − ∆𝑆𝑠𝑦𝑠

−∆𝐺𝑠𝑦𝑠

𝑇= ∆𝑆𝑢𝑛𝑖𝑣

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ΔSuniv>0 then ΔGsys<0

spontaneous process

Δsuniv<0 then ΔGsys>0

non spontaneous process

Page 14: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Student Question

Free Energy

Hold the rubber band a short distance from your lips.

Quickly stretch it and press it against your lips carefully

(don’t hurt those delicate lips). Do you experience a

warming or cooling sensation? Carefully release the

rubber band and experience the sensation. Is stretching

a spontaneous or a non-spontaneous process? What are

the correct signs for ΔG, ΔH, and ΔS when you allow the

rubber band to relax?

14

ΔG ΔH ΔS

a) – + +

b) – – +

c) + + –

d) + – –

Page 15: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Hess’s Law / 3rd Law of Thermo

Hess’s Law: A reaction enthalpy/free

energy/entropy is the sum of the enthalpies/free

energies/entropies of any sequence of reactions

(at the same temperature and pressure) into

which the overall reaction can be divided.

Things to remember:

If you add reactions together, add ΔH/ΔG/ΔS.

If you flip a reaction, flip the sign of ΔH/ΔG/ΔS.

If you multiply a reaction by a constant, multiply

ΔH/ΔG/ΔS by the same constant.

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Page 16: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Student Question

Hess’s Law / 3rd Law of Thermo

What is ΔG° for SO2(g) + ½O2(g) SO3(g) given

the following information?

2S(s) + 3O2(g) 2SO3(g) ΔG° = -742 𝑘𝐽

𝑚𝑜𝑙

S(s) + O2(g) SO2(g) ΔG° = -300. 𝑘𝐽

𝑚𝑜𝑙

a) -71 𝑘𝐽

𝑚𝑜𝑙

b) -442 𝑘𝐽

𝑚𝑜𝑙

c) -671 𝑘𝐽

𝑚𝑜𝑙

d) -1042 𝑘𝐽

𝑚𝑜𝑙

e) None of the above

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Page 17: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Hess’s Law / 3rd Law of Thermo

Thermodynamic Data at 298 K

Substance ΔHf° (𝒌𝑱

𝒎𝒐𝒍) ΔGf° ( 𝒌𝑱

𝒎𝒐𝒍) S° ( 𝑱

𝒎𝒐𝒍∙𝑲)

C2H4(g) 52 68 219

CH4(g) -75 -51 186

CO2(g) -393.5 -394 214

C2H6(g) -84.7 -32.9 229.5

O(g) -110.5 -137 198

O2(g) 0 0 205.

CH3CO2H(l) -484 -389 160.

CH3OH(g) -201 -163 240.

CH3CH2OH(l) -278 -175 161

C6H12O6(s) -1275 -911 212

HCl(g) -92 -95 187

H2(g) 0 0 131

H2O(l) -286 -237 70

H2O(g) -242 -229 189

Fe(s) 0 0 27

Thermodynamic Data at 298 K

Substance ΔHf° (𝒌𝑱

𝒎𝒐𝒍) ΔGf° ( 𝒌𝑱

𝒎𝒐𝒍) S° ( 𝑱

𝒎𝒐𝒍∙𝑲)

Fe2O3(s) -826 -740. 90.

N2(g) 0 0 192

NO2(g) 34 52 240.

NO(g) 90. 87 211

N2O4(g) 10. 98 304

NH3(g) -46 -17 193

HNO3(l) -174 -81 156

NH4Cl(s) -314 -203 96

O2(g) 0 0 205

P4O10(s) -2984 -2698 229

H3PO4(s) -1279 -1119 110

Srhombic(s) 0 0 32

H2S(g) -21 -34 206

SO2(g) -297 -300 248

SO3(g) -396 -371 257

17

* Other ΔH°f , ΔG°f , and S° can be found in appendix 4 in the back of your book.

Page 18: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Hess’s Law / 3rd Law of Thermo

What is ∆𝑆𝑟𝑥𝑛° for

4NH3(g) + 5O2(g) 4NO(g) + 6H2O(l)?

∆𝑆𝑟𝑥𝑛° = σ𝑆𝑝𝑟𝑜𝑑

° − σ𝑆𝑟𝑒𝑎𝑐𝑡°

∆𝑆𝑟𝑥𝑛° = 𝑛𝑁𝑂𝑆𝑁𝑂

° + 𝑛𝐻2𝑂𝑆𝐻2𝑂° −𝑛𝑁𝐻3 𝑆𝑁𝐻3

° − 𝑛𝑂2𝑆𝑂2°

∆𝑆𝑟𝑥𝑛° = 4 211 𝐽

𝑚𝑜𝑙∙𝐾+ 6 70. 𝐽

𝑚𝑜𝑙∙𝐾−

4 193 𝐽

𝑚𝑜𝑙∙𝐾− 5 205 𝐽

𝑚𝑜𝑙∙𝐾= −533 𝐽

𝑚𝑜𝑙∙𝐾

18

Thermodynamic Data at 298 K

Substance ΔHf°𝒌𝑱

𝒎𝒐𝒍ΔGf°

𝒌𝑱

𝒎𝒐𝒍S°

𝑱

𝒎𝒐𝒍∙𝑲

NH3(g) -46 -17 193

O2(g) 0 0 205.

NO(g) 90. 87 211

H2O(l) -286 -237 70.

Page 19: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Student Question

Equilibrium

Consider the reaction: C(graphite) + CO2(g) ⇌ 2CO(g)

What is ΔG ( 𝑘𝐽

𝑚𝑜𝑙) at 25°C when the pressures

are: 𝑃𝐶𝑂 = 0.00050 𝑎𝑡𝑚, 𝑃𝐶𝑂2 = 20. 𝑎𝑡𝑚.

a) 212 𝑘𝐽

𝑚𝑜𝑙b) 120 𝑘𝐽

𝑚𝑜𝑙

c) 116 𝑘𝐽

𝑚𝑜𝑙d) 93.7 𝑘𝐽

𝑚𝑜𝑙

e) None of the above

19

Thermodynamic Data at 298 K

Substance ΔHf°𝒌𝑱

𝒎𝒐𝒍S°

𝑱

𝒎𝒐𝒍∙𝑲

C(graphite) 0 5.74

CO2(g) -393.5 214

CO(g) -110.5 198

Page 20: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Equilibrium

For the reaction below at equilibrium

there are many more products then

reactants. What is the sign of ΔG˚?

A(g) B(g)

20

Page 21: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Take Away from Chapter 10

Big Idea: The change in free energy of a reaction indicates

whether a reaction is spontaneous. In any spontaneous

process there is always an increase in the entropy of the

universe.

Entropy Know how positional probability and energy probability effects

entropy (12,19,&40)

Be able to predict the sign of ΔS (7,& 43)

Be able to calculate S of a system with known number of microstates

𝑆 = 𝑘𝑏𝑙𝑛 Ω

Be able to calculate Δ𝑆 = 𝑆𝑓 − 𝑆𝑖 (29,30,33,48,&49)

∆𝑆 =𝑞

𝑇(constant temperature)

∆𝑆 = 𝐶𝑙𝑛𝑇2

𝑇1(changing temperature)

ΔS of Physical Reactions Know how to calculate ΔS for physical reactions at constant pressure

(31)

Know that a similar multi step process that is used to calculate ΔS

during physical reactions can be used for ΔH. (32)

21

Numbers correspond to end of chapter questions.Problems 23 and 25 review from last chapter.

Page 22: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Take Away from Chapter 10

Isothermal Process Know that for an isothermal expansion of an ideal gas ΔE=0

Know that the maximum work is done for the reversible

expansion/contraction of an ideal gas. (28)

𝑤𝑟𝑒𝑣 = −𝑛𝑅𝑇𝑙𝑛𝑉2

𝑉1

𝑞𝑟𝑒𝑣 = 𝑛𝑅𝑇𝑙𝑛𝑉2

𝑉1(27)

2nd Law of Thermo A spontaneous change is accompanied by an increase in the total

entropy of the universe.

ΔSuni +, spontaneous

ΔSuni −, non spontaneous

Δ𝑆𝑢𝑛𝑖 = Δ𝑆𝑠𝑦𝑠 + Δ𝑆𝑠𝑢𝑟𝑟 (41&50)

Δ𝑆𝑠𝑢𝑟𝑟 = −Δ𝐻

𝑇(at constant pressure)

22

Numbers correspond to end of chapter questions.

Page 23: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Take Away from Chapter 10

Free Energy Be able to calculate the change in free energy (ΔG)

∆𝐺 = ∆𝐻 − 𝑇∆𝑆 (51,56,57,& 64)

Know that ΔH and ΔS are relatively temperature independent while

∆𝐺 is temperature dependent. Therefore, the equation above can

be use to calculate ΔG at different temperatures

Know implications of the sign of ΔG

ΔGsys is +, non spontaneous

ΔGsys is –, spontaneous

Hess’s Law / 3rd Law of Thermo Know that Hess’s Law can be applied to ΔG and ΔS as well as ΔH

Know how to get ΔS˚rxn and ΔG˚rxn from other known ΔS˚rxn and

ΔG˚rxn (62)

Know how to get ΔS˚rxn and ΔG˚rxn from table (54,60,61)

∆𝐺𝑟𝑥𝑛° = σ∆𝐺𝑓

° 𝑝𝑟𝑜𝑑 − σ∆𝐺𝑓°(𝑟𝑒𝑎𝑐) (59)

∆𝑆𝑟𝑥𝑛° = σ𝑆𝑝𝑟𝑜𝑑

° − σ𝑆𝑟𝑒𝑎𝑐° (44)

Know that while absolute values of H and G cannot be calculated, an

absolute value of S can.

3rd Law Thermodynamics: The entropy of a perfect crystal is 0 K is 0

23

Numbers correspond to end of chapter questions.

Page 24: Chapter 10: PhenomenaNote: In order for a reversible process to occur the system must be at equilibrium during the entire process. re 1 P 2 P 1 4 P 1 ∞Step Isothermal Expansion V

Chapter 10: Spontaneity, Entropy, and Free Energy

Take Away from Chapter 10

Equilibrium Know that Q and ΔG are related by

∆𝐺 = ∆𝐺° + 𝑅𝑇𝑙𝑛(𝑄)(68,69,70,& 71)

This equation only changes concentration and not temperature ΔG° must be for the temperature of interest

ΔG is +, reverse reaction spontaneous

ΔG is -, forward reaction spontaneous

ΔG is 0, at equilibrium

Know that K and ΔG° are related by

∆𝐺° = −𝑅𝑇𝑙𝑛(𝐾) (74,78,79,84,86,87,88,91,&109)

ΔG ° = 0, (K=1) equal amounts of products and reactants at equilibrium

ΔG ° > 1, (K<1) more reactants than products at equilibrium

ΔG ° < 1, (K>1) more products than reactants at equilibrium

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Numbers correspond to end of chapter questions.