SlideShare a Scribd company logo
Chapter 18
Thermodynamics
and Equilibrium
Contents and Concepts
1. First Law of Thermodynamics
Spontaneous Processes and Entropy
A spontaneous process is one that occurs by itself.
As we will see, the entropy of the system
increases in a spontaneous process.
2. Entropy and the Second Law of
Thermodynamics
3. Standard Entropies and the Third Law of
Thermodynamics
Copyright © Cengage Learning. All rights reserved.

18 | 2
Free−Energy Concept
The quantity ∆H – T∆S can function as a criterion
for the spontaneity of a reaction at constant
temperature, T, and pressure, P. By defining a
quantity called the free energy, G = H – TS, we
find that ∆G equals the quantity ∆H – T∆S, so the
free energy gives us a thermodynamic criterion of
spontaneity.
4. Free Energy and Spontaneity
5. Interpretation of Free Energy
Copyright © Cengage Learning. All rights reserved.

18 | 3
Free Energy and Equilibrium Constants
The total free energy of the substances in a
reaction mixture decreases as the reaction
proceeds. As we discuss, the standard
free−energy change for a reaction is related to its
equilibrium constant.
6. Relating ∆G° to the Equilibrium Constant
7. Change of Free Energy with Temperature

Copyright © Cengage Learning. All rights reserved.

18 | 4
Learning Objectives

1. First Law of Thermodynamics; Enthalpy
a. Define internal energy, state function,
work, and first law of thermodynamics.
b. Explain why the work done by the system
as a result of expansion or contraction
during a chemical reaction is −P∆V.

Copyright © Cengage Learning. All rights reserved.

18 | 5
1. First Law of Thermodynamics; Enthalpy
(cont.)
c. Relate the change of internal energy, ∆U,
and heat of reaction, q.
d. Define enthalpy, H.
e. Show how heat of reaction at constant
pressure, qp, equals the change of
enthalpy, ∆H.

Copyright © Cengage Learning. All rights reserved.

18 | 6
Spontaneous Processes and Entropy
2. Entropy and the Second Law of
Thermodynamics
a. Define spontaneous process.
b. Define entropy.
c. Relate entropy to disorder in a molecular
system (energy dispersal).
d. State the second law of thermodynamics in
terms of system plus surroundings.

Copyright © Cengage Learning. All rights reserved.

18 | 7
2. Entropy and the Second Law of
Thermodynamics (cont.)
e. State the second law of thermodynamics in
terms of the system only.
f. Calculate the entropy change for a phase
transition.
g. Describe how ∆H − T∆S functions as a
criterion of a spontaneous reaction.

Copyright © Cengage Learning. All rights reserved.

18 | 8
3. Standard Entropies and the Third Law of
Thermodynamics
a. State the third law of thermodynamics.
b. Define standard entropy (absolute
entropy).
c. State the situations in which the entropy
usually increases.
d. Predict the sign of the entropy change of a
reaction.
e. Express the standard change of entropy of
a reaction in terms of standard entropies of
products and reactants.
f. Calculate ∆So for a reaction.
Copyright © Cengage Learning. All rights reserved.

18 | 9
Free−Energy Concept
4. Free Energy and Spontaneity
a. Define free energy, G.
b. Define the standard free−energy change.
c. Calculate ∆Go from ∆Ho and ∆So.
d. Define the standard free energy of
formation, ∆Go.
e. Calculate ∆Go from standard free energies
of formation.
f. State the rules for using ∆Go as a criterion
for spontaneity.
g. Interpret the sign of ∆Go.
Copyright © Cengage Learning. All rights reserved.

18 | 10
5. Interpretation of Free Energy
a. Relate the free−energy change to
maximum useful work.
b. Describe how the free energy changes
during a chemical reaction.

Copyright © Cengage Learning. All rights reserved.

18 | 11
Free Energy and Equilibrium Constants
6. Relating ∆Go to the Equilibrium Constant
a. Define the thermodynamic equilibrium
constant, K.
b. Write the expression for a thermodynamic
equilibrium constant.
c. Indicate how the free−energy change of a
reaction and the reaction quotient are
related.

Copyright © Cengage Learning. All rights reserved.

18 | 12
6. Relating ∆Go to the Equilibrium Constant
(cont.)
d. Relate the standard free−energy change to
the thermodynamic equilibrium constant.
e. Calculate K from the standard free−energy
change (molecular equation).
f. Calculate K from the standard free−energy
change (net ionic equation).

Copyright © Cengage Learning. All rights reserved.

18 | 13
7. Change of Free Energy with Temperature
a. Describe how ∆Go at a given temperature
(∆GoT) is approximately related to ∆Ho and
∆So at that temperature.
b. Describe how the spontaneity or
nonspontaneity of a reaction is related to
each of the four possible combinations of
signs of ∆Ho and ∆So.
c. Calculate ∆Go and K at various
temperatures.
Copyright © Cengage Learning. All rights reserved.

18 | 14
Thermodynamics is the study of heat and other
forms of energy involved in chemical or physical
processes.

Copyright © Cengage Learning. All rights reserved.

18 | 15
First Law of Thermodynamics
The first law of thermodynamics is essentially the
law of conservation of energy applied to a
thermodynamic system.
Recall that the internal energy, U, is the sum of
the kinetic and potential energies of the particles
making up the system:
∆U = Uf – Ui

Copyright © Cengage Learning. All rights reserved.

18 | 16
Exchanges of energy
between the system and its
surroundings are of two
types: heat, q, and work, w.
Putting this in an equation
gives us the first law of
thermodynamics.
∆U = q + w

Copyright © Cengage Learning. All rights reserved.

18 | 17
Sign Convention for q
When heat is evolved by the system, q is negative.
This decreases the internal energy of the system.
When heat is absorbed by the system, q is
positive. This increases the internal energy of the
system.

Copyright © Cengage Learning. All rights reserved.

18 | 18
Sign Convention for w
Recall from Chapter 6 that w = –P∆V.
When the system expands, ∆V is positive, so w is
negative. The system does work on the
surroundings, which decreases the internal energy
of the system.
When the system contracts, ∆V is negative, so w is
positive. The surroundings do work on the system,
which increases the internal energy of the system.
Copyright © Cengage Learning. All rights reserved.

18 | 19
Here the system expands and evolves heat from A
to B.

Zn2+(aq) + 2Cl−(aq) + H2(g)
∆V is positive, so work is negative.
Copyright © Cengage Learning. All rights reserved.

18 | 20
At constant pressure: qP = ∆H
The first law of thermodynamics can now be
expressed as follows:
∆U = ∆H – P∆V

Copyright © Cengage Learning. All rights reserved.

18 | 21
To understand why a chemical reaction goes in a
particular direction, we need to study spontaneous
processes.
A spontaneous process is a physical or chemical
change that occurs by itself. It does not require
any outside force, and it continues until equilibrium
is reached.

Copyright © Cengage Learning. All rights reserved.

18 | 22
Copyright © Cengage Learning. All rights reserved.

18 | 23
The first law of thermodynamics cannot help us to
determine whether a reaction is spontaneous as
written.
We need a new quantity—entropy.
Entropy, S, is a thermodynamic quantity that is a
measure of how dispersed the energy of a system
is among the different possible ways that system
can contain energy.

Copyright © Cengage Learning. All rights reserved.

18 | 24
Examining some spontaneous processes will
clarify this definition.
First, heat energy from a cup of hot coffee
spontaneously flows to its surroundings—the table
top, the air around the cup, or your hand holding
the cup. The entropy of the system (the cup of hot
coffee) and its surroundings has increased.

Copyright © Cengage Learning. All rights reserved.

18 | 25
The rock rolling down the hill is a bit more
complicated. As it rolls down, the rock’s potential
energy is converted to kinetic energy. As it collides
with other rocks on the way down, it transfers
energy to them. The entropy of the system (the
rock) and its surroundings has increased.

Copyright © Cengage Learning. All rights reserved.

18 | 26
Now consider a gas in a flask connected to an
equal−sized flask that is evacuated. When the
stopcock is open, the gas will flow into the
evacuated flask. The kinetic energy has spread
out, and the entropy of the system has increased.

Copyright © Cengage Learning. All rights reserved.

18 | 27
In each of the preceding examples, energy has
been dispersed (that is, spread out).

Copyright © Cengage Learning. All rights reserved.

18 | 28
Entropy is a state function. It depends on
variables, such as temperature and pressure, that
determine the state of the substance.
Entropy is an extensive property. It depends on the
amount of substance present.

Copyright © Cengage Learning. All rights reserved.

18 | 29
Entropy is measured in units of J/K.
Entropy change is calculated as follows:
∆S = Sf – Si

Copyright © Cengage Learning. All rights reserved.

18 | 30
Concept Check 18.1
You have a sample of 1.0 mg of solid iodine at room
temperature. Later, you notice that the iodine has
sublimed (passed into the vapor state). What can
you say about the change of entropy of the iodine?

The iodine has spread out, so its entropy has
increased.

Copyright © Cengage Learning. All rights reserved.

18 | 31
Second Law of Thermodynamics
The total entropy of a system and its surroundings
always increases for a spontaneous process.
Note: Entropy is a measure of energy dispersal,
not a measure of energy itself.

Copyright © Cengage Learning. All rights reserved.

18 | 32
For a spontaneous process at a constant
temperature, we can state the second law of
thermodynamics in terms of only the system:
q
∆S = entropy created +
T

For a spontaneous process:
q
∆S > T

Copyright © Cengage Learning. All rights reserved.

18 | 33
A

C

B

A pendulum is put in motion, with all of its molecules
moving in the same direction, as shown in Figures A and B.
As it moves, the pendulum collides with air molecules.
When it comes to rest in Figure C, the pendulum has
dispersed its energy. This is a spontaneous process.
Copyright © Cengage Learning. All rights reserved.

18 | 34
D

E

F

Now consider the reverse process, which is not
spontaneous. While this process does not violate the first
law of thermodynamics, it does violate the second law
because the dispersed energy becomes more concentrated
as the molecules move together.
Copyright © Cengage Learning. All rights reserved.

18 | 35
Entropy and Molecular Disorder
Entropy is essentially related to energy dispersal.
The entropy of a molecular system may be
concentrated in a few energy states and later
dispersed among many more energy states. The
energy of such a system increases.

Copyright © Cengage Learning. All rights reserved.

18 | 36
In the case of the cup of hot coffee, as heat moves
from the hot coffee, molecular motion becomes
more disordered. In becoming more disordered,
the energy is more dispersed.

Copyright © Cengage Learning. All rights reserved.

18 | 37
Likewise, when the gas moves from one container
into the evacuated container, molecules become
more disordered because they are dispersed over
a larger volume. The energy of the system is
dispersed over a larger volume.

Copyright © Cengage Learning. All rights reserved.

18 | 38
When ice melts, the molecules become more
disordered, again dispersing energy more widely.
When one molecule decomposes to give two, as in
N2O4(g) → 2NO2(g)
more disorder is created because the two
molecules produced can move independently of
each other. Energy is more dispersed.

Copyright © Cengage Learning. All rights reserved.

18 | 39
In each of these cases, molecular disorder
increases, as does entropy.
Note: This understanding of entropy as disorder
applies only to molecular situations in which
increasing disorder increases the dispersion of
energy. It cannot be applied to situations that are
not molecular—such as a desk.

Copyright © Cengage Learning. All rights reserved.

18 | 40
Entropy Change for a Phase Transition
In a phase transition process that occurs very
close to equilibrium, heat is very slowly absorbed
or evolved. Under these conditions, no significant
new entropy is created.
q
∆S =
T

This concept can be applied to melting using ∆Hfus
for q and to vaporization using ∆Hvap for q.
Copyright © Cengage Learning. All rights reserved.

18 | 41
?

Acetone, CH3COCH3, is a volatile liquid
solvent; it is used in nail polish, for
example. The standard enthalpy of
formation, ∆Hf°, of the liquid at 25°C is
–247.6 kJ/mol; the same quantity for
the vapor is –216.6 kJ/mol.
What is the entropy change when 1.00
mol liquid acetone vaporizes at 25°C?

Copyright © Cengage Learning. All rights reserved.

18 | 42
CH3COCH3(l) → CH3COCH3(g)
∆Hf°
n
n∆Hf°

–247.6 kJ/mol

–216.6 kJ/mol

1 mol
–247.6 kJ

1 mol
–216.6 kJ

∆H° = 31.0 kJ

∆H
ΔS =
T

31.0 × 10 3 J
ΔS =
298 K
∆S = 104 J/K
Copyright © Cengage Learning. All rights reserved.

18 | 43
Criterion for a Spontaneous Reaction
The criterion is that the entropy of the system and
its surroundings must increase.
q
ΔS >
T
ΔH
ΔS >
T

TΔS > ΔH

0 > Δ H - TΔ S or Δ H - TΔ S < 0

Copyright © Cengage Learning. All rights reserved.

18 | 44
Third Law of Thermodynamics
A substance that is perfectly crystalline at zero
Kelvin (0 K) has an entropy of zero.

Copyright © Cengage Learning. All rights reserved.

18 | 45
The standard entropy of a substance—its absolute
entropy, S°—is the entropy value for the standard
state of the species. The standard state is
indicated with the superscript degree sign.
For a pure substance, its standard state is 1 atm
pressure. For a substance in solution, its standard
state is a 1 M solution.

Copyright © Cengage Learning. All rights reserved.

18 | 46
Copyright © Cengage Learning. All rights reserved.

18 | 47
Copyright © Cengage Learning. All rights reserved.

18 | 48
Standard Entropy of Bromine, Br2, at Various Temperatures

Copyright © Cengage Learning. All rights reserved.

18 | 49
Entropy Change for a Reaction
Entropy usually increases in three situations:
1. A reaction in which a molecule is broken into
two or more smaller molecules.
2. A reaction in which there is an increase in
the number of moles of a gas.
3. A process in which a solid changes to a
liquid or gas or a liquid changes to a gas.

Copyright © Cengage Learning. All rights reserved.

18 | 50
The opening of Chapter 6, on
thermo−chemistry, describes the
endothermic reaction of solid barium
hydroxide octahydrate and solid
ammonium nitrate:
Ba(OH)2  8H2O(s) + 2NH4NO3(s) →
2NH3(g) + 10H2O(l) + Ba(NO3)2(aq)
Predict the sign of ∆S° for this reaction.

?

3 moles of reactants produces 13 moles of
products. Solid reactants produce gaseous,
liquid, and aqueous products.
∆S° is positive.
Copyright © Cengage Learning. All rights reserved.

18 | 51
To compute ∆S° where n = moles:
ΔS =


∑ nS



(products) −

Copyright © Cengage Learning. All rights reserved.

∑ nS



(reactants)

18 | 52
When wine is exposed to air in the
presence of certain bacteria, the ethyl
alcohol is oxidized to acetic acid, giving
vinegar. Calculate the entropy change
at 25°C for the following similar
reaction:
CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l)

?

The standard entropies, S°, of the
substances in J/(K  mol) at 25°C are
CH3CH2OH(l),161; O2(g), 205;
CH3COOH(l), 160; H2O(l), 69.9.
Copyright © Cengage Learning. All rights reserved.

18 | 53
CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l)
S°
161
J/(mol  K)
n mol
1
nS° J/K
161
366

205

160

69.9

1
205

1
160

1
69.9

229.9

∆S = 229.9 J/K – 366 J/K
∆S = –136 J/K
Copyright © Cengage Learning. All rights reserved.

18 | 54
Free Energy and Spontaneity
Physicist J. Willard Gibbs introduced the concept
of free energy, G. Free energy is a
thermodynamic quantity defined as follows:
G = H – TS

Copyright © Cengage Learning. All rights reserved.

18 | 55
As a reaction proceeds, G changes:
∆G = ∆H – T∆S
Standard free energy change:
∆G° = ∆H° – T∆S°

Copyright © Cengage Learning. All rights reserved.

18 | 56
?

Using standard enthalpies of formation,
∆Hf° and the value of ∆S° from the
previous problem, calculate ∆G° for the
oxidation of ethyl alcohol to acetic acid.

CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l)

Copyright © Cengage Learning. All rights reserved.

18 | 57
CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l)
∆Hf° kJ/mol –277.6
n mol
n∆Hf° kJ

0

1
1
–277.6 0
–277.6 kJ

–487.0

–285.8

1
–487.0

1
–285.8
–772.8 kJ

∆H° = –495.2 kJ
∆S° = –136 J/K
T = 298 K
Copyright © Cengage Learning. All rights reserved.

18 | 58
∆H° = –495.2 kJ
∆S° = –136 J/K = –0.136 kJ/K
T = 298 K
∆G° = ∆H° – T∆S°
∆G° = –495.2 kJ – (298 K)(–0.136 kJ/K)
∆G° = –495.2 kJ + 40.5 kJ
∆G° = –454.7 kJ
The reaction is spontaneous.

Copyright © Cengage Learning. All rights reserved.

18 | 59
Standard Free Energies of Formation, ∆Gf°
The standard free energy of formation is the
free−energy change that occurs when 1 mol of
substance is formed from its elements in their
standard states at 1 atm and at a specified
temperature, usually 25°C.
The corresponding reaction for the standard free
energy of formation is the same as that for
standard enthalpy of formation, ∆Hf°.

Copyright © Cengage Learning. All rights reserved.

18 | 60
Copyright © Cengage Learning. All rights reserved.

18 | 61
Copyright © Cengage Learning. All rights reserved.

18 | 62
To find the standard free energy change for a
reaction where n = moles:
ΔG =


∑ nΔG (products) − ∑ nΔG (reactants)


Copyright © Cengage Learning. All rights reserved.



18 | 63
?

Calculate the free−energy change,
∆G°, for the oxidation of ethyl alcohol
to acetic acid using standard free
energies of formation.

CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l)

Copyright © Cengage Learning. All rights reserved.

18 | 64
CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l)
∆Gf°, kJ/mol
237.2
n, mol
n∆Gf°, kJ
237.2

–174.8

0

1
1
–174.8
0
–174.8 kJ

–392.5

–

1
1
–392.5
–
–629.7 kJ

∆G° = –629.7 – (–174.8)
∆G° = –454.9 kJ
Copyright © Cengage Learning. All rights reserved.

18 | 65
∆G° as a Criterion for Spontaneity
The spontaneity of a reaction can now be
determined by the sign of ∆G°.
∆G° < –10 kJ: spontaneous
∆G° > +10 kJ: nonspontaneous
∆G° = very small or zero (< +10 kJ and
> –10 kJ): at equilibrium
Copyright © Cengage Learning. All rights reserved.

18 | 66
Concept Check 18.2
Consider the reaction of nitrogen, N2, and oxygen,
O2, to form nitrogen monoxide, NO:
N2(g) + O2(g) → 2NO(g)
From the standard free energy of formation of NO,
what can you say about thisreaction?
For the reaction as written, ∆G° = 173.20 kJ.
For 1 mol NO(g), ∆Gf° = 86.60 kJ/mol.
The reaction is nonspontaneous.

Copyright © Cengage Learning. All rights reserved.

18 | 67
Copyright © Cengage Learning. All rights reserved.

18 | 68
Copyright © Cengage Learning. All rights reserved.

18 | 69
Interpreting Free Energy
Theoretically, spontaneous reactions can be used
to perform useful work. In fact, we use reactions
such as the combustion of gasoline to move a
vehicle.
We can also use spontaneous reactions to provide
the energy needed for a nonspontaneous reaction.
The maximum useful work is
wmax = ∆G
Copyright © Cengage Learning. All rights reserved.

18 | 70
The thermodynamic equilibrium constant is the
equilibrium constant in which the concentrations of
gases are expressed as partial pressures in
atmospheres and the concentrations of solutes in
solutions are expressed in molarities.
If only gases are present, K = Kp.
If only solutes in liquid solution are present, K = Kc.

Copyright © Cengage Learning. All rights reserved.

18 | 71
?

Write the expression for the
thermodynamic equilibrium constant for
these reactions:
a. N2O4(g)  2NO2(g)
b. Zn(s) + 2H+(aq)  Zn2+(aq) + H2(g)
a.

b.

Copyright © Cengage Learning. All rights reserved.

K=

K=

2
PNO2

PN2O 4
[Zn 2+ ] PH

2

[H + ] 2

18 | 72
Standard free energy change is related to the
thermodynamic equilibrium constant, K, at
equilibrium:
∆G = ∆G° + RT ln Q
At equilibrium:
∆G = 0 and Q = K
∆G° = –RT ln K

Copyright © Cengage Learning. All rights reserved.

18 | 73
?

Calculate the value of the
thermodynamic equilibrium constant at
25°C for the reaction
N2O4(g)  2NO2(g)
The standard free energy of formation
at 25°C is 51.30 kJ/mol for NO2(g) and
97.82 kJ/mol for N2O4(g).

∆G° = 2 mol(51.30 kJ/mol) – 1 mol(97.82 kJ/mol)
∆G° = 102.60 kJ – 97.82 kJ
∆G° = 4.78 kJ
Copyright © Cengage Learning. All rights reserved.

18 | 74
∆G = –RT ln K
− ∆G
ln K =
RT

J 

3
−  4.78 × 10
÷
mol 

ln K =
J
8.315
(298 K)
mol K
ln K = −1.929
K = 0.145
Copyright © Cengage Learning. All rights reserved.

18 | 75
?

Sodium carbonate, Na2CO3, can be
prepared by heating sodium hydrogen
carbonate, NaHCO3:

2NaHCO3(s) → Na2CO3(s) + H2O(g) + CO2(g)
Estimate the temperature at which the
reaction proceeds spontaneously at 1 atm.
See Appendix C for data.

Copyright © Cengage Learning. All rights reserved.

18 | 76
2NaHCO3(s) → Na2CO3(s) + H2O(g) + CO(g)
∆Hf°, kJ/mol –947.7 –1130.8 –241.8
–393.5
n, mol
2
1
1
1
n∆Hf°, kJ –1895.4 –1130.8 –241.8
–393.5
–1895.4 kJ
–1766.1 kJ
∆H° = 129.3 kJ
Sf°, J/mol  K 102
n, mol
2
nSf°, J/K
204
204 J/K

139
1
139

188.7
1
188.7

541.4 J/K
∆S° = 337.4 J/K

Copyright © Cengage Learning. All rights reserved.

213.7
1
213.7

18 | 77
ΔH °
T =
ΔS °

129.3 × 10 3 J
T=
J
337.4
K

T = 383 K

T = 110°C
Copyright © Cengage Learning. All rights reserved.

18 | 78

More Related Content

What's hot

stress and strain
stress and strainstress and strain
stress and strain
COMSATS Abbottabad
 
Brief concepts of chemical equilibrium
Brief concepts  of   chemical  equilibrium Brief concepts  of   chemical  equilibrium
Brief concepts of chemical equilibrium
AnzaDar3
 
Chemical equilibrium
Chemical equilibriumChemical equilibrium
Equilibrium
EquilibriumEquilibrium
Equilibrium
Atul Saini
 
Solutions and Colligative properties
Solutions and Colligative propertiesSolutions and Colligative properties
Solutions and Colligative properties
khali29
 
Simple harmonic motion
Simple harmonic motionSimple harmonic motion
Simple harmonic motion
Praveen Koushley
 
Capillary Action
Capillary Action Capillary Action
Capillary Action
University of Gujrat
 
Surface tension.pptx
Surface tension.pptxSurface tension.pptx
Surface tension.pptx
Aditibarman2
 
surface tension
surface tensionsurface tension
surface tension
Afaq Wajid
 
ROTATION OF RIGID BODIES
ROTATION OF RIGID BODIESROTATION OF RIGID BODIES
ROTATION OF RIGID BODIES
shahzadebaujiti
 
Hess’s law of constant heat summation
Hess’s law of constant heat summationHess’s law of constant heat summation
Hess’s law of constant heat summation
Muhammad Mujeeb
 
Phase diagram of a one component system ( water system )
Phase diagram of a one component system ( water system )Phase diagram of a one component system ( water system )
Phase diagram of a one component system ( water system )
ShahriarTipu1
 
COLLIGATIVE PROPERTIES OF SOLUTIONS.pptx
COLLIGATIVE PROPERTIES OF SOLUTIONS.pptxCOLLIGATIVE PROPERTIES OF SOLUTIONS.pptx
COLLIGATIVE PROPERTIES OF SOLUTIONS.pptx
Alihassan856272
 
Colloids By Sitwat Rafi
Colloids By Sitwat RafiColloids By Sitwat Rafi
Colloids By Sitwat Rafi
Sitvat Rafi
 
Liquid crystal
Liquid crystalLiquid crystal
Liquid crystal
Afia Riaz
 
Hydrodynamics
HydrodynamicsHydrodynamics
Hydrodynamics
mridulagm
 
The kinetic theory of gases
The kinetic theory of gasesThe kinetic theory of gases
The kinetic theory of gases
Ashwani Kumar
 
Colligative properties ppt ssc,amt
Colligative properties ppt ssc,amtColligative properties ppt ssc,amt
Colligative properties ppt ssc,amt
Nitin Bansod
 
Solid state
Solid stateSolid state
Solid state
Mirza Salman Baig
 
Colligative properties
Colligative properties Colligative properties
Colligative properties
R.Karthikeyan - Vivekananda College
 

What's hot (20)

stress and strain
stress and strainstress and strain
stress and strain
 
Brief concepts of chemical equilibrium
Brief concepts  of   chemical  equilibrium Brief concepts  of   chemical  equilibrium
Brief concepts of chemical equilibrium
 
Chemical equilibrium
Chemical equilibriumChemical equilibrium
Chemical equilibrium
 
Equilibrium
EquilibriumEquilibrium
Equilibrium
 
Solutions and Colligative properties
Solutions and Colligative propertiesSolutions and Colligative properties
Solutions and Colligative properties
 
Simple harmonic motion
Simple harmonic motionSimple harmonic motion
Simple harmonic motion
 
Capillary Action
Capillary Action Capillary Action
Capillary Action
 
Surface tension.pptx
Surface tension.pptxSurface tension.pptx
Surface tension.pptx
 
surface tension
surface tensionsurface tension
surface tension
 
ROTATION OF RIGID BODIES
ROTATION OF RIGID BODIESROTATION OF RIGID BODIES
ROTATION OF RIGID BODIES
 
Hess’s law of constant heat summation
Hess’s law of constant heat summationHess’s law of constant heat summation
Hess’s law of constant heat summation
 
Phase diagram of a one component system ( water system )
Phase diagram of a one component system ( water system )Phase diagram of a one component system ( water system )
Phase diagram of a one component system ( water system )
 
COLLIGATIVE PROPERTIES OF SOLUTIONS.pptx
COLLIGATIVE PROPERTIES OF SOLUTIONS.pptxCOLLIGATIVE PROPERTIES OF SOLUTIONS.pptx
COLLIGATIVE PROPERTIES OF SOLUTIONS.pptx
 
Colloids By Sitwat Rafi
Colloids By Sitwat RafiColloids By Sitwat Rafi
Colloids By Sitwat Rafi
 
Liquid crystal
Liquid crystalLiquid crystal
Liquid crystal
 
Hydrodynamics
HydrodynamicsHydrodynamics
Hydrodynamics
 
The kinetic theory of gases
The kinetic theory of gasesThe kinetic theory of gases
The kinetic theory of gases
 
Colligative properties ppt ssc,amt
Colligative properties ppt ssc,amtColligative properties ppt ssc,amt
Colligative properties ppt ssc,amt
 
Solid state
Solid stateSolid state
Solid state
 
Colligative properties
Colligative properties Colligative properties
Colligative properties
 

Viewers also liked

3 myp chemistry atomic structure
3 myp chemistry atomic structure3 myp chemistry atomic structure
3 myp chemistry atomic structure
Green Lake School
 
Introduction to Sedimentary Structures - Part 2
Introduction to Sedimentary Structures - Part 2Introduction to Sedimentary Structures - Part 2
Introduction to Sedimentary Structures - Part 2
William W. Little
 
Introduction to Sedimentology and Stratigraphy
Introduction to Sedimentology and StratigraphyIntroduction to Sedimentology and Stratigraphy
Introduction to Sedimentology and Stratigraphy
William W. Little
 
River transportation processes
River transportation processesRiver transportation processes
River transportation processes
nuruljimmy1211
 
Introduction to Sedimentary Structures - Part 1
Introduction to Sedimentary Structures - Part 1Introduction to Sedimentary Structures - Part 1
Introduction to Sedimentary Structures - Part 1
William W. Little
 
River Presentation
River PresentationRiver Presentation
River Presentation
Malia Damit
 
Sediment transport
Sediment transportSediment transport
Sediment transport
Mohsin Siddique
 
Fluvial Process And Related Land Forms
Fluvial Process And Related Land Forms Fluvial Process And Related Land Forms
Fluvial Process And Related Land Forms
sileshi
 
Principles of Stratigraphy
Principles of StratigraphyPrinciples of Stratigraphy
Principles of Stratigraphy
William W. Little
 
Sedimentary depositional environments
Sedimentary depositional environmentsSedimentary depositional environments
Sedimentary depositional environments
uos
 

Viewers also liked (10)

3 myp chemistry atomic structure
3 myp chemistry atomic structure3 myp chemistry atomic structure
3 myp chemistry atomic structure
 
Introduction to Sedimentary Structures - Part 2
Introduction to Sedimentary Structures - Part 2Introduction to Sedimentary Structures - Part 2
Introduction to Sedimentary Structures - Part 2
 
Introduction to Sedimentology and Stratigraphy
Introduction to Sedimentology and StratigraphyIntroduction to Sedimentology and Stratigraphy
Introduction to Sedimentology and Stratigraphy
 
River transportation processes
River transportation processesRiver transportation processes
River transportation processes
 
Introduction to Sedimentary Structures - Part 1
Introduction to Sedimentary Structures - Part 1Introduction to Sedimentary Structures - Part 1
Introduction to Sedimentary Structures - Part 1
 
River Presentation
River PresentationRiver Presentation
River Presentation
 
Sediment transport
Sediment transportSediment transport
Sediment transport
 
Fluvial Process And Related Land Forms
Fluvial Process And Related Land Forms Fluvial Process And Related Land Forms
Fluvial Process And Related Land Forms
 
Principles of Stratigraphy
Principles of StratigraphyPrinciples of Stratigraphy
Principles of Stratigraphy
 
Sedimentary depositional environments
Sedimentary depositional environmentsSedimentary depositional environments
Sedimentary depositional environments
 

Similar to Chapter18

3 thermodynamics of pharmaceutical systems
3 thermodynamics of pharmaceutical systems3 thermodynamics of pharmaceutical systems
3 thermodynamics of pharmaceutical systems
University of Zambia, School of Pharmacy, Lusaka, Zambia
 
Bioenergetics2_For online class.pdf
Bioenergetics2_For online class.pdfBioenergetics2_For online class.pdf
Bioenergetics2_For online class.pdf
AshyanaSaeed
 
Thermodynamics and kinetics
Thermodynamics and kineticsThermodynamics and kinetics
Thermodynamics and kinetics
ShelbyRocks
 
chapter_19 General Chemistry: Thermodynamics and Equilbrium
chapter_19 General Chemistry: Thermodynamics and Equilbriumchapter_19 General Chemistry: Thermodynamics and Equilbrium
chapter_19 General Chemistry: Thermodynamics and Equilbrium
mrqueenscience
 
Thermodynamics and laws of thermodynamics and osmotic or diffusion
Thermodynamics and laws of thermodynamics and osmotic or diffusionThermodynamics and laws of thermodynamics and osmotic or diffusion
Thermodynamics and laws of thermodynamics and osmotic or diffusion
moazamaakbar
 
ET QB UNIT 1.pdf
ET QB UNIT 1.pdfET QB UNIT 1.pdf
ET QB UNIT 1.pdf
RAMESHBABU725
 
ET QB UNIT 1.pdf
ET QB UNIT 1.pdfET QB UNIT 1.pdf
ET QB UNIT 1.pdf
RameshbabuRrb
 
thermodynamics ppt.pptx
thermodynamics ppt.pptxthermodynamics ppt.pptx
thermodynamics ppt.pptx
HarshitShah679949
 
First law of thermodynamics
First law of thermodynamicsFirst law of thermodynamics
First law of thermodynamics
MattSmith321834
 
Basic of thermodynamics section a
Basic of thermodynamics  section aBasic of thermodynamics  section a
Basic of thermodynamics section a
Akshit Kohli
 
Thermo-DSY-Unit-3--1.pptx
Thermo-DSY-Unit-3--1.pptxThermo-DSY-Unit-3--1.pptx
Thermo-DSY-Unit-3--1.pptx
YogeshMokaddamPatil
 
Thermodynamics by KK Sahu sir
Thermodynamics by KK Sahu sirThermodynamics by KK Sahu sir
Thermodynamics by KK Sahu sir
KAUSHAL SAHU
 
MUHAMMAD NASIR
MUHAMMAD NASIRMUHAMMAD NASIR
MUHAMMAD NASIR
Muhammad Nasir
 
nasir
nasirnasir
4
44
Thermodynamics and Heat Transfer
Thermodynamics and Heat TransferThermodynamics and Heat Transfer
Thermodynamics and Heat Transfer
Manish Kumar
 
Basic thermodynamics
Basic thermodynamicsBasic thermodynamics
Basic thermodynamics
SACHINNikam39
 
Chemical Engineering desciption, laws.ppt
Chemical Engineering desciption, laws.pptChemical Engineering desciption, laws.ppt
Chemical Engineering desciption, laws.ppt
EminaKarahmet1
 
1 handout.ppt
1 handout.ppt1 handout.ppt
1 handout.ppt
RanendraRoy2
 
Principle of bioenergetics & photobiology and photosynthesis
Principle of bioenergetics & photobiology and photosynthesisPrinciple of bioenergetics & photobiology and photosynthesis
Principle of bioenergetics & photobiology and photosynthesis
Dr Kirpa Ram Jangra
 

Similar to Chapter18 (20)

3 thermodynamics of pharmaceutical systems
3 thermodynamics of pharmaceutical systems3 thermodynamics of pharmaceutical systems
3 thermodynamics of pharmaceutical systems
 
Bioenergetics2_For online class.pdf
Bioenergetics2_For online class.pdfBioenergetics2_For online class.pdf
Bioenergetics2_For online class.pdf
 
Thermodynamics and kinetics
Thermodynamics and kineticsThermodynamics and kinetics
Thermodynamics and kinetics
 
chapter_19 General Chemistry: Thermodynamics and Equilbrium
chapter_19 General Chemistry: Thermodynamics and Equilbriumchapter_19 General Chemistry: Thermodynamics and Equilbrium
chapter_19 General Chemistry: Thermodynamics and Equilbrium
 
Thermodynamics and laws of thermodynamics and osmotic or diffusion
Thermodynamics and laws of thermodynamics and osmotic or diffusionThermodynamics and laws of thermodynamics and osmotic or diffusion
Thermodynamics and laws of thermodynamics and osmotic or diffusion
 
ET QB UNIT 1.pdf
ET QB UNIT 1.pdfET QB UNIT 1.pdf
ET QB UNIT 1.pdf
 
ET QB UNIT 1.pdf
ET QB UNIT 1.pdfET QB UNIT 1.pdf
ET QB UNIT 1.pdf
 
thermodynamics ppt.pptx
thermodynamics ppt.pptxthermodynamics ppt.pptx
thermodynamics ppt.pptx
 
First law of thermodynamics
First law of thermodynamicsFirst law of thermodynamics
First law of thermodynamics
 
Basic of thermodynamics section a
Basic of thermodynamics  section aBasic of thermodynamics  section a
Basic of thermodynamics section a
 
Thermo-DSY-Unit-3--1.pptx
Thermo-DSY-Unit-3--1.pptxThermo-DSY-Unit-3--1.pptx
Thermo-DSY-Unit-3--1.pptx
 
Thermodynamics by KK Sahu sir
Thermodynamics by KK Sahu sirThermodynamics by KK Sahu sir
Thermodynamics by KK Sahu sir
 
MUHAMMAD NASIR
MUHAMMAD NASIRMUHAMMAD NASIR
MUHAMMAD NASIR
 
nasir
nasirnasir
nasir
 
4
44
4
 
Thermodynamics and Heat Transfer
Thermodynamics and Heat TransferThermodynamics and Heat Transfer
Thermodynamics and Heat Transfer
 
Basic thermodynamics
Basic thermodynamicsBasic thermodynamics
Basic thermodynamics
 
Chemical Engineering desciption, laws.ppt
Chemical Engineering desciption, laws.pptChemical Engineering desciption, laws.ppt
Chemical Engineering desciption, laws.ppt
 
1 handout.ppt
1 handout.ppt1 handout.ppt
1 handout.ppt
 
Principle of bioenergetics & photobiology and photosynthesis
Principle of bioenergetics & photobiology and photosynthesisPrinciple of bioenergetics & photobiology and photosynthesis
Principle of bioenergetics & photobiology and photosynthesis
 

More from Dr Robert Craig PhD

Hofstra Living environment Dr Rob
Hofstra Living environment Dr RobHofstra Living environment Dr Rob
Hofstra Living environment Dr Rob
Dr Robert Craig PhD
 
pdf (4) 4.pdf
pdf (4) 4.pdfpdf (4) 4.pdf
pdf (4) 4.pdf
Dr Robert Craig PhD
 
Mastering_Assignments.pdf.pdf
Mastering_Assignments.pdf.pdfMastering_Assignments.pdf.pdf
Mastering_Assignments.pdf.pdf
Dr Robert Craig PhD
 
Lecture3.pdf
Lecture3.pdfLecture3.pdf
Lecture3.pdf
Dr Robert Craig PhD
 
Lecture2.pdf
Lecture2.pdfLecture2.pdf
Lecture2.pdf
Dr Robert Craig PhD
 
Lecture0.pdf
Lecture0.pdfLecture0.pdf
Lecture0.pdf
Dr Robert Craig PhD
 
lecture 11 of 12 ves 1.pptx
lecture 11 of 12 ves 1.pptxlecture 11 of 12 ves 1.pptx
lecture 11 of 12 ves 1.pptx
Dr Robert Craig PhD
 
Chapter 2-Your text book ves 5.pptx
Chapter 2-Your text book ves 5.pptxChapter 2-Your text book ves 5.pptx
Chapter 2-Your text book ves 5.pptx
Dr Robert Craig PhD
 
Brown dwarfs and planets jaslyn.pdf
Brown dwarfs and planets jaslyn.pdfBrown dwarfs and planets jaslyn.pdf
Brown dwarfs and planets jaslyn.pdf
Dr Robert Craig PhD
 
Day 1 Martin file from syllabus ves 5.pptx
Day 1 Martin file from syllabus ves 5.pptxDay 1 Martin file from syllabus ves 5.pptx
Day 1 Martin file from syllabus ves 5.pptx
Dr Robert Craig PhD
 
Astronomy chapter 1 power point.pptx
Astronomy chapter 1 power point.pptxAstronomy chapter 1 power point.pptx
Astronomy chapter 1 power point.pptx
Dr Robert Craig PhD
 
5Page43 how to classify stars parkslope heard from Annie.pdf
5Page43 how to classify stars parkslope  heard from Annie.pdf5Page43 how to classify stars parkslope  heard from Annie.pdf
5Page43 how to classify stars parkslope heard from Annie.pdf
Dr Robert Craig PhD
 
1-D Kinematics AP Lab Graphing.docx
1-D Kinematics AP Lab Graphing.docx1-D Kinematics AP Lab Graphing.docx
1-D Kinematics AP Lab Graphing.docx
Dr Robert Craig PhD
 
03 - Average Rates of Changec Cameron 1 Sara Hill.pdf
03 - Average Rates of Changec Cameron 1 Sara Hill.pdf03 - Average Rates of Changec Cameron 1 Sara Hill.pdf
03 - Average Rates of Changec Cameron 1 Sara Hill.pdf
Dr Robert Craig PhD
 
5.4- Measuring the Earth with Eratosthenes. Ves 2.pdf
5.4- Measuring the Earth with Eratosthenes. Ves 2.pdf5.4- Measuring the Earth with Eratosthenes. Ves 2.pdf
5.4- Measuring the Earth with Eratosthenes. Ves 2.pdf
Dr Robert Craig PhD
 
4.6- The Wanderers ves 7.pptx
4.6- The Wanderers ves 7.pptx4.6- The Wanderers ves 7.pptx
4.6- The Wanderers ves 7.pptx
Dr Robert Craig PhD
 
chapter 2 redone parkslope ves 4.pdf
chapter 2 redone parkslope ves 4.pdfchapter 2 redone parkslope ves 4.pdf
chapter 2 redone parkslope ves 4.pdf
Dr Robert Craig PhD
 
4.6- The Wanderers ves 7.pptx
4.6- The Wanderers ves 7.pptx4.6- The Wanderers ves 7.pptx
4.6- The Wanderers ves 7.pptx
Dr Robert Craig PhD
 
season_path_of_the_sun_and_latitude.pdf
season_path_of_the_sun_and_latitude.pdfseason_path_of_the_sun_and_latitude.pdf
season_path_of_the_sun_and_latitude.pdf
Dr Robert Craig PhD
 

More from Dr Robert Craig PhD (20)

Hofstra Living environment Dr Rob
Hofstra Living environment Dr RobHofstra Living environment Dr Rob
Hofstra Living environment Dr Rob
 
pdf (4) 4.pdf
pdf (4) 4.pdfpdf (4) 4.pdf
pdf (4) 4.pdf
 
Mastering_Assignments.pdf.pdf
Mastering_Assignments.pdf.pdfMastering_Assignments.pdf.pdf
Mastering_Assignments.pdf.pdf
 
Lecture3.pdf
Lecture3.pdfLecture3.pdf
Lecture3.pdf
 
Lecture2.pdf
Lecture2.pdfLecture2.pdf
Lecture2.pdf
 
Lecture0.pdf
Lecture0.pdfLecture0.pdf
Lecture0.pdf
 
lecture 11 of 12 ves 1.pptx
lecture 11 of 12 ves 1.pptxlecture 11 of 12 ves 1.pptx
lecture 11 of 12 ves 1.pptx
 
Chapter 2-Your text book ves 5.pptx
Chapter 2-Your text book ves 5.pptxChapter 2-Your text book ves 5.pptx
Chapter 2-Your text book ves 5.pptx
 
Brown dwarfs and planets jaslyn.pdf
Brown dwarfs and planets jaslyn.pdfBrown dwarfs and planets jaslyn.pdf
Brown dwarfs and planets jaslyn.pdf
 
Day 1 Martin file from syllabus ves 5.pptx
Day 1 Martin file from syllabus ves 5.pptxDay 1 Martin file from syllabus ves 5.pptx
Day 1 Martin file from syllabus ves 5.pptx
 
Astronomy chapter 1 power point.pptx
Astronomy chapter 1 power point.pptxAstronomy chapter 1 power point.pptx
Astronomy chapter 1 power point.pptx
 
5Page43 how to classify stars parkslope heard from Annie.pdf
5Page43 how to classify stars parkslope  heard from Annie.pdf5Page43 how to classify stars parkslope  heard from Annie.pdf
5Page43 how to classify stars parkslope heard from Annie.pdf
 
1-D Kinematics AP Lab Graphing.docx
1-D Kinematics AP Lab Graphing.docx1-D Kinematics AP Lab Graphing.docx
1-D Kinematics AP Lab Graphing.docx
 
03 - Average Rates of Changec Cameron 1 Sara Hill.pdf
03 - Average Rates of Changec Cameron 1 Sara Hill.pdf03 - Average Rates of Changec Cameron 1 Sara Hill.pdf
03 - Average Rates of Changec Cameron 1 Sara Hill.pdf
 
5.4- Measuring the Earth with Eratosthenes. Ves 2.pdf
5.4- Measuring the Earth with Eratosthenes. Ves 2.pdf5.4- Measuring the Earth with Eratosthenes. Ves 2.pdf
5.4- Measuring the Earth with Eratosthenes. Ves 2.pdf
 
4.6- The Wanderers ves 7.pptx
4.6- The Wanderers ves 7.pptx4.6- The Wanderers ves 7.pptx
4.6- The Wanderers ves 7.pptx
 
Physics chapter 1.docx
Physics chapter 1.docxPhysics chapter 1.docx
Physics chapter 1.docx
 
chapter 2 redone parkslope ves 4.pdf
chapter 2 redone parkslope ves 4.pdfchapter 2 redone parkslope ves 4.pdf
chapter 2 redone parkslope ves 4.pdf
 
4.6- The Wanderers ves 7.pptx
4.6- The Wanderers ves 7.pptx4.6- The Wanderers ves 7.pptx
4.6- The Wanderers ves 7.pptx
 
season_path_of_the_sun_and_latitude.pdf
season_path_of_the_sun_and_latitude.pdfseason_path_of_the_sun_and_latitude.pdf
season_path_of_the_sun_and_latitude.pdf
 

Recently uploaded

Cosa hanno in comune un mattoncino Lego e la backdoor XZ?
Cosa hanno in comune un mattoncino Lego e la backdoor XZ?Cosa hanno in comune un mattoncino Lego e la backdoor XZ?
Cosa hanno in comune un mattoncino Lego e la backdoor XZ?
Speck&Tech
 
Removing Uninteresting Bytes in Software Fuzzing
Removing Uninteresting Bytes in Software FuzzingRemoving Uninteresting Bytes in Software Fuzzing
Removing Uninteresting Bytes in Software Fuzzing
Aftab Hussain
 
Video Streaming: Then, Now, and in the Future
Video Streaming: Then, Now, and in the FutureVideo Streaming: Then, Now, and in the Future
Video Streaming: Then, Now, and in the Future
Alpen-Adria-Universität
 
Presentation of the OECD Artificial Intelligence Review of Germany
Presentation of the OECD Artificial Intelligence Review of GermanyPresentation of the OECD Artificial Intelligence Review of Germany
Presentation of the OECD Artificial Intelligence Review of Germany
innovationoecd
 
20240605 QFM017 Machine Intelligence Reading List May 2024
20240605 QFM017 Machine Intelligence Reading List May 202420240605 QFM017 Machine Intelligence Reading List May 2024
20240605 QFM017 Machine Intelligence Reading List May 2024
Matthew Sinclair
 
Driving Business Innovation: Latest Generative AI Advancements & Success Story
Driving Business Innovation: Latest Generative AI Advancements & Success StoryDriving Business Innovation: Latest Generative AI Advancements & Success Story
Driving Business Innovation: Latest Generative AI Advancements & Success Story
Safe Software
 
Communications Mining Series - Zero to Hero - Session 1
Communications Mining Series - Zero to Hero - Session 1Communications Mining Series - Zero to Hero - Session 1
Communications Mining Series - Zero to Hero - Session 1
DianaGray10
 
Mind map of terminologies used in context of Generative AI
Mind map of terminologies used in context of Generative AIMind map of terminologies used in context of Generative AI
Mind map of terminologies used in context of Generative AI
Kumud Singh
 
Mariano G Tinti - Decoding SpaceX
Mariano G Tinti - Decoding SpaceXMariano G Tinti - Decoding SpaceX
Mariano G Tinti - Decoding SpaceX
Mariano Tinti
 
Best 20 SEO Techniques To Improve Website Visibility In SERP
Best 20 SEO Techniques To Improve Website Visibility In SERPBest 20 SEO Techniques To Improve Website Visibility In SERP
Best 20 SEO Techniques To Improve Website Visibility In SERP
Pixlogix Infotech
 
HCL Notes and Domino License Cost Reduction in the World of DLAU
HCL Notes and Domino License Cost Reduction in the World of DLAUHCL Notes and Domino License Cost Reduction in the World of DLAU
HCL Notes and Domino License Cost Reduction in the World of DLAU
panagenda
 
GraphSummit Singapore | Neo4j Product Vision & Roadmap - Q2 2024
GraphSummit Singapore | Neo4j Product Vision & Roadmap - Q2 2024GraphSummit Singapore | Neo4j Product Vision & Roadmap - Q2 2024
GraphSummit Singapore | Neo4j Product Vision & Roadmap - Q2 2024
Neo4j
 
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAU
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUHCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAU
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAU
panagenda
 
Climate Impact of Software Testing at Nordic Testing Days
Climate Impact of Software Testing at Nordic Testing DaysClimate Impact of Software Testing at Nordic Testing Days
Climate Impact of Software Testing at Nordic Testing Days
Kari Kakkonen
 
Uni Systems Copilot event_05062024_C.Vlachos.pdf
Uni Systems Copilot event_05062024_C.Vlachos.pdfUni Systems Copilot event_05062024_C.Vlachos.pdf
Uni Systems Copilot event_05062024_C.Vlachos.pdf
Uni Systems S.M.S.A.
 
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!
SOFTTECHHUB
 
みなさんこんにちはこれ何文字まで入るの?40文字以下不可とか本当に意味わからないけどこれ限界文字数書いてないからマジでやばい文字数いけるんじゃないの?えこ...
みなさんこんにちはこれ何文字まで入るの?40文字以下不可とか本当に意味わからないけどこれ限界文字数書いてないからマジでやばい文字数いけるんじゃないの?えこ...みなさんこんにちはこれ何文字まで入るの?40文字以下不可とか本当に意味わからないけどこれ限界文字数書いてないからマジでやばい文字数いけるんじゃないの?えこ...
みなさんこんにちはこれ何文字まで入るの?40文字以下不可とか本当に意味わからないけどこれ限界文字数書いてないからマジでやばい文字数いけるんじゃないの?えこ...
名前 です男
 
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...
SOFTTECHHUB
 
Introduction to CHERI technology - Cybersecurity
Introduction to CHERI technology - CybersecurityIntroduction to CHERI technology - Cybersecurity
Introduction to CHERI technology - Cybersecurity
mikeeftimakis1
 
20240609 QFM020 Irresponsible AI Reading List May 2024
20240609 QFM020 Irresponsible AI Reading List May 202420240609 QFM020 Irresponsible AI Reading List May 2024
20240609 QFM020 Irresponsible AI Reading List May 2024
Matthew Sinclair
 

Recently uploaded (20)

Cosa hanno in comune un mattoncino Lego e la backdoor XZ?
Cosa hanno in comune un mattoncino Lego e la backdoor XZ?Cosa hanno in comune un mattoncino Lego e la backdoor XZ?
Cosa hanno in comune un mattoncino Lego e la backdoor XZ?
 
Removing Uninteresting Bytes in Software Fuzzing
Removing Uninteresting Bytes in Software FuzzingRemoving Uninteresting Bytes in Software Fuzzing
Removing Uninteresting Bytes in Software Fuzzing
 
Video Streaming: Then, Now, and in the Future
Video Streaming: Then, Now, and in the FutureVideo Streaming: Then, Now, and in the Future
Video Streaming: Then, Now, and in the Future
 
Presentation of the OECD Artificial Intelligence Review of Germany
Presentation of the OECD Artificial Intelligence Review of GermanyPresentation of the OECD Artificial Intelligence Review of Germany
Presentation of the OECD Artificial Intelligence Review of Germany
 
20240605 QFM017 Machine Intelligence Reading List May 2024
20240605 QFM017 Machine Intelligence Reading List May 202420240605 QFM017 Machine Intelligence Reading List May 2024
20240605 QFM017 Machine Intelligence Reading List May 2024
 
Driving Business Innovation: Latest Generative AI Advancements & Success Story
Driving Business Innovation: Latest Generative AI Advancements & Success StoryDriving Business Innovation: Latest Generative AI Advancements & Success Story
Driving Business Innovation: Latest Generative AI Advancements & Success Story
 
Communications Mining Series - Zero to Hero - Session 1
Communications Mining Series - Zero to Hero - Session 1Communications Mining Series - Zero to Hero - Session 1
Communications Mining Series - Zero to Hero - Session 1
 
Mind map of terminologies used in context of Generative AI
Mind map of terminologies used in context of Generative AIMind map of terminologies used in context of Generative AI
Mind map of terminologies used in context of Generative AI
 
Mariano G Tinti - Decoding SpaceX
Mariano G Tinti - Decoding SpaceXMariano G Tinti - Decoding SpaceX
Mariano G Tinti - Decoding SpaceX
 
Best 20 SEO Techniques To Improve Website Visibility In SERP
Best 20 SEO Techniques To Improve Website Visibility In SERPBest 20 SEO Techniques To Improve Website Visibility In SERP
Best 20 SEO Techniques To Improve Website Visibility In SERP
 
HCL Notes and Domino License Cost Reduction in the World of DLAU
HCL Notes and Domino License Cost Reduction in the World of DLAUHCL Notes and Domino License Cost Reduction in the World of DLAU
HCL Notes and Domino License Cost Reduction in the World of DLAU
 
GraphSummit Singapore | Neo4j Product Vision & Roadmap - Q2 2024
GraphSummit Singapore | Neo4j Product Vision & Roadmap - Q2 2024GraphSummit Singapore | Neo4j Product Vision & Roadmap - Q2 2024
GraphSummit Singapore | Neo4j Product Vision & Roadmap - Q2 2024
 
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAU
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUHCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAU
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAU
 
Climate Impact of Software Testing at Nordic Testing Days
Climate Impact of Software Testing at Nordic Testing DaysClimate Impact of Software Testing at Nordic Testing Days
Climate Impact of Software Testing at Nordic Testing Days
 
Uni Systems Copilot event_05062024_C.Vlachos.pdf
Uni Systems Copilot event_05062024_C.Vlachos.pdfUni Systems Copilot event_05062024_C.Vlachos.pdf
Uni Systems Copilot event_05062024_C.Vlachos.pdf
 
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!
 
みなさんこんにちはこれ何文字まで入るの?40文字以下不可とか本当に意味わからないけどこれ限界文字数書いてないからマジでやばい文字数いけるんじゃないの?えこ...
みなさんこんにちはこれ何文字まで入るの?40文字以下不可とか本当に意味わからないけどこれ限界文字数書いてないからマジでやばい文字数いけるんじゃないの?えこ...みなさんこんにちはこれ何文字まで入るの?40文字以下不可とか本当に意味わからないけどこれ限界文字数書いてないからマジでやばい文字数いけるんじゃないの?えこ...
みなさんこんにちはこれ何文字まで入るの?40文字以下不可とか本当に意味わからないけどこれ限界文字数書いてないからマジでやばい文字数いけるんじゃないの?えこ...
 
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...
 
Introduction to CHERI technology - Cybersecurity
Introduction to CHERI technology - CybersecurityIntroduction to CHERI technology - Cybersecurity
Introduction to CHERI technology - Cybersecurity
 
20240609 QFM020 Irresponsible AI Reading List May 2024
20240609 QFM020 Irresponsible AI Reading List May 202420240609 QFM020 Irresponsible AI Reading List May 2024
20240609 QFM020 Irresponsible AI Reading List May 2024
 

Chapter18

  • 2. Contents and Concepts 1. First Law of Thermodynamics Spontaneous Processes and Entropy A spontaneous process is one that occurs by itself. As we will see, the entropy of the system increases in a spontaneous process. 2. Entropy and the Second Law of Thermodynamics 3. Standard Entropies and the Third Law of Thermodynamics Copyright © Cengage Learning. All rights reserved. 18 | 2
  • 3. Free−Energy Concept The quantity ∆H – T∆S can function as a criterion for the spontaneity of a reaction at constant temperature, T, and pressure, P. By defining a quantity called the free energy, G = H – TS, we find that ∆G equals the quantity ∆H – T∆S, so the free energy gives us a thermodynamic criterion of spontaneity. 4. Free Energy and Spontaneity 5. Interpretation of Free Energy Copyright © Cengage Learning. All rights reserved. 18 | 3
  • 4. Free Energy and Equilibrium Constants The total free energy of the substances in a reaction mixture decreases as the reaction proceeds. As we discuss, the standard free−energy change for a reaction is related to its equilibrium constant. 6. Relating ∆G° to the Equilibrium Constant 7. Change of Free Energy with Temperature Copyright © Cengage Learning. All rights reserved. 18 | 4
  • 5. Learning Objectives 1. First Law of Thermodynamics; Enthalpy a. Define internal energy, state function, work, and first law of thermodynamics. b. Explain why the work done by the system as a result of expansion or contraction during a chemical reaction is −P∆V. Copyright © Cengage Learning. All rights reserved. 18 | 5
  • 6. 1. First Law of Thermodynamics; Enthalpy (cont.) c. Relate the change of internal energy, ∆U, and heat of reaction, q. d. Define enthalpy, H. e. Show how heat of reaction at constant pressure, qp, equals the change of enthalpy, ∆H. Copyright © Cengage Learning. All rights reserved. 18 | 6
  • 7. Spontaneous Processes and Entropy 2. Entropy and the Second Law of Thermodynamics a. Define spontaneous process. b. Define entropy. c. Relate entropy to disorder in a molecular system (energy dispersal). d. State the second law of thermodynamics in terms of system plus surroundings. Copyright © Cengage Learning. All rights reserved. 18 | 7
  • 8. 2. Entropy and the Second Law of Thermodynamics (cont.) e. State the second law of thermodynamics in terms of the system only. f. Calculate the entropy change for a phase transition. g. Describe how ∆H − T∆S functions as a criterion of a spontaneous reaction. Copyright © Cengage Learning. All rights reserved. 18 | 8
  • 9. 3. Standard Entropies and the Third Law of Thermodynamics a. State the third law of thermodynamics. b. Define standard entropy (absolute entropy). c. State the situations in which the entropy usually increases. d. Predict the sign of the entropy change of a reaction. e. Express the standard change of entropy of a reaction in terms of standard entropies of products and reactants. f. Calculate ∆So for a reaction. Copyright © Cengage Learning. All rights reserved. 18 | 9
  • 10. Free−Energy Concept 4. Free Energy and Spontaneity a. Define free energy, G. b. Define the standard free−energy change. c. Calculate ∆Go from ∆Ho and ∆So. d. Define the standard free energy of formation, ∆Go. e. Calculate ∆Go from standard free energies of formation. f. State the rules for using ∆Go as a criterion for spontaneity. g. Interpret the sign of ∆Go. Copyright © Cengage Learning. All rights reserved. 18 | 10
  • 11. 5. Interpretation of Free Energy a. Relate the free−energy change to maximum useful work. b. Describe how the free energy changes during a chemical reaction. Copyright © Cengage Learning. All rights reserved. 18 | 11
  • 12. Free Energy and Equilibrium Constants 6. Relating ∆Go to the Equilibrium Constant a. Define the thermodynamic equilibrium constant, K. b. Write the expression for a thermodynamic equilibrium constant. c. Indicate how the free−energy change of a reaction and the reaction quotient are related. Copyright © Cengage Learning. All rights reserved. 18 | 12
  • 13. 6. Relating ∆Go to the Equilibrium Constant (cont.) d. Relate the standard free−energy change to the thermodynamic equilibrium constant. e. Calculate K from the standard free−energy change (molecular equation). f. Calculate K from the standard free−energy change (net ionic equation). Copyright © Cengage Learning. All rights reserved. 18 | 13
  • 14. 7. Change of Free Energy with Temperature a. Describe how ∆Go at a given temperature (∆GoT) is approximately related to ∆Ho and ∆So at that temperature. b. Describe how the spontaneity or nonspontaneity of a reaction is related to each of the four possible combinations of signs of ∆Ho and ∆So. c. Calculate ∆Go and K at various temperatures. Copyright © Cengage Learning. All rights reserved. 18 | 14
  • 15. Thermodynamics is the study of heat and other forms of energy involved in chemical or physical processes. Copyright © Cengage Learning. All rights reserved. 18 | 15
  • 16. First Law of Thermodynamics The first law of thermodynamics is essentially the law of conservation of energy applied to a thermodynamic system. Recall that the internal energy, U, is the sum of the kinetic and potential energies of the particles making up the system: ∆U = Uf – Ui Copyright © Cengage Learning. All rights reserved. 18 | 16
  • 17. Exchanges of energy between the system and its surroundings are of two types: heat, q, and work, w. Putting this in an equation gives us the first law of thermodynamics. ∆U = q + w Copyright © Cengage Learning. All rights reserved. 18 | 17
  • 18. Sign Convention for q When heat is evolved by the system, q is negative. This decreases the internal energy of the system. When heat is absorbed by the system, q is positive. This increases the internal energy of the system. Copyright © Cengage Learning. All rights reserved. 18 | 18
  • 19. Sign Convention for w Recall from Chapter 6 that w = –P∆V. When the system expands, ∆V is positive, so w is negative. The system does work on the surroundings, which decreases the internal energy of the system. When the system contracts, ∆V is negative, so w is positive. The surroundings do work on the system, which increases the internal energy of the system. Copyright © Cengage Learning. All rights reserved. 18 | 19
  • 20. Here the system expands and evolves heat from A to B. Zn2+(aq) + 2Cl−(aq) + H2(g) ∆V is positive, so work is negative. Copyright © Cengage Learning. All rights reserved. 18 | 20
  • 21. At constant pressure: qP = ∆H The first law of thermodynamics can now be expressed as follows: ∆U = ∆H – P∆V Copyright © Cengage Learning. All rights reserved. 18 | 21
  • 22. To understand why a chemical reaction goes in a particular direction, we need to study spontaneous processes. A spontaneous process is a physical or chemical change that occurs by itself. It does not require any outside force, and it continues until equilibrium is reached. Copyright © Cengage Learning. All rights reserved. 18 | 22
  • 23. Copyright © Cengage Learning. All rights reserved. 18 | 23
  • 24. The first law of thermodynamics cannot help us to determine whether a reaction is spontaneous as written. We need a new quantity—entropy. Entropy, S, is a thermodynamic quantity that is a measure of how dispersed the energy of a system is among the different possible ways that system can contain energy. Copyright © Cengage Learning. All rights reserved. 18 | 24
  • 25. Examining some spontaneous processes will clarify this definition. First, heat energy from a cup of hot coffee spontaneously flows to its surroundings—the table top, the air around the cup, or your hand holding the cup. The entropy of the system (the cup of hot coffee) and its surroundings has increased. Copyright © Cengage Learning. All rights reserved. 18 | 25
  • 26. The rock rolling down the hill is a bit more complicated. As it rolls down, the rock’s potential energy is converted to kinetic energy. As it collides with other rocks on the way down, it transfers energy to them. The entropy of the system (the rock) and its surroundings has increased. Copyright © Cengage Learning. All rights reserved. 18 | 26
  • 27. Now consider a gas in a flask connected to an equal−sized flask that is evacuated. When the stopcock is open, the gas will flow into the evacuated flask. The kinetic energy has spread out, and the entropy of the system has increased. Copyright © Cengage Learning. All rights reserved. 18 | 27
  • 28. In each of the preceding examples, energy has been dispersed (that is, spread out). Copyright © Cengage Learning. All rights reserved. 18 | 28
  • 29. Entropy is a state function. It depends on variables, such as temperature and pressure, that determine the state of the substance. Entropy is an extensive property. It depends on the amount of substance present. Copyright © Cengage Learning. All rights reserved. 18 | 29
  • 30. Entropy is measured in units of J/K. Entropy change is calculated as follows: ∆S = Sf – Si Copyright © Cengage Learning. All rights reserved. 18 | 30
  • 31. Concept Check 18.1 You have a sample of 1.0 mg of solid iodine at room temperature. Later, you notice that the iodine has sublimed (passed into the vapor state). What can you say about the change of entropy of the iodine? The iodine has spread out, so its entropy has increased. Copyright © Cengage Learning. All rights reserved. 18 | 31
  • 32. Second Law of Thermodynamics The total entropy of a system and its surroundings always increases for a spontaneous process. Note: Entropy is a measure of energy dispersal, not a measure of energy itself. Copyright © Cengage Learning. All rights reserved. 18 | 32
  • 33. For a spontaneous process at a constant temperature, we can state the second law of thermodynamics in terms of only the system: q ∆S = entropy created + T For a spontaneous process: q ∆S > T Copyright © Cengage Learning. All rights reserved. 18 | 33
  • 34. A C B A pendulum is put in motion, with all of its molecules moving in the same direction, as shown in Figures A and B. As it moves, the pendulum collides with air molecules. When it comes to rest in Figure C, the pendulum has dispersed its energy. This is a spontaneous process. Copyright © Cengage Learning. All rights reserved. 18 | 34
  • 35. D E F Now consider the reverse process, which is not spontaneous. While this process does not violate the first law of thermodynamics, it does violate the second law because the dispersed energy becomes more concentrated as the molecules move together. Copyright © Cengage Learning. All rights reserved. 18 | 35
  • 36. Entropy and Molecular Disorder Entropy is essentially related to energy dispersal. The entropy of a molecular system may be concentrated in a few energy states and later dispersed among many more energy states. The energy of such a system increases. Copyright © Cengage Learning. All rights reserved. 18 | 36
  • 37. In the case of the cup of hot coffee, as heat moves from the hot coffee, molecular motion becomes more disordered. In becoming more disordered, the energy is more dispersed. Copyright © Cengage Learning. All rights reserved. 18 | 37
  • 38. Likewise, when the gas moves from one container into the evacuated container, molecules become more disordered because they are dispersed over a larger volume. The energy of the system is dispersed over a larger volume. Copyright © Cengage Learning. All rights reserved. 18 | 38
  • 39. When ice melts, the molecules become more disordered, again dispersing energy more widely. When one molecule decomposes to give two, as in N2O4(g) → 2NO2(g) more disorder is created because the two molecules produced can move independently of each other. Energy is more dispersed. Copyright © Cengage Learning. All rights reserved. 18 | 39
  • 40. In each of these cases, molecular disorder increases, as does entropy. Note: This understanding of entropy as disorder applies only to molecular situations in which increasing disorder increases the dispersion of energy. It cannot be applied to situations that are not molecular—such as a desk. Copyright © Cengage Learning. All rights reserved. 18 | 40
  • 41. Entropy Change for a Phase Transition In a phase transition process that occurs very close to equilibrium, heat is very slowly absorbed or evolved. Under these conditions, no significant new entropy is created. q ∆S = T This concept can be applied to melting using ∆Hfus for q and to vaporization using ∆Hvap for q. Copyright © Cengage Learning. All rights reserved. 18 | 41
  • 42. ? Acetone, CH3COCH3, is a volatile liquid solvent; it is used in nail polish, for example. The standard enthalpy of formation, ∆Hf°, of the liquid at 25°C is –247.6 kJ/mol; the same quantity for the vapor is –216.6 kJ/mol. What is the entropy change when 1.00 mol liquid acetone vaporizes at 25°C? Copyright © Cengage Learning. All rights reserved. 18 | 42
  • 43. CH3COCH3(l) → CH3COCH3(g) ∆Hf° n n∆Hf° –247.6 kJ/mol –216.6 kJ/mol 1 mol –247.6 kJ 1 mol –216.6 kJ ∆H° = 31.0 kJ ∆H ΔS = T 31.0 × 10 3 J ΔS = 298 K ∆S = 104 J/K Copyright © Cengage Learning. All rights reserved. 18 | 43
  • 44. Criterion for a Spontaneous Reaction The criterion is that the entropy of the system and its surroundings must increase. q ΔS > T ΔH ΔS > T TΔS > ΔH 0 > Δ H - TΔ S or Δ H - TΔ S < 0 Copyright © Cengage Learning. All rights reserved. 18 | 44
  • 45. Third Law of Thermodynamics A substance that is perfectly crystalline at zero Kelvin (0 K) has an entropy of zero. Copyright © Cengage Learning. All rights reserved. 18 | 45
  • 46. The standard entropy of a substance—its absolute entropy, S°—is the entropy value for the standard state of the species. The standard state is indicated with the superscript degree sign. For a pure substance, its standard state is 1 atm pressure. For a substance in solution, its standard state is a 1 M solution. Copyright © Cengage Learning. All rights reserved. 18 | 46
  • 47. Copyright © Cengage Learning. All rights reserved. 18 | 47
  • 48. Copyright © Cengage Learning. All rights reserved. 18 | 48
  • 49. Standard Entropy of Bromine, Br2, at Various Temperatures Copyright © Cengage Learning. All rights reserved. 18 | 49
  • 50. Entropy Change for a Reaction Entropy usually increases in three situations: 1. A reaction in which a molecule is broken into two or more smaller molecules. 2. A reaction in which there is an increase in the number of moles of a gas. 3. A process in which a solid changes to a liquid or gas or a liquid changes to a gas. Copyright © Cengage Learning. All rights reserved. 18 | 50
  • 51. The opening of Chapter 6, on thermo−chemistry, describes the endothermic reaction of solid barium hydroxide octahydrate and solid ammonium nitrate: Ba(OH)2  8H2O(s) + 2NH4NO3(s) → 2NH3(g) + 10H2O(l) + Ba(NO3)2(aq) Predict the sign of ∆S° for this reaction. ? 3 moles of reactants produces 13 moles of products. Solid reactants produce gaseous, liquid, and aqueous products. ∆S° is positive. Copyright © Cengage Learning. All rights reserved. 18 | 51
  • 52. To compute ∆S° where n = moles: ΔS =  ∑ nS  (products) − Copyright © Cengage Learning. All rights reserved. ∑ nS  (reactants) 18 | 52
  • 53. When wine is exposed to air in the presence of certain bacteria, the ethyl alcohol is oxidized to acetic acid, giving vinegar. Calculate the entropy change at 25°C for the following similar reaction: CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l) ? The standard entropies, S°, of the substances in J/(K  mol) at 25°C are CH3CH2OH(l),161; O2(g), 205; CH3COOH(l), 160; H2O(l), 69.9. Copyright © Cengage Learning. All rights reserved. 18 | 53
  • 54. CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l) S° 161 J/(mol  K) n mol 1 nS° J/K 161 366 205 160 69.9 1 205 1 160 1 69.9 229.9 ∆S = 229.9 J/K – 366 J/K ∆S = –136 J/K Copyright © Cengage Learning. All rights reserved. 18 | 54
  • 55. Free Energy and Spontaneity Physicist J. Willard Gibbs introduced the concept of free energy, G. Free energy is a thermodynamic quantity defined as follows: G = H – TS Copyright © Cengage Learning. All rights reserved. 18 | 55
  • 56. As a reaction proceeds, G changes: ∆G = ∆H – T∆S Standard free energy change: ∆G° = ∆H° – T∆S° Copyright © Cengage Learning. All rights reserved. 18 | 56
  • 57. ? Using standard enthalpies of formation, ∆Hf° and the value of ∆S° from the previous problem, calculate ∆G° for the oxidation of ethyl alcohol to acetic acid. CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l) Copyright © Cengage Learning. All rights reserved. 18 | 57
  • 58. CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l) ∆Hf° kJ/mol –277.6 n mol n∆Hf° kJ 0 1 1 –277.6 0 –277.6 kJ –487.0 –285.8 1 –487.0 1 –285.8 –772.8 kJ ∆H° = –495.2 kJ ∆S° = –136 J/K T = 298 K Copyright © Cengage Learning. All rights reserved. 18 | 58
  • 59. ∆H° = –495.2 kJ ∆S° = –136 J/K = –0.136 kJ/K T = 298 K ∆G° = ∆H° – T∆S° ∆G° = –495.2 kJ – (298 K)(–0.136 kJ/K) ∆G° = –495.2 kJ + 40.5 kJ ∆G° = –454.7 kJ The reaction is spontaneous. Copyright © Cengage Learning. All rights reserved. 18 | 59
  • 60. Standard Free Energies of Formation, ∆Gf° The standard free energy of formation is the free−energy change that occurs when 1 mol of substance is formed from its elements in their standard states at 1 atm and at a specified temperature, usually 25°C. The corresponding reaction for the standard free energy of formation is the same as that for standard enthalpy of formation, ∆Hf°. Copyright © Cengage Learning. All rights reserved. 18 | 60
  • 61. Copyright © Cengage Learning. All rights reserved. 18 | 61
  • 62. Copyright © Cengage Learning. All rights reserved. 18 | 62
  • 63. To find the standard free energy change for a reaction where n = moles: ΔG =  ∑ nΔG (products) − ∑ nΔG (reactants)  Copyright © Cengage Learning. All rights reserved.  18 | 63
  • 64. ? Calculate the free−energy change, ∆G°, for the oxidation of ethyl alcohol to acetic acid using standard free energies of formation. CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l) Copyright © Cengage Learning. All rights reserved. 18 | 64
  • 65. CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l) ∆Gf°, kJ/mol 237.2 n, mol n∆Gf°, kJ 237.2 –174.8 0 1 1 –174.8 0 –174.8 kJ –392.5 – 1 1 –392.5 – –629.7 kJ ∆G° = –629.7 – (–174.8) ∆G° = –454.9 kJ Copyright © Cengage Learning. All rights reserved. 18 | 65
  • 66. ∆G° as a Criterion for Spontaneity The spontaneity of a reaction can now be determined by the sign of ∆G°. ∆G° < –10 kJ: spontaneous ∆G° > +10 kJ: nonspontaneous ∆G° = very small or zero (< +10 kJ and > –10 kJ): at equilibrium Copyright © Cengage Learning. All rights reserved. 18 | 66
  • 67. Concept Check 18.2 Consider the reaction of nitrogen, N2, and oxygen, O2, to form nitrogen monoxide, NO: N2(g) + O2(g) → 2NO(g) From the standard free energy of formation of NO, what can you say about thisreaction? For the reaction as written, ∆G° = 173.20 kJ. For 1 mol NO(g), ∆Gf° = 86.60 kJ/mol. The reaction is nonspontaneous. Copyright © Cengage Learning. All rights reserved. 18 | 67
  • 68. Copyright © Cengage Learning. All rights reserved. 18 | 68
  • 69. Copyright © Cengage Learning. All rights reserved. 18 | 69
  • 70. Interpreting Free Energy Theoretically, spontaneous reactions can be used to perform useful work. In fact, we use reactions such as the combustion of gasoline to move a vehicle. We can also use spontaneous reactions to provide the energy needed for a nonspontaneous reaction. The maximum useful work is wmax = ∆G Copyright © Cengage Learning. All rights reserved. 18 | 70
  • 71. The thermodynamic equilibrium constant is the equilibrium constant in which the concentrations of gases are expressed as partial pressures in atmospheres and the concentrations of solutes in solutions are expressed in molarities. If only gases are present, K = Kp. If only solutes in liquid solution are present, K = Kc. Copyright © Cengage Learning. All rights reserved. 18 | 71
  • 72. ? Write the expression for the thermodynamic equilibrium constant for these reactions: a. N2O4(g)  2NO2(g) b. Zn(s) + 2H+(aq)  Zn2+(aq) + H2(g) a. b. Copyright © Cengage Learning. All rights reserved. K= K= 2 PNO2 PN2O 4 [Zn 2+ ] PH 2 [H + ] 2 18 | 72
  • 73. Standard free energy change is related to the thermodynamic equilibrium constant, K, at equilibrium: ∆G = ∆G° + RT ln Q At equilibrium: ∆G = 0 and Q = K ∆G° = –RT ln K Copyright © Cengage Learning. All rights reserved. 18 | 73
  • 74. ? Calculate the value of the thermodynamic equilibrium constant at 25°C for the reaction N2O4(g)  2NO2(g) The standard free energy of formation at 25°C is 51.30 kJ/mol for NO2(g) and 97.82 kJ/mol for N2O4(g). ∆G° = 2 mol(51.30 kJ/mol) – 1 mol(97.82 kJ/mol) ∆G° = 102.60 kJ – 97.82 kJ ∆G° = 4.78 kJ Copyright © Cengage Learning. All rights reserved. 18 | 74
  • 75. ∆G = –RT ln K − ∆G ln K = RT J   3 −  4.78 × 10 ÷ mol   ln K = J 8.315 (298 K) mol K ln K = −1.929 K = 0.145 Copyright © Cengage Learning. All rights reserved. 18 | 75
  • 76. ? Sodium carbonate, Na2CO3, can be prepared by heating sodium hydrogen carbonate, NaHCO3: 2NaHCO3(s) → Na2CO3(s) + H2O(g) + CO2(g) Estimate the temperature at which the reaction proceeds spontaneously at 1 atm. See Appendix C for data. Copyright © Cengage Learning. All rights reserved. 18 | 76
  • 77. 2NaHCO3(s) → Na2CO3(s) + H2O(g) + CO(g) ∆Hf°, kJ/mol –947.7 –1130.8 –241.8 –393.5 n, mol 2 1 1 1 n∆Hf°, kJ –1895.4 –1130.8 –241.8 –393.5 –1895.4 kJ –1766.1 kJ ∆H° = 129.3 kJ Sf°, J/mol  K 102 n, mol 2 nSf°, J/K 204 204 J/K 139 1 139 188.7 1 188.7 541.4 J/K ∆S° = 337.4 J/K Copyright © Cengage Learning. All rights reserved. 213.7 1 213.7 18 | 77
  • 78. ΔH ° T = ΔS ° 129.3 × 10 3 J T= J 337.4 K T = 383 K T = 110°C Copyright © Cengage Learning. All rights reserved. 18 | 78

Editor's Notes

  1. Change to Figure 6.11 with no captions or text
  2. Change to Concept Check 18.2