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SOLUTIONS MANUAL FOR

by

Thermodynamicsin

Material Science,Second Edition

Robert DeHoff

8165.indd 1 1/24/08 8:58:07 AM

8165.indd 2 1/24/08 8:54:26 AM

SOLUTIONS MANUAL FOR

by

Thermodynamicsin

Material Science,Second Edition

Robert DeHoff

8165.indd 3 1/24/08 8:58:07 AM

CRC PressTaylor & Francis Group6000 Broken Sound Parkway NW, Suite 300Boca Raton, FL 33487-2742

© 2007 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business

No claim to original U.S. Government worksPrinted in the United States of America on acid-free paper10 9 8 7 6 5 4 3 2 1

International Standard Book Number-13: 978-0-8493-8165-2 (Softcover)

This book contains information obtained from authentic and highly regarded sources Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The Authors and Publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint

Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers.

For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC) 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged.

Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation with-out intent to infringe.

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and the CRC Press Web site athttp://www.crcpress.com

T&F_LOC_C_Master.indd 1 1/24/08 8:50:46 AM8165.indd 4 1/24/08 8:54:27 AM

This Manual is a compilation of solutions to the homework problems presented in thetext:

Thermodynamics in Materials Science, Second Edition, CRC Press, Taylor and Francis Group,

Publishers, ISBN 0-8493-4065-9, (2006).

In preparing this manual the data used in the solutions are consistent with that presentedin the Appendices of the text. The reader should be aware that thermochemical data continues toevolve, so that the numbers may change with time, sometimes significantly. In any real worldapplication in industry or research it is incumbent upon the investigator to seek to obtain thelatest information from appropriate data bases.

Working equations developed in this process use notation that is consistent with that usedin the text. All numerical problems have been worked in MathCadTM, a mathematics softwareprogram, so that every attempt has been made to produce correct answers from the input data andthe strategy devised to solve the problem. All graphical presentations that involve numericalcalculations were also produced in MathCad and copied into this manual. This includes anumber of quantitative surface plots, which are particularly easily generated in this software.

Robert T. DeHoff, July, 2006

Cha

pter

2.

The

Str

uctu

re o

f The

rmod

ynam

ics

1

Cha

pter

2.

Stru

ctur

e of

The

rmod

ynam

ics

2.1.

Cla

ssify

the

follo

win

g th

erm

odyn

amic

syst

ems i

n th

e fiv

eca

tego

ries d

efin

ed in

Sec

tion

2.1:

a. A

solid

bar

of c

oppe

r.b.

A g

lass

of i

ce w

ater

.c.

A y

ttria

stab

ilize

d zi

rcon

ia fu

rnac

e tu

be.

d. A

styr

ofoa

m c

offe

e cu

p.e.

A e

utec

tic a

lloy

turb

ine

blad

e ro

tatin

g at

20,

000

rpm

.

If y

ou fi

nd it

nec

essa

ry to

qua

lify

your

ans

wer

by

defin

ing

the

syst

em m

ore

prec

isel

y, st

ate

your

ass

umpt

ions

.

Ans

wer

to 2

.1.

In e

ach

case

it is

nec

essa

ry to

mak

e so

me

assu

mpt

ions

abo

utth

e ki

nd o

f pro

cess

es th

at m

ay b

e of

inte

rest

in th

e pr

oble

m.

The

sim

ples

t situ

atio

n is

ass

umed

in e

ach

of th

e fo

llow

ing.

a. P

ure

solid

cop

per i

s a u

nary

, hom

ogen

eous

, clo

sed,

non

-re

actin

g ot

herw

ise

sim

ple

syst

em.

b. I

ce w

ater

con

sist

s of t

wo

phas

es, s

olid

and

liqu

id; b

oth

phas

es a

re fi

xed

com

posi

tion.

Thi

s sys

tem

may

be

treat

ed a

s aun

ary,

het

erog

eneo

us, c

lose

d, n

on-r

eact

ing

othe

rwis

e si

mpl

esy

stem

.

c. I

n th

is m

ater

ial s

yste

m th

e yt

tria

(Y2O

3) is

pre

sent

as s

econ

dph

ase

parti

cles

dis

tribu

ted

thro

ugho

ut a

mat

rix o

f ZrO

2. It

may

be tr

eate

d as

a m

ultic

ompo

nent

(bin

ary

if th

e co

mpo

nent

s are

take

n to

be

Y2O

3 and

ZrO

2) he

tero

gene

ous (

two

phas

es),

clos

ed, n

on-r

eact

ing

othe

rwis

e si

mpl

e sy

stem

.

d. S

tyro

foam

is a

pol

ymer

of f

ixed

com

posi

tion.

It m

ay b

eap

prop

riate

to tr

eat i

t as a

una

ry, h

omog

eneo

us, c

lose

d, n

on-

reac

ting

othe

rwis

e si

mpl

e sy

stem

. If

, for

exa

mpl

e, th

e sy

stem

is d

efin

ed to

incl

ude

the

poro

sity

then

add

ition

al (g

aseo

us)

com

pone

nts w

ill b

e pr

esen

t in

thes

e tw

o ph

ases

.

e. A

eut

ectic

syst

em c

onsi

sts o

f alte

rnat

ing

laye

rs o

f tw

oph

ases

, eac

h of

whi

ch is

a so

lid so

lutio

n. T

he p

robl

em a

lso

impo

ses a

cen

trifu

gal f

ield

on

the

rota

ting

part.

Thu

s, th

is is

am

ultic

ompo

nent

, het

erog

eneo

us, c

lose

d, n

on-r

eact

ing

syst

emin

a c

entri

fuga

l fie

ld.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

- 2.2.

It i

s not

an

over

stat

emen

t to

say

that

with

out s

tate

func

tions

ther

mod

ynam

ics w

ould

be

usel

ess.

Dis

cuss

this

asse

rtion

.

Ans

wer

to 2

.2.

If th

ere

wer

e no

stat

e fu

nctio

ns (l

ike

T, P

, V, c

ompo

sitio

n), i

.e.,

prop

ertie

s tha

t dep

end

only

upo

n th

e cu

rren

t con

ditio

n of

the

syst

em, a

nd n

ot o

n ho

w it

arr

ived

at t

hat c

ondi

tion)

then

the

beha

vior

of a

ll as

pect

s of m

atte

r wou

ld d

epen

d ex

plic

itly

upon

the

hist

ory

of th

e sy

stem

. Th

ere

wou

ld b

e no

var

iabl

es th

at, b

yth

emse

lves

, exp

licitl

y de

scrib

e th

e cu

rren

t con

ditio

n of

any

syst

em.

Thus

, eve

n th

e hi

stor

y ex

perie

nced

by

the

syst

em

2

coul

d no

t be

desc

ribed

in te

rms o

f som

e se

quen

ce o

f cha

nge

ofits

pro

perti

es.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

-

2.3.

Det

erm

ine

whi

ch o

f the

follo

win

g pr

oper

ties o

f ath

erm

odyn

amic

syst

em a

re e

xten

sive

pro

perti

es a

nd w

hich

are

inte

nsiv

e. a. T

he m

ass d

ensi

ty.

b. T

he m

olar

den

sity

.c.

The

num

ber o

f gra

m a

tom

s of

alu

min

um in

a c

hunk

of a

lum

ina.

d. T

he p

oten

tial e

nerg

y of

the

syst

em in

a g

ravi

tatio

nal

field

.e.

The

mol

ar c

once

ntra

tion

of N

aCl i

n a

salt

solu

tion.

f. T

he h

eat a

bsor

bed

by a

the

gas i

n a

cylin

der w

hen

itis

com

pres

sed.

Ans

wer

to 2

.3.

a. T

he m

ass d

ensi

ty is

the

ratio

of t

he m

ass o

f a sy

stem

to it

svo

lum

e; it

is in

tens

ive.

b. T

he m

olar

den

sity

is th

e ra

tio o

f the

num

ber o

f mol

es to

the

volu

me;

it is

inte

nsiv

e.

c. T

he n

umbe

r of g

ram

ato

ms i

s a p

rope

rty o

f the

syst

em a

s aw

hole

; it i

s an

exte

nsiv

e pr

oper

ty.

d. T

he p

oten

tial e

nerg

y of

the

syst

em is

a p

rope

rty o

f the

syst

em a

s a w

hole

; it i

s thu

s an

exte

nsiv

e pr

oper

ty.

e. T

he m

olar

con

cent

ratio

n is

the

ratio

of n

umbe

r of m

oles

toth

e vo

lum

e if

the

syst

em; i

t is a

n in

tens

ive

prop

erty

.

f. T

he h

eat a

bsor

bed

is a

pro

perty

of t

he sy

stem

as a

who

le; i

tis

an

exte

nsiv

e pr

oper

ty.

All

of th

e pr

oper

ties i

dent

ified

as i

nten

sive

als

o sh

are

the

char

acte

ristic

that

they

may

be

defin

ed a

t a p

oint

with

in th

esy

stem

, and

inde

ed m

ay v

ary

from

poi

nt to

poi

nt.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

-

2.4.

Why

is h

eat a

pro

cess

var

iabl

e?

Ans

wer

to 2

.4.

Hea

t is f

unda

men

tally

a fl

ow o

f ene

rgy.

Hea

t is

trans

ferr

ed b

etw

een

two

syst

ems,

or b

etw

een

parts

of t

he sa

me

syst

em;

this

rear

rang

emen

t of t

he d

istri

butio

n of

ene

rgy

isne

cess

arily

acc

ompa

nied

by

chan

ges i

n at

leas

t som

e of

the

prop

ertie

s of t

he sy

stem

s inv

olve

d. S

uch

a ch

ange

is b

yde

finiti

on a

pro

cess

.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

---

2.5.

Writ

e th

e to

tal d

iffer

entia

l of t

he fu

nctio

n

a. I

dent

ify th

e co

effic

ient

s of t

he th

ree

diff

eren

tials

in

3

this

exp

ress

ion

as a

ppro

pria

te p

artia

l der

ivat

ives

.b.

Sho

w th

at th

ree

Max

wel

l rel

atio

ns h

old

amon

g th

ese

coef

ficie

nts

Ans

wer

to 2

.5.

a.W

rite

the

tota

l diff

eren

tial o

f the

func

tion

z:

b.

Eval

uate

the

cros

s der

ivat

ives

:

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

-

4

2.6.

Des

crib

e w

hat t

he n

otio

n of

equ

ilibr

ium

mea

ns to

you

. Li

st a

s man

y at

tribu

tes a

s you

can

thin

k of

that

wou

ld b

eex

hibi

ted

by a

syst

em th

at h

as c

ome

to e

quili

briu

m.

Why

do

you

thin

k th

ese

char

acte

ristic

s of a

syst

em in

equ

ilibr

ium

are

impo

rtant

in th

erm

odyn

amic

s?

Ans

wer

to 2

.6.

Attr

ibut

es o

f equ

ilibr

ium

:

1. A

stat

e of

rest

: st

ate

of th

e sy

stem

doe

s not

cha

nge

with

tim

e.

2. A

stab

le st

ate:

if t

he st

ate

is d

ispl

aced

from

the

equi

libriu

m st

ate,

it w

ill re

turn

to it

.

3. A

stat

e of

inte

rnal

uni

form

ity;

(in th

e ab

senc

e of

exte

rnal

fiel

ds) g

radi

ents

of i

nten

sive

pro

perti

es v

anis

h.

The

equi

libriu

m st

ate

is th

e fin

al st

ate

of e

very

pro

cess

. Th

epr

imar

y go

al o

f the

rmod

ynam

ics i

s the

pre

dict

ion

of th

epr

oper

ties o

f the

fina

l equ

ilibr

ium

stat

e fo

r any

giv

en in

itial

cond

ition

of a

ny sy

stem

. "H

ow fa

r the

syst

em is

" fr

om th

eeq

uilib

rium

stat

e is

a m

easu

re o

f the

driv

ing

forc

e fo

r pro

cess

esch

angi

ng th

e sy

stem

tow

ard

equi

libriu

m, a

nd c

ontro

ls th

e ra

teof

app

roac

h to

the

final

stat

e of

rest

.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

-

Cha

pter

3. T

he L

aws o

f The

rmod

ynam

ics

5

Cha

pter

3. T

he L

aws o

f The

rmod

ynam

ics

3.1.

The

law

s of t

herm

odyn

amic

s are

"pe

rvas

ive"

. Ex

plai

n in

deta

il th

e m

eani

ng o

f thi

s im

porta

nt st

atem

ent.

Ans

wer

to 3

.1.

"Per

vasi

ve"

mea

ns th

at th

e la

ws a

pply

a. I

n ev

ery

syst

emb.

At e

very

inst

ant i

n tim

ec.

In

ever

y vo

lum

e el

emen

t

in w

hich

cha

nge

is o

ccur

ring.

Thi

s cha

ract

eris

tic e

mph

asiz

esth

e ge

nera

lity,

and

thus

the

pow

er, o

f the

law

s of

ther

mod

ynam

ics.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--

3.2.

Lis

t the

kin

ds o

f ene

rgy

conv

ersi

ons i

nvol

ved

inpr

opel

ling

an a

utom

obile

.

Ans

wer

to 3

.2.

Elec

trica

l ene

rgy

(the

spar

k) c

ombi

nes w

ith c

hem

ical

ene

rgy

(in th

e fu

el) t

o pr

oduc

e he

at a

nd m

echa

nica

l wor

k th

at d

rives

the

pist

ons i

n th

e en

gine

blo

ck; t

he m

echa

nica

l wor

k is

then

trans

mitt

ed th

roug

h th

e cr

anks

haft

and

trans

mis

sion

to th

e ax

lean

d th

e di

ffer

entia

l tha

t ulti

mat

ely

turn

s the

whe

els.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

3.3.

Lis

t the

kin

ds o

f ene

rgy

conv

ersi

ons i

nvol

ved

in o

pera

ting

a ha

nd c

alcu

lato

r.

Ans

wer

to 3

.3.

Che

mic

al e

nerg

y st

ored

in a

bat

tery

is c

onve

rted

to e

lect

rical

ener

gy th

at fl

ows t

hrou

gh th

e co

nnec

tors

and

inte

grat

edci

rcui

ts a

long

pat

hs d

eter

min

ed b

y m

echa

nica

l inp

ut th

roug

hth

e ke

ypad

. D

epen

ding

upo

n th

e na

ture

of t

he d

ispl

ay, t

hepa

ttern

of o

utpu

t ele

ctric

al e

nerg

y m

ay b

e us

ed to

alte

r the

stru

ctur

e of

mol

ecul

es in

a li

quid

cry

stal

or c

onve

rt to

ligh

ten

ergy

in a

n LE

D a

rray

.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

-

3.4.

Lis

t the

kin

ds o

f ene

rgy

conv

ersi

ons i

nvol

ved

in u

sing

your

arm

and

han

d to

turn

the

page

in th

is te

xt.

Ans

wer

to 3

.4.

Cha

pter

3. T

he L

aws o

f The

rmod

ynam

ics

6

Stor

ed c

hem

ical

ene

rgy

deriv

ed fr

om fo

od p

rodu

cts a

ndox

ygen

is c

onve

rted

to e

lect

rical

ene

rgy

whi

ch g

ener

ates

patte

rns i

n th

e br

ain

that

are

tran

smitt

ed th

roug

h th

e ne

ural

netw

ork

to m

uscl

es in

the

arm

and

han

d. T

hese

sign

als i

nduc

ech

emic

al a

nd e

lect

rical

cha

nges

in th

e re

quire

d m

uscl

esca

usin

g th

em to

con

tract

app

ropr

iate

ly;

this

con

tract

ion

isco

nver

ted

to th

e m

echa

nica

l wor

k in

volv

ed in

the

mot

ion

of th

ear

m a

nd h

and

as th

ey m

ove

thei

r wei

ght a

nd th

at o

f the

pap

erin

a g

ravi

tatio

nal f

ield

.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

---

3.5.

Sup

pose

the

conv

entio

n w

ere

adop

ted

that

def

ines

W a

ndW

' in

the

first

law

of t

herm

odyn

amic

s to

be th

e "w

ork

done

by

the

syst

em o

n th

e su

rrou

ndin

gs".

a. W

rite

the

first

law

with

this

alte

rnat

e co

nven

tion.

b. W

hy d

o th

e si

gns c

hang

e?

Ans

wer

to 3

.5.

a. b.

With

this

con

vent

ion

W is

def

ined

to b

e po

sitiv

e w

hen

it is

trans

mitt

ed fr

om th

e sy

stem

to th

e su

rrou

ndin

gs;

thus

if W

ispo

sitiv

e, th

e in

tern

al e

nerg

y of

the

syst

em d

ecre

ases

.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--

3.6.

Giv

e fiv

e ex

ampl

es o

f the

ope

ratio

n of

the

seco

nd la

w o

fth

erm

odyn

amic

s in

your

dai

ly e

xper

ienc

e; t

hey

mus

t be

diff

eren

t fro

m th

ose

give

n in

the

text

.

Ans

wer

to 3

.6.

1. T

he m

orni

ng c

offe

e co

ols w

ith ti

me.

2. S

ugar

dis

solv

es in

hot

cof

fee.

3. L

eft t

o its

elf,

a pe

ndul

um w

ill sl

ow to

a st

op.

4. O

rgan

ism

s die

.5.

An

expa

ndin

g ga

s coo

ls.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

---

3.7.

Bio

logi

cal s

yste

ms,

- org

anel

les,

cells

, org

ans,

plan

ts a

ndan

imal

s,- a

re h

ighl

y or

dere

d, y

et fo

rm sp

onta

neou

sly.

Doe

s the

form

atio

n an

d gr

owth

of b

iolo

gica

l sys

tem

s vio

late

the

seco

ndla

w o

f the

rmod

ynam

ics?

Exp

lain

you

r ans

wer

.

Ans

wer

to 3

.7.

No,

it d

oes n

ot v

iola

te th

e se

cond

law

of t

herm

odyn

amic

s. Th

eir f

orm

atio

n an

d gr

owth

are

acc

ompa

nied

by

chan

ges i

nth

eir s

urro

undi

ngs s

uch

that

the

tota

l cha

nge

in e

ntro

py o

f the

biol

ogic

al sy

stem

plu

s its

surr

ound

ings

is p

ositi

ve.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

3.8.

"Ir

reve

rsib

le"

is a

n aw

kwar

d ad

ject

ive.

Why

is th

is te

rmso

app

ropr

iate

in it

s app

licat

ion

to th

e de

scrip

tion

of p

roce

sses

Cha

pter

3. T

he L

aws o

f The

rmod

ynam

ics

7

in th

erm

odyn

amic

s? S

ugge

st tw

o or

thre

e al

tern

ate

wor

ds o

rph

rase

s tha

t mig

ht b

e us

ed to

repl

ace

"irr

ever

sibl

e" in

thes

eco

ntex

ts.

Ans

wer

to 3

.8.

Irre

vers

ible

mea

ns:

"Inc

apab

le o

f bei

ng re

vers

ed"

"The

reve

rse

proc

ess c

anno

t hap

pen"

"Per

man

ent c

hang

e pr

oces

s""I

rret

raca

ble"

The

wor

d is

app

ropr

iate

bec

ause

all

real

pro

cess

es a

reac

com

pani

ed b

y pe

rman

ent c

hang

e in

the

univ

erse

. By

defin

ition

, the

se p

erm

anen

t cha

nges

can

not b

e un

done

by

reve

rsin

g th

e in

fluen

ces d

rivin

g th

e pr

oces

s.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

3.9.

Con

trast

the

rela

tive

mag

nitu

des o

f the

ent

ropy

tran

sfer

vers

us e

ntro

py p

rodu

ctio

n in

the

follo

win

g pr

oces

ses:

a. A

ther

mal

ly in

sula

ted

cont

aine

r has

two

com

partm

ents

of e

qual

size

. In

itial

ly o

ne si

de is

fille

dw

ith a

gas

and

the

othe

r is e

vacu

ated

. A

val

ve is

open

ed a

nd th

e ga

s exp

ands

to fi

ll bo

th c

ompa

rtmen

ts.

b. A

gas

con

tain

ed in

a st

eel c

ylin

der i

s slo

wly

expa

nded

to tw

ice

its v

olum

e.

Ans

wer

to 3

.9.

a. I

n th

e th

erm

ally

insu

late

d ca

se th

ere

is n

o en

tropy

tran

sfer

; th

e to

tal e

ntro

py c

hang

e in

this

cas

e is

ent

ropy

pro

duct

ion.

b. S

low

exp

ansi

on m

inim

izes

dis

sipa

tion

effe

cts,

and

thus

isac

com

pani

ed b

y a

smal

l pro

duct

ion

of e

ntro

py;

mos

t of t

heen

tropy

cha

nge

in th

is c

ase

is e

ntro

py tr

ansf

er.

3.10

. C

onsi

der a

n is

olat

ed sy

stem

(no

heat

, mat

ter o

r wor

km

ay b

e ex

chan

ged

with

the

surr

ound

ings

) con

sist

ing

of th

ree

inte

rnal

com

partm

ents

A, B

and

C, o

f equ

al v

olum

es.

The

com

partm

ents

are

sepa

rate

d by

par

titio

ns; e

ach

parti

tion

has a

valv

e w

hich

may

be

open

ed re

mot

ely.

Ini

tially

the

cent

ral

volu

me

B is

fille

d w

ith a

gas

at 2

98K

(25o C

) and

the

oute

r tw

oar

e ev

acua

ted.

Con

side

r the

follo

win

g tw

o pr

oces

ses:

a. T

he v

alve

to th

e A

side

is o

pene

d, th

e ga

s exp

ands

free

ly in

to th

e co

mpa

rtmen

t A, a

nd th

e sy

stem

com

es to

equi

libriu

m.

Then

the

valv

e to

the

C si

de is

ope

ned,

and

the

syst

em a

gain

com

es to

equ

ilibr

ium

.b.

Bot

h va

lves

are

ope

ned

sim

ulta

neou

sly,

the

gas

expa

nds f

reel

y in

to b

oth

com

partm

ents

, and

the

syst

emco

mes

to it

s equ

ilibr

ium

.

Whi

ch o

f the

se p

roce

sses

pro

duce

s mor

e en

tropy

?

Ans

wer

to 3

.10.

The

initi

al st

ates

are

the

sam

e fo

r the

se p

roce

sses

; th

e fin

alst

ates

are

als

o th

e sa

me.

Sin

ce e

ntro

py is

a st

ate

func

tion,

the

entro

py c

hang

e fo

r bot

h pr

oces

ses m

ust b

e th

e sa

me.

Cha

pter

3. T

he L

aws o

f The

rmod

ynam

ics

8

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

---

3.11

. It w

ill b

e sh

own

in c

hapt

er 4

that

the

chan

ge in

ent

ropy

)S

asso

ciat

ed w

ith p

roce

ss a

in p

robl

em 3

.6 is

4.6

0 (J

/mol

-K),

and

that

the

initi

al a

nd fi

nal s

tate

s will

be

at th

e sa

me

tem

pera

ture

. A

pplic

atio

n of

equ

atio

n (3

.10)

sugg

ests

that

the

heat

abs

orbe

d by

the

syst

em d

urin

g th

is p

roce

ss is

Yet

the

desc

riptio

n of

the

syst

em sa

ys it

is is

olat

ed fr

om it

ssu

rrou

ndin

gs so

that

Q =

0.

Expl

ain

this

app

aren

tco

ntra

dict

ion.

Ans

wer

to 3

.11.

Equa

tion

(3.1

0) a

pplie

s onl

y to

reve

rsib

le p

roce

sses

. It

ther

efor

e do

es n

ot a

pply

to th

e pr

oces

ses d

escr

ibed

in P

robl

em3.

10.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

3.12

. Giv

e th

ree

exam

ples

of p

roce

sses

that

are

impo

rtant

inm

ater

ials

scie

nce

that

are

ther

mod

ynam

ical

ly "

irrev

ersi

ble"

. Sp

ecul

ate

brie

fly a

bout

the

natu

re o

f the

dis

sipa

tions

in th

ese

proc

esse

s tha

t con

tribu

te to

the

prod

uctio

n of

ent

ropy

.

Ans

wer

3.1

2

a. H

eat f

low

is c

ruci

al in

man

y in

dust

rial r

efin

ing

oper

atio

ns in

whi

ch c

hem

ical

reac

tions

pro

duce

larg

e qu

antit

ies o

f hea

t. T

hedi

sper

sion

of h

eat t

hrou

gh th

e sy

stem

and

surr

ound

ings

is a

diss

ipat

ion

that

can

not b

e re

cove

red.

b. M

ost m

icro

stru

ctur

al c

hang

es in

mat

eria

ls in

volv

e a

redi

strib

utio

n of

the

chem

ical

com

pone

nts c

alle

d di

ffus

ion.

Li

ke h

eat f

low

, the

rear

rang

emen

t of t

he sp

atia

l dis

tribu

tion

ofth

e at

oms t

hrou

gh th

e sy

stem

is a

dis

sipa

tion

that

can

not b

ere

cove

red.

c. I

ons i

mpl

ante

d in

the

fabr

icat

ion

of d

opan

t lay

ers i

n th

infil

ms i

n in

tegr

ated

circ

uits

are

not

rem

oved

by

sim

ply

reve

rsin

g th

e el

ectri

cal f

ield

. R

emov

al o

f the

ions

cou

ld o

nly

be a

ccom

plis

hed

by e

vapo

ratin

g th

e w

hole

film

and

rede

posi

ting

it.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

---

3.13

. The

not

ion

of a

"re

vers

ible

" pr

oces

s is a

fict

ion

in th

e re

alw

orld

. W

hat m

akes

this

con

cept

, whi

ch a

t firs

t gla

nce

wou

ldap

pear

to b

e on

ly o

f aca

dem

ic in

tere

st, s

o us

eful

in a

pply

ing

ther

mod

ynam

ics t

o re

al w

orld

"irr

ever

sibl

e" p

roce

sses

?

Ans

wer

to 3

.13.

If th

e pr

oper

ty c

hang

es th

at a

re o

f int

eres

t in

a re

al ir

reve

rsib

lepr

oces

s are

stat

e fu

nctio

ns, t

hen

thei

r cha

nges

will

be

the

sam

efo

r eve

ry p

roce

ss th

at c

onne

cts t

he in

itial

and

fina

l sta

tes o

f the

proc

ess.

In p

artic

ular

, the

se c

hang

es w

ill b

e th

e sa

me

as fo

rso

me

reve

rsib

le p

roce

ss th

at ta

kes t

he sy

stem

bet

wee

n th

ese

Cha

pter

3. T

he L

aws o

f The

rmod

ynam

ics

9

two

stat

es.

Cal

cula

tion

of c

hang

es fo

r a re

vers

ible

pro

cess

isve

ry m

uch

sim

pler

than

for i

rrev

ersi

ble

proc

esse

s bec

ause

inte

rnal

inte

nsiv

e pr

oper

ties l

ike

tem

pera

ture

and

pre

ssur

e ar

eun

iform

in th

e sy

stem

dur

ing

the

chan

ge. T

hus c

alcu

latio

ns o

fch

ange

s in

stat

e fu

nctio

ns fo

r irr

ever

sibl

e pr

oces

ses a

re m

ade

acce

ssib

le th

roug

h th

e us

eful

fict

ion

of th

e re

vers

ible

proc

esse

s.

In a

dditi

on,

for r

ever

sibl

e pr

oces

ses g

ener

al re

latio

nshi

ps a

reav

aila

ble

for c

ompu

ting

W a

nd Q

from

stat

e fu

nctio

nin

form

atio

n by

inte

grat

ing

alon

g th

e si

mpl

est p

ath

that

con

nect

s the

initi

al a

nd fi

nal s

tate

s.Th

ese

resu

lts m

ay b

e us

ed to

est

imat

e pr

oper

ties o

f rea

lev

olvi

ng sy

stem

s tha

t are

car

ried

out s

low

ly, n

ear e

quili

briu

m.

They

als

o pr

ovid

e es

timat

es o

f the

max

im h

eat a

bsor

bed

orw

ork

that

cou

ld b

e do

ne o

n th

e sy

stem

.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

---

3.14

. The

com

bine

d st

atem

ent o

f the

firs

t and

seco

nd la

ws o

fth

erm

odyn

amic

s, eq

uatio

n (3

.15)

, ev

alua

tes t

he h

eat a

bsor

bed

and

mec

hani

cal w

ork

done

on

a sy

stem

with

rela

tions

hips

that

are

only

val

id fo

r rev

ersi

ble

proc

esse

s. S

ince

reve

rsib

lepr

oces

ses d

o no

t occ

ur in

the

real

wor

ld, h

ow is

it p

ossi

ble

for

the

com

bine

d st

atem

ent t

o pl

ay a

n im

porta

nt ro

le in

the

anal

ysis

of p

ract

ical

"irr

ever

sibl

e" p

roce

sses

enc

ount

ered

inna

ture

and

in te

chno

logy

?

Ans

wer

to 3

.14.

The

com

bine

d st

atem

ent i

s use

d to

eva

luat

e dU

, whi

ch is

ast

ate

func

tion.

Thu

s, th

e co

mbi

ned

stat

emen

t may

be

used

toca

lcul

ate

the

chan

ge in

inte

rnal

ene

rgy

for a

ny ir

reve

rsib

lepr

oces

s bec

ause

)U

is th

e sa

me

as fo

r a re

vers

ible

pro

cess

join

ing

the

sam

e in

itial

and

fina

l sta

tes.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

---

3.15

. D

escr

ibe

the

kind

s of e

xper

imen

tal o

bser

vatio

ns th

atha

ve b

een

invo

ked

to su

ppor

t the

hyp

othe

sis t

hat t

he e

ntro

py o

fal

l sub

stan

ces i

s the

sam

e at

abs

olut

e ze

ro.

Ans

wer

to 3

.15.

Entro

py c

hang

es a

ssoc

iate

d w

ith h

eatin

g or

coo

ling

the

pure

elem

ents

and

com

poun

ds m

ay b

e co

mpu

ted

from

hea

t cap

acity

mea

sure

men

ts a

s a fu

nctio

n of

tem

pera

ture

for t

hese

subs

tanc

es.

Entro

py c

hang

es fo

r rea

ctio

ns b

etw

een

thes

esu

bsta

nces

may

be

eval

uate

d fr

om h

eats

of r

eact

ion

orm

easu

rem

ents

equ

ilibr

ium

com

posi

tions

.

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

3.16

. U

se th

e fo

llow

ing

valu

es o

f abs

olut

e en

tropi

es o

fel

emen

ts a

nd c

ompo

unds

at 2

98K

to c

ompu

te th

e st

anda

rden

tropy

cha

nges

ass

ocia

ted

with

as m

any

chem

ical

reac

tions

as

you

can

gene

rate

from

this

list

.

Cha

pter

3. T

he L

aws o

f The

rmod

ynam

ics

10

Al

2

8.3

CO

197.

9

C(g

r)

5.

69C

O2

213.

64

Si

1

8.83

Al 2O

3 5

1.1

O2

20

5.03

SiC

16.

54

SiO

2

41.

5

Ans

wer

to 3

.16.

For a

ny re

actio

n of

the

form

whe

re l,

m, r

, s,..

. are

stoi

chio

met

ric c

oeff

icie

nts f

or th

eco

mpo

nent

s L, M

, R, S

,...,

the

corr

espo

ndin

g ch

ange

in e

ntro

pyfo

r the

tran

sfor

mat

ion

from

pur

e re

acta

nts t

o pu

re p

rodu

cts a

t29

8 K

(the

"st

anda

rd e

ntro

py c

hang

e") i

s giv

en b

y

The

follo

win

g lis

t of r

eact

ions

can

be

gene

rate

d am

ong

thes

eco

mpo

nent

s is n

ot e

xhau

stiv

e.

REA

CTI

ON

)So (J

/mol

K)

Form

atio

n R

eact

ions

:

Line

ar C

ombi

natio

ns:

A la

rge

num

ber o

f lin

ear c

ombi

natio

ns o

f the

form

atio

nre

actio

ns m

ay b

e co

nstru

cted

, inc

ludi

ng, e

.g.,