Modern Approach to Chemical Calculations R C Mukherjee Ramendra Chandra Mukerjee IIT JEE Physical Chemistry Bharati Bhawan not Mukherji Mukerji

923 Pages·2019·5.725 MB·English

by  R C Mukherjee Ramendra Chandra Mukerjee Mukherji Mukerji

MODERN APPROACH
TO
Chemical Calculations
AN INTRODUCTION TO THE MOLE CONCEPT
Ramendra C Mukerjee, MSc,PhD
Department of Chemistry
Ewing Christian College, Allahabad
(An Autonomous College of Allahabad University)
P R E F A C E
The book continues the tradition of providing a firm foundation in chemical
calculations. I have included quite a good number of problems with hints
wherever necessary. The challenge to me has always been to present a solid
understanding of the basic facts and principles of chemistry. I am fully
confidentthatthepresentbookwillhelpthestudentspreparefortheJEEand
other engineering and medical entrance examinations.
Thedesignofquestionpapers,particularlyoftheJEE,changesfromtime
totime.Rememberthatchemistryhasnotchanged.Ifeelstronglythatifyou
understand the subject well, you can solve any question in any form. I have
also noticed that questions are now being asked from all chapters including
the mole concept, stoichiometric calculations, etc. Previously, it used to be
selective. Another important fact is that the questions are sometimes too
difficult for students of +2 level. In that case you may consult my book
‘ModernApproachtoPhysicalChemistry,volumesIandII’foranadvanced
knowledgeofphysicalchemistry.Basically,readeverychapterverycarefully
tillyouhaveavividpictureofthesubjectinyourmind.Finally,followSwami
Vivekananda’s saying,
Arise, Awake and Stop Not
till the goal is achieved.
RamendraCMukerjee
PREFACE TO THE EIGHTH EDITION
Itakeimmensepleasureinpresentingyoutheeightheditionofthisbook.On
thebasisofhelpfulsuggestionsgivenbylearnedteachersandstudentsfrom
alloverthecountry,andalsoinviewoftherecentchangesinthesyllabusand
in the examination pattern of IIT-JEE, all the chapters have been critically
reviewed. Some changes in the presentation of the text and the necessary
additions, both in the text and in the problems, have been carried out. The
revision chapters 21 and 22 have been updated by including the questions
askedinIIT-JEEoftherecentpastyears.Mygoalinthisrevisionistoprovide
students with the best possible tool for learning numerical chemistry, by
(iii)
incorporating and amplifying features that enhance their understanding of
concepts. Here are some of the new features:
The presentation of thermodynamics has been reorganized. The
consistentpresentationhelpstoconsolidatetheconceptsofthermodynamics.
As the central concepts of chemical change are best understood in the
sequenceofchemicalthermodynamics(Istheforwardorthereversereaction
favoured?),chemicalthermodynamicsisnowplacedasChapter14,followed
by chemical equilibrium (Chapter 15), ionic equilibrium (Chapter 16—How
farthereactionwouldgo?)andthenbychemicalkinetics(Chapter17—How
fast the reaction would go?).
Though the oxidation and reduction processes have been discussed in
chapters6,7and18,anewchapter(19)ontheconceptsofoxidationnumber
anditsapplicationtobalanceredoxreactionshasbeenadded.Chapter20on
solidstatehasbeenextendedbyincludingtheliquidstate.Chapters21and22
contain only problems for the purpose of revision.
Manyofmycolleagueshavehelpedmewritethisbook,toallofwhomI
am sincerely thankful. I especially thank Mr D Kumar, former Head,
Chemistry Department of our college, with whom I have discussed many
problems, and Dr G K Verma, C M P Degree College, for offering me many
useful suggestions. I am greatly indebted to Prof. S S Shukla, Lamar
University,Texas,USA,forgoingthroughthemanuscriptofthefirstedition
and making invaluable suggestions. I wish to express my appreciation to all
the students and teachers who have been kind enough to write letters with
helpful suggestions for the improvement of the book. Special thanks are due
to my own students for pointing out a number of errors. Finally, I thank all
the members of the Bharati Bhawan family who were involved in the
production of this edition.
I believe this edition will continue to prove useful to the students and
interesting to the teachers.
132 B/2A, Alopibagh RamendraCMukerjee
Allahabad 211 006
(iv)
A Message
Dear Students,
This is a textbook on chemical calculations primarily intended for
students who are preparing for the entrance tests of IIT and other
engineering colleges. This text is equally useful to the students of
Intermediate(+2) and BSc classes of Indian universities.
Chemistry is just one of the subjects you have to study and, therefore,
you have limited time for each subject. Keeping in mind your limited
time and requirements, I have tried my best to write this book in such a
way that it fulfils your requirements. The special features of the book are:
1. This book has been written in the language of the mole, as the concept
of mole is a basic tool in understanding chemistry. Try to have fun with
the mole; I did.
2. Sufficient fundamental principles have been provided before introducing
problems. These principles, in the form of rules or equations, have been
referred to throughout the book while solving problems. This will help
you in following each step of the solutions of these problems.
3. A wide variety of problems have been selected; at the same time
repetitions of similar types of problems have been avoided. This allowed
me to give maximum coverage in minimum space.
4. Mixed system of units including SI units have been used in this text in
accordance with the latest trend of the entrance tests of IIT and most of
the other engineering colleges. Moreover, a selected list of basic and
derived SI units and conversions of selected nonsystem units to SI units
have been provided at the beginning of the book to help you solve
problems using different systems of units.
Finally, I would like to suggest two important points so that you can take
the maximum advantage from this book.
 Read Chapter 1 and Chapter 14 very carefully as both these chapters
have wide applications in other chapters.
 Do not jump directly to solving the problems until you have
thoroughly gone through the text provided at the beginning of each
chapter.
Ramendra C Mukerjee
(v)

Selected SI Units (Systeme International d’ Unites)
Unit
Quantity
Name Symbol
Basic Units:
Length metre m
Mass kilogram kg
Time second s
Electric current ampere A
Temperature kelvin K
Luminous intensity candela cd
Amount of substance mole mol
Derived Units:
Volume cubic metre m3
Density kilogram per kg/m3
cubic metre
Force newton N (kgm/s2)
Pressure pascal Pa (N/m2)
Energy, work, heat joule J (Nm)
Power watt W (J/s)
Quantity of electricity coulomb C (As)
Electric voltage, volt V (W/A)
electrical
potential, emf
Resistance ohm  (V/A)
Conductance siemens  1
Frequency hertz Hz s  1
(cid:3) (cid:137)
(vii)
Conversion of Selected Nonsystem Units to SI Units
Quantity Unit Conversion factor to SI
centimetre 1  10 2 m
micrometre m 1  10 6 m

Length nanometre nm 1  10 9 m
angstrom Å 1  10 10 m

inch 254  10 2 m
Mass gram 1  10 3 kg
Volume litre 1  10 3 m3  dm3
bar 105 Pa
atmosphere atm 101325  105 Pa
Pressure 
millimetre of Hg 133322 Pa

or torr
electronvolt eV 160219  10 19 J
Energy, work, amount calorie cal 41868 J

of heat kilocalorie kcal 41868 J

erg 10 7 J
(cid:137)
(viii)
Values of Selected Fundamental Physical Constants
Quantity Symbol Value
Planck constant h  66262  10 27 erg  s
 66262  10 34 J  s SI
Avogadro number N  6022  1023 mol 1 SI
(Avogadro constant)
Boltzmann constant k  13807  10 16 erg deg 1
molecule 1
 13807  10 23 JK 1 SI
Gas constant R  8314  10 7 erg deg 1 mole 1
 8314 JK 1 mol 1 SI
 00821 L  atm deg 1 mole 1
 1987 cal deg 1 mole 1
Molar volume of gas at V  22414 L mole 1
NTP  22414  10 3 m3 mole 1 SI
Velocity of light c  2998  1010 cm s 1
 2998  108 m s 1 SI
Electron mass m  9109  10 28 g
e
 9109  10 31 kg SI
Electron charge e  4803  10 10 esu
 1602  10 19 coulomb SI
Faraday constant F  96485 coulomb eq 1
 96484 coulomb mol 1 SI
Acceleration due to gravity g  980665 cm s 2
 980665 m s 2 SI
Atomic mass unit amu  166  10  27 kg SI
(cid:137)
(ix)
A Few Abbreviations Used in This Book
Principle of Atom Conservation POAC
Weight Wt.
Atomic weight At. wt.
Molecular weight Mol. wt.
Equivalent weight Eq. wt.
Gram Equivalent or Equivalent Eq.
Equation Eqn.
Equilibrium Eqb.
Milli-equivalent m.e.
Molar M
Molal m
Normal N
Demal D
(cid:137)
(x)