Preview principles of physical chemistry by dr mahbubul haque, dr mohammad yousuf ali mollah

Preview Principles of physical chemistry by Dr. Mahbubul Haque, Dr. Mohammad Yousuf Ali Mollah Preview Principles of physical chemistry by Dr. Mahbubul Haque, Dr. Mohammad Yousuf Ali Mollah Preview Principles of physical chemistry by Dr. Mahbubul Haque, Dr. Mohammad Yousuf Ali Mollah Preview Principles of physical chemistry by Dr. Mahbubul Haque, Dr. Mohammad Yousuf Ali Mollah Preview Principles of physical chemistry by Dr. Mahbubul Haque, Dr. Mohammad Yousuf Ali Mollah

Huque and Nawab Principles of Physical Chemistry Fully Revised by Dr Muhammad Mahbubul Huque Dr Muhammad Yousuf All Mollah / Ị P Brothers' Publications ■' r Huque and Nawab Principles of Physical Chemistry I Revised by jumad Mahbubul Huque Mohammad Yousuf A Mollah Brothers' Publication / , Rafme Plaza Mirpur Road, D haka-1205 January, 2009 P u b lish e d by B ro th ers' Publication 3/5, Rafine Pia2a M irpur Road, D haka-1205 First Edition : 1968 Second Edition : 1971 Fully Revised Edition : 2009 \ Fully Revised Edition-20\ (All rights reserved, no part of this publication can be reproduced in any farm w ithout the prior perm ission o f the authors.] C o m p o sed by Alka Com puter Banglabazar, D h ak a-1100 Muhammad Mahbubul Hu que M.Sc (Dhaka), Ph D (McGill, Canada) Former Professor Department o f Chemistry Dhaka University, Dhaka and , ■ Founding Chairman Department o f Chemistry Jahangimagai University Savar, Dhaka Mohammad Yousuf All Moliah M.Sc (Dhaka), Ph D (Macquarie, Australia) Professor Department o f Chemistry Dhaka University, Dhaka cr" AVAILABELE AT: BROTHER’S PUBLICATIONS 3/5B RAFIN PLAZA MOBILE - 01674175433 R A IN B O W B O O K M A L L 125, Isla m ia M a rk e t, N iik h e t Y O U SU F B O O K STA LL Isla m ia M a rk e t, N ilk h e t BOOKS PA R A D ISE lslam ia M arket, N ilkhet M EM ORY BOOKS Isla m ia M a rk e t, N ilk h e t K A CH U Y A BO O K C EN TRE Isiam ia M arket, N iikhet FARHAN BOOK CENTRE D ECEN T BOOK H OUSE Isia m ia M a rk e t, N ilk h e t STUD EN TS BOOK Ista m ia M a rk e t, N ilk h e t N O R TH STAR Isla m ia M a rk e t, N ilk h e t RELAX BOOK Isla m ia M a rk e t, N ilk liet K A M AL BOOK H OUSE Khulna M ALANCHA LIBRARY Sylhet B O O K S G A IID E N C h itta g o n g O M A R DOI G H O R C h itta g o n g B O IN K E T O N C h itta g o n g BOI GH AR Rajshahi N E W N A T IO N Sylhet POPY BOOKS S h y lh e t G E N U IN E L IB R A R Y C h itta g o n g SOBUJ L IR A R Y R a jsh ah i P R IM E B O O K R a jsh ah i A L I GOR Rajshahi Istamia Market, Milkhet H e lp line BROTHER’S PUBLICATIONS 01819440121,0] 720-579009, 01199-198703 0X711662823 Dedicated to the memory of Late Professor M Ali Nawab Professor M A Nawab was (he senior author o f the First Edition o f the book He was Professor of the Department o f Chemistry o f Dhaka University Late Professor Nciiuab xoas the Chairman o f the Department o f Chemistry of Dhaka University during 1973-Ĩ976 Professor Nawab expired on 23 April 1993 PREFACE TO THE REVISED EDITION The first edition of 'Principles o f Physical C hem istry' was published in 196S and the third edition cam e in 1974 The authors did not make attem pts to bring out further editions of the book as at th.ii time science texl books written in Bengali were preferred by the students W e had forgotten aboui ihe book Professor M A Nawab, [he senior author expired in 1993 Then about three years back a former student o f mine who was doing undergraduate studies in Pharmacy in a Private University in Dhaka showed me a photocopy of ihe original third edition o f the book which was being used as a text book This was described as a ‘fully revised edition’, A survey revealed that a large num ber o f students in different universities and colleges in Banzladesh were using this Tully revised edition’ as a text book o f Physical Chemistry As mentioned this was not a Revised Edition as the authors did not m ake any revision after Ihe third edition Professor M Y ousuf A M ollah Professor o f Physical Chem istry at the Dhaka U niversity, persuaded me to prepare a revised edition I agreed on condition that he will be a co-author The book on Physical Chem istry being presented with !he same title as !he original one is (he result o f joint efforts o f Prof M Y ousuf A Mollah and me We traced the printing house which had been marketing ibe photocopies as 'fully revised edition’ They apologized for their action and agreed to publish the edition we have prepared This is a Fully Revised Edition with m ajor changes W hite rewriting this book we focused on !he syllabii of undergraduate courses o r Physical C hem istry o f Public, Private U niversities and U niversity Colieges in Bangladesh The students o f Pharm acy, Biochemistry and Engineering will also be benefited from this book All through the book SI units have been used Many chapters have been rewritten with additional materials A num ber o f chapters have been divided into sm aller chapters for the convenience o f the Students: For exam ple Therm odynam ics has been presented in three chapters with titles: Therm odynam ics I: the First Law, Therm ochem istry, Therm odynam ics II: [he Second and the Third Law, The chapter on Solution has been divided into Solution and D ilute Solution E lectrochem istry has been divided into two chapters: Electrolytic Conduction and Electrolysis, Elecirochemical cells T he chapter on Reaction Kinetics has been presented com pletely in a new format Acids and Bases have been presented as a separaie chapter Solubility and Solubility Product form a new chapter As the m aterial presented in the chapter on Surface Chem istry and Colloids in the third edition is considerable, this has been split into two chapters: Surface Chem istry and Colloidal Slate In many chapters topics have been rewritten with [he inclusion of new materials and presented in a belter w ay: B rief discussion o f mass spectra, IR and N.M.R spectra and their applications are included in ihc chapter on Physical Properties and M olecular Structure End o f Chapter Q uestions and Problem s have been revised, many new questions arid problem s with answers have been incorporated The format of the book has also been changed W e hope that the Revised Edition o f the book with its new look will receive the same acceptance by the students and teachers as the earlier editions Printing o f this book has been an arduous task The publishers are not well acquainted with printing a book on science with a lot o f Figures and formulae They have, however, made great efforts to keep the book free of printing m istakes W e thank the publishers fur [heir valiant efforts In spite o f their best intentions you will find som e errors W e hope to eliminate these in the future edition January, 2009 M M Huque PREFACE TO THE SECOND EDITION We are gratified to see that the first edition of the book has been well accepied by the students and teachers in spite o f the numerous printing errors In the preparation o f second edition attem pt has been m ade lo increase the clarity of the presentation at several places The num ber o f numerical exam ples at the end of [he chapters has been considerably increased Apart from these changes little has been altered in (he arrangem ent o f the material and the get up W e have also tried hard to keep the printing errors at the minimum We are indebted to many o f our colleagues in the universities and colleges who have kindly sent their criticism s and pointed out the shortcom ings of the first edition These have been o f great help in making im provem ent in the clarity of representation We are sorry, we could not make ihe book com pletely free of mistakes in spite o f our best wishes January, 1971 Dhdka M M H uque M A N aw ab " > (viii) PR EFA CE TO THE FIRST EDITION Printing o f an object by a hundred painters, or writing o f a hundred poetrv on tile same subject need no explanation, but writing on a book on a subject like Physical Chemistry calls for an explanation specially w hen excellent books in English are available D ufing the last many years of teaching Physical Chemisiry 10 the undergraduate students, we have always felt the necessity o f explaining the fundamental conccpls W e believe that once the basic principles have been understood by the students, more than halt the battle IS won In this respect, there is a need for a book on Physical Chem istry for our students whose background is different from those for whom the available books are meant Many o f these books cover fields wider and deeper thjn what is needed for our undergraduates at the B Sc (Pass) level We, therefore, felt the necessity o f w riting a book on Physical Chem istry that would fully meet (he requirements o f the B Sc (Pass) students and the same tim e help in building a sound background for the Honours students, We always tried, while writing the book, to explain the basic principles as clearly and elaborately as possible It is uptu the teachers who leach the subject and the students who would read to ju d g e whether our aims have been ÍU[filled In the book most portions deal with the kinetic theory, Ihermodynam ics and chemical kinetics We have used i.ome final results and equations o f Q uantum Chem istry and did not go anywhere beyond it because we thought that o m n iu m Chem istry and Statistical M echanics should be treated at a higher level Although the approach - has been basically classical attempts have been made to acquaint ihe students with therm odynam ic approach, tn many placcs both kinetic and therm odynam ic treatment have been used to show that identical results can be obtained Only the methodology and physical concept are different Q uanlum mechanics! approach has been kepi to minimum, only flashes appear here and there In several places we have gone a little beyond than what is expected to form the syllabus o f Pakistani Universities The idea is to point to the fact that improvements need be made as is constantly being done in w estern countries This is further meani to provide the mental food for [he more serious and above average students The average students may leave out the.sc portions on advanced treatment Contrary to com m on practice we have not included a chapter on atomic structure and radioactivity These two topics generally form a part o f Inorganic Chemistry syllabus in our country and excellent treatment is available in text books of Inorganic Chemistry W e therefore, thought it wise to leave oul the branches from the present volume This has considerably reduced (he size of the book W c express our thanks to a num ber o f our colleagues who always inspired us during the writing o f (he book Thanks are specially due to Prof M H Khundkar Head o f the D epartm ent o f Chemistry, University o f D haka, for his encouragem ent at various stages Mr A J M ahm ood Senior Lecturer in Chemistry U niversity o f D haka, deserves special thanks for kindly going through a large portion o f the manuscript and m aking valuable suggestions Thanks are also due to Mr A N, M Akhter, a student o f the Dhaka College, for draw ing a number of original sketches and helping in making the design o f the dust cover We are indebted to Mr M esbahul Haque for preparing the index We must also thank Mr Sycd Md Fazlul Huq of the S tudents' Publications for taking the task of publishing the book Mr A K M Raja Meah deserves special m ention Cor his untiring efforts and hard work in the printing o f the book G ood printing is a challenging task and in spite o f our best efforts som e mistakes are still there We apologise for this and hope to im prove in the next edition We shall appreciate receiving com m ents from those w ho use the book, so that im provem ents can be made in future D epartm ent o f Chemistry U niversity of Dhaka Ju n u jfy 1968 M M Huque M A Nawab (ix) CONTENTS S T A T E O F A G G R E G A T IO N O F M A T T E R IN T E R M O L E C U L A R F O R C E S 1.1 Matter: States o f Aggregation 1.2 lnterm olecular Forces 1.3 Hydrogen bondi ' I _ 11 QUESTIONS AND PROBLEM S 12-76 T H E G A SE O U S S T A T E 2.1 Ideal G ases: T he G as Law s 12 12 2.2 B oyle's Law C h a rle s’ Law o r G ay-L ussac's Law 2.4 The A bsolute Z ero o f T em p eratu re 2.5 A vogadro's L aw 2.6 The Ideal Gas E quation 2.7 The Significance o f R 2.8 29 Page -1 15' ‘ 17 17 ■ 18 18 19 T he N um erical V alue o f R T he Use o f the G as E quation in C a lcu latio n s In v o lv in g G ases 20 D iffusion and E ffusion: G raham ’s Law ot D iffusion 21 11 E quation o f S tale o f a G as M ixture: D alto n 's Law OÍ P a rtia l P re ssu re 22 2.12 T he K inetic T heory o f G ases 2.13 R o oi-m ean-square (r.m s.) V elocity 2.14 D erivation o f the K inetic E quation 2.15 D eduction o f the G as Law s from the Kinetic E quation 2.16 M olecular V elocities 2.17 D istribution o f V elocities 2.18 Average Velocity, r.m.s Velocity and Most Probable Velocity 2.19 Mean Free Path 2.20 V iscosity of G ases 2.21 M o lecular D iam eter 2-22 Frequency o f C ollisions o f Gas Molecules 2.23 N um ber o f M olecules Striking a S urface 2.24 A vogadro N um ber 25 The Kinetic T heory - a review: Brow nian M ovem ent f 26 r2 B ehaviour o f R eal G ases: T he A m agat s C u rv es Modification of the Ideal Gas Equation: van der W aals' Equation o f State -’8 Significance and L im itations o f van der W aals E quation 2.29 O ther Equations o f S tate 2.30 Change of State: G as-Liquid Transition 2.31 A ndrew s’ E xperim ents with C O ; 10 24 25 25 27 29 30 31 32 33 33 34 35 > 35 36 37 38 41 43 43 44 The Solid State 105 which the arm o f the rotating table moves T he radiation reflected from the crystal is led into a detecting device w hich is usually an ionization cham ber The cu en t produced by the ionization o f an easily ionizable gas, such as m ethyl brom ide, in this cham ber is m easured by m eans o f an electrom eter T he current is a m easure o f the intensity o f radiation T he ionization cham ber may also be rotated around the sam e axis as the crystal This cham ber is rotated at tw ice the rate o f the rotation o f the table carrying the crystal T he intensity of ionization produced at different angles are m easured by the electrom eter and these are plotted against 20 Figure 4.13 X-ray diffraction apparatus T here w ere m axim a in the graphs and these m ust co in cid e w ith the an g les for w hich the B ragg equation, nX = 2d sinB, holds T h e m ax im a c o e sp o n d in g to n = 1, 2, 3— are know n as first-order, second-order, th ird -o rd er etc reflectio n s T he curves obtained for sodium chloride and potassium chloride cry stals are sh o w n in F igure 4.14, In order to determine d, the spacing of the planes of atoms or ions in the crystal, from X-ray measurements the wavelength of the incident X-ray beam must be known, N o w a ­ days X-ray tubes are available which give a monochromatic X-ray beam of kno\yn wavelength X-ray tubes with a copper target which gives off a beam with wavelength equal to 15.40 nm are in common use • KCI (200) J Ì (220) 1 0° 11y r\ A I ( 111) NaCl A 20° A 30° 40 0° Ầ\ 10° A 20° 0° 0a Figure 4.14 Graph of intensity against 20 for NaCl and KCỈ 4.7 Cubic Lattices In the cubic lattice system the three different space lattices are called the simple cubic, the face-centred cubic and the body-centred cubic lattices In the simple cubic lattice the structural units are at each com er of the unit cube In the face-centered lattice 106 Principles of Physical Chemistry there is one unit at the centre of each face, in addition to those at the com ers Bodycentered lattice is distinguished by having one unit at the centre and one at each com er of the unit cube These are schematically shown in Figure 4.9 The three types of reflecting planes in each of the three lattices are shown in Figure 4.15 din= /3a dj!0= Ì2a dioo = a (a) ÍM - M