THE WORLD OF PHYSICAL CHEMISTRY / KEITH }. LAIDLER Digitized by the Internet Archive in 2019 with funding from Kahle/Austin Foundation ( https://archive.org/details/worldofphysicalcOOOOIaid The World of Physical Chemistry The Hon. Robert Boyle (1627-1691) * The World of Physical Chemistry KEITH J. LAIDLER Professor Emeritus of Chemistry, The University of Ottawa Ontario, Canada Oxford • New York • Toronto OXFORD UNIVERSITY PRESS tstmm c^teilxyrouQh. Qnt Oxford University Press, Walton Street, Oxford 0X2 6DP Oxford New York Athens Auckland Bangkok Bombay Calcutta Cape Town Dar es Salaam Delhi Florence Hong Kong Istanbul Karachi Kuala Lumpur Madras Madrid Melbourne Mexico City Nairobi Paris Singapore Taipei Tokyo Toronto and associated companies in Berlin Ibadan Oxford is a trade mark of Oxford University Press Published in the United States by Oxford University Press Inc., New York © Keith f. Laidler, 1993 First published 1993 First published in paperback (with corrections) 1995 Reprinted 1995 (with corrections) All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press. Within the UK, exceptions are allowed in respect of any fair dealing for the purpose of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act, 1988, or in the case of reprographic reproduction in accordance with the terms of licences issued by the Copyright Licensing Agency. Enquiries concerning reproduction outside those terms and in other countries should be sent to the Rights Department, Oxford University Press, at the address above. This book is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, re-sold, hired out, or otherwise circulated without the publisher’s prior consent in any form of binding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser. A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data Laidler, Keith fames, 1916— The world of physical chemistry / Keith f. Laidler.—1st ed. Includes bibliographical references (p. ) and index. 1. Chemistry, Physical and theoretical—History. I. Title. QD452.L35 1993 541.3—dc20 92-41635 ISBN 0 19 855597 0 (Hbk) ISBNO 19 855919 4 (Pbk) Printed in Great Britain by Bookcraft (Bath) Ltd Midsorner Norton, Avon Preface This book might have been entitled ‘A History of Physical Chemistry’, which to some extent it is. I am not, however, a historian, and my object has been somew hat dillerent from that of a historian. I wanted primarily to give scientists some insight into how one important branch of physical science has developed. At the same time I have tried to write the book in such a way that historians of science who are not also scientists may find the book useful, even though they may well w ant to skip over some of the early material with which they will be familiar, and perhaps some of the more mathematical parts. A science like physical chemistry is not necessarily best taught in the first instance by a purely historical approach. A historical approach to science does, however, have important uses. For one thing, the teaching of science can be more effective if the teacher has some knowledge of its history. An account of some personal incident that occurred during the course of scientific work can greatly arouse the interest of students. I have found, for instance, that the story of Arrhenius’s difficulties with his Ph.D. examiners always seems to go down well with students, and seems to make them think that electrolytic dissociation is perhaps not such a dull subject after all. There are benefits of a more basic kind. Ideas sometimes seem obvious to us simply because we have been brought up to believe them. Teachers are inclined to think it self-evident that the second law of thermodynamics is a statistical law, and may be impatient with students who can not see at once that this is so. It is helpful to know that Clausius, who did as much as anyone to establish the second law, believed all his life that it is a purely mechanical law, and that for a year or so Boltzmann thought the same. Lord Kelvin, who was also a pioneer in formulating the second law, never understood the idea of entropy at all. Appreciating these facts must help us to teach the second law more effectively to our students. When scientists write the history of their subject, historians often complain that they write ‘Whig’ history, meaning that they write the history from the standpoint of the present day, failing to put themselves in the position of the scientists who were making the discoveries. Perhaps in a book like the present one a certain amount of Whiggery may be justified, but I have nevertheless been at some pains to discuss a number ol ideas that eventually led to dead ends but wTich were often fruitful in leading to further work which sometimes had the object of disproving them. In order not to distract the reader with superscript references throughout the text I have simply included an alphabetically arranged bibliography at the end, sometimes with explanatory notes. It should always be easy to relate the refer¬ ences to the names and dates in the text. v vi PREFACE Brief biographies of many of the scientists mentioned in the book are to be found at the end, and longer biographies of a selected few are distributed throughout the text. It will be obvious that I have not chosen, for the more detailed treatments, those who have made the most important contributions. Instead I have included people whose lives are of particular interest, and a few whose contributions to science seem to have been underrated. Many readers of this book will feel that I have omitted topics that ought to have been included. To avoid excessive length I have kept to what in my view are the main trends in the overall development of the subject. Some topics, although in themselves of great importance, have been omitted since they seemed to me to be branches rather than the main growth itself. Different views of the subject are indisputably of equal validity. Ottawa K.J. L. June, 1992