ATKINS' PHYSICAL CHEMISTRY Eighth Edition Peter Atkins Professor of Chemistry. University of Oxford, and Fellow of Lincoln College,Oxford Julio de Paula Professor and Dean of the College of Arts and Sciences Lewis and Clark College, Portland,Oregon W.H.Freeman and Company New York
ATKINS’ PHYSICAL CHEMISTRY Eighth Edition Peter Atkins Professor of Chemistry, University of Oxford, and Fellow of Lincoln College, Oxford Julio de Paula Professor and Dean of the College of Arts and Sciences Lewis and Clark College, Portland, Oregon W. H. Freeman and Company New York
Preface We have taken the or ortunity to refresh both the content and r sentation of this text while as for all its editions keep broad in scope,and authoritative.The bulk of textbooks is a perennial concern:we have sought to tighten the presentation in this edition.However,it should always be borne in mind that much of the bulk arises from the numerous pedagogical features that we in de (such as Worked examples and the Data section),not necessarily from mtation is the use of colour.We hav e made every e but usin ptsand data more clearly.The text is still divided into three parts.but material has been moved between chapters and the chapters have been reorganized.We have responded to the shift in emphasis away from classical thermodynamics by combining several chapters in Part 1 (Equilibrit m),bearing in mind that some of the material will already have n covered in earlier cour: We no longer make a distinction betwe rium electrochemistry now finds a home within the chapter on chemical equilibrium where space has been made by reducing the discussion of acids and bases. In Part 2(Structure)the principal changes are within the chapters,where we have sought to bring into the discussion contemporary techniques of spectroscopy and hemistry.In re in mate ywith Part 3 has lost its cha but not the material.We egard this material as highly important in a contemporary context,but as a final chapter it rarely received the attention it deserves.To make it more readily accessible within the context of courses and to acknowledge that the material it covers is at home intellectually with other material in the book,the description of electron transfer reactions is ow a part of the sequenc on chemi cription o pr ed h ne genera fully d and ovter p applied to biology.materials.and the environment.By liberating these topics from their boxes,we believe they are more likely to be used and read;there are end-of- chapter problems on most of the material in these sections. In the preface to the seventh edition we wrote that there was vigorous dis ssion ir the physic oice or a quantum nrst or a 'thermo app hle The wenave d partic make it h the t de n and of this Preface w onc ain include tw u and at the sted road maps The concern expressed in the seventh edition about the level of mathematical ability has not evaporated,of course,and we have developed further our strategies for showing the absolute centrality of mathematics to physical chemistry and to make it accessible.Thus,we give more help with the development of equations,motivate
Preface We have taken the opportunity to refresh both the content and presentation of this text while—as for all its editions—keeping it flexible to use, accessible to students, broad in scope, and authoritative. The bulk of textbooks is a perennial concern: we have sought to tighten the presentation in this edition. However, it should always be borne in mind that much of the bulk arises from the numerous pedagogical features that we include (such as Worked examples and the Data section), not necessarily from density of information. The most striking change in presentation is the use of colour. We have made every effort to use colour systematically and pedagogically, not gratuitously, seeing as a medium for making the text more attractive but using it to convey concepts and data more clearly. The text is still divided into three parts, but material has been moved between chapters and the chapters have been reorganized. We have responded to the shift in emphasis away from classical thermodynamics by combining several chapters in Part 1 (Equilibrium), bearing in mind that some of the material will already have been covered in earlier courses. We no longer make a distinction between ‘concepts’ and ‘machinery’, and as a result have provided a more compact presentation of thermodynamics with less artificial divisions between the approaches. Similarly, equilibrium electrochemistry now finds a home within the chapter on chemical equilibrium, where space has been made by reducing the discussion of acids and bases. In Part 2 (Structure) the principal changes are within the chapters, where we have sought to bring into the discussion contemporary techniques of spectroscopy and approaches to computational chemistry. In recognition of the major role that physical chemistry plays in materials science, we have a short sequence of chapters on materials, which deal respectively with hard and soft matter. Moreover, we have introduced concepts of nanoscience throughout much of Part 2. Part 3 has lost its chapter on dynamic electrochemistry, but not the material. We regard this material as highly important in a contemporary context, but as a final chapter it rarely received the attention it deserves. To make it more readily accessible within the context of courses and to acknowledge that the material it covers is at home intellectually with other material in the book, the description of electron transfer reactions is now a part of the sequence on chemical kinetics and the description of processes at electrodes is now a part of the general discussion of solid surfaces. We have discarded the Boxes of earlier editions. They have been replaced by more fully integrated and extensive Impact sections, which show how physical chemistry is applied to biology, materials, and the environment. By liberating these topics from their boxes, we believe they are more likely to be used and read; there are end-ofchapter problems on most of the material in these sections. In the preface to the seventh edition we wrote that there was vigorous discussion in the physical chemistry community about the choice of a ‘quantum first’ or a ‘thermodynamics first’ approach. That discussion continues. In response we have paid particular attention to making the organization flexible. The strategic aim of this revision is to make it possible to work through the text in a variety of orders and at the end of this Preface we once again include two suggested road maps. The concern expressed in the seventh edition about the level of mathematical ability has not evaporated, of course, and we have developed further our strategies for showing the absolute centrality of mathematics to physical chemistry and to make it accessible. Thus, we give more help with the development of equations, motivate
PREFACE them.iustify them.and comment on the steps.We have kept in mind the struggling student,and have tried to provide help at every turn. We are,of course,alert to the developments in electronic resources and have made a special effort in this edition to encourage the use ofthe resources on our Web site(at hfreeman.com/pchem)where you can also acces the eBook.Ir itimportant ton nts to s an in the text),we include ho t splore the coneucn changing parameters Overall,we have taken this opportunity to refresh the text thoroughly,to integrate applications,to encourage the use of electronic resources,and to make the text even more flexible and up to date. Oxford
vi PREFACE them, justify them, and comment on the steps. We have kept in mind the struggling student, and have tried to provide help at every turn. We are, of course, alert to the developments in electronic resources and have made a special effort in this edition to encourage the use of the resources on our Web site (at www.whfreeman.com/pchem8) where you can also access the eBook. In particular, we think it important to encourage students to use the Living graphs and their considerable extension as Explorations in Physical Chemistry. To do so, wherever we call out a Living graph (by an icon attached to a graph in the text), we include an Exploration in the figure legend, suggesting how to explore the consequences of changing parameters. Overall, we have taken this opportunity to refresh the text thoroughly, to integrate applications, to encourage the use of electronic resources, and to make the text even more flexible and up to date. Oxford P.W.A. Portland J.de P
PREFACE vii Traditional approach Special topics Chapters 12,18-20,23.and 25 latmc Molecular approach ouant8abeo8a299g9go8copy 86
PREFACE vii
About the book mor s the se and this enormously important aspect of physical chemistry.see Mathematics and Physics support.Problem solving-especially,'where do I start?'-is often a challenge,and ，hewebisaseraordaayCotegmchsrothurcdcsccPHroblemoigfina. but it is necessary to know wh re to start more det ng paragrap Organizing the information Checklist of key ideas Checklist of key ideas Here we collect together the major chapter.We sugs acc.p-AT.Vn entry when you feel confident about the topic. 产b0 on of the h ist.The cri 0 Impact sections ons:the principl nd smaller elec d m how h ncinles do d the chapter rbinedre ofd :SWNI. contexts. 75
About the book There are numerous features in this edition that are designed to make learning physical chemistry more effective and more enjoyable. One of the problems that make the subject daunting is the sheer amount of information: we have introduced several devices for organizing the material: see Organizing the information. We appreciate that mathematics is often troublesome, and therefore have taken care to give help with this enormously important aspect of physical chemistry: see Mathematics and Physics support. Problem solving—especially, ‘where do I start?’—is often a challenge, and we have done our best to help overcome this first hurdle: see Problem solving. Finally, the web is an extraordinary resource, but it is necessary to know where to start, or where to go for a particular piece of information; we have tried to indicate the right direction: see About the Web site. The following paragraphs explain the features in more detail. Organizing the information Checklist of key ideas Here we collect together the major concepts introduced in the chapter. We suggest checking off the box that precedes each entry when you feel confident about the topic. Impact sections Where appropriate, we have separated the principles from their applications: the principles are constant and straightforward; the applications come and go as the subject progresses. The Impact sections show how the principles developed in the chapter are currently being applied in a variety of modern contexts. Checklist of key ideas 1. A gas is a form of matter that fills any container it occupies. 2. An equation of state interrelates pressure, volume, temperature, and amount of substance: p = f(T,V,n). 3. The pressure is the force divided by the area to which the force is applied. The standard pressure is p7 = 1 bar (105 Pa). 4. Mechanical equilibrium is the condition of equality of pressure on either side of a movable wall. 5. Temperature is the property that indicates the direction of the flow of energy through a thermally conducting, rigid wall. 6. A diathermic boundary is a boundary that permits the passage of energy as heat. An adiabatic boundary is a boundary that prevents the passage of energy as heat. 7. Thermal equilibrium is a condition in which no change of state occurs when two objects A and B are in contact through a diathermic boundary. 8. The Zeroth Law of thermodynamics states that, if A is in thermal equilibrium with B, and B is in thermal equilibrium with C, then C is also in thermal equilibrium with A. 9. The Celsius and thermodynamic temperature scales are related by T/K = θ/°C + 273.15. 10. A perfect gas obeys the perfect gas equation, pV = nRT, exactly 12. The partial pressure of any gas i xJ = nJ /n is its mole fraction in a pressure. 13. In real gases, molecular interact state; the true equation of state i coefficients B, C, . : pVm = RT 14. The vapour pressure is the press with its condensed phase. 15. The critical point is the point at end of the horizontal part of the a single point. The critical const pressure, molar volume, and tem critical point. 16. A supercritical fluid is a dense fl temperature and pressure. 17. The van der Waals equation of s the true equation of state in whi by a parameter a and repulsions parameter b: p = nRT/(V − nb) − 18. A reduced variable is the actual corresponding critical constant IMPACT ON NANOSCIENCE I20.2 Nanowires We have already remarked (Impacts I9.1, I9.2, and I19.3) that research on nanometre-sized materials is motivated by the possibility that they will form the basis for cheaper and smaller electronic devices. The synthesis of nanowires, nanometre-sized atomic assemblies that conduct electricity, is a major step in the fabrication of nanodevices. An important type of nanowire is based on carbon nanotubes, which, like graphite, can conduct electrons through delocalized π molecular orbitals that form from unhybridized 2p orbitals on carbon. Recent studies have shown a correlation between structure and conductivity in single-walled nanotubes (SWNTs) that does not occur in graphite. The SWNT in Fig. 20.45 is a semiconductor. If the hexagons are rotated by 60° about their sixfold axis, the resulting SWNT is a metallic conductor. Carbon nanotubes are promising building blocks not only because they have useful electrical properties but also because they have unusual mechanical properties. For example, an SWNT has a Young’s modulus that is approximately five times larger and a tensile strength that is approximately 375 times larger than that of steel. Silicon nanowires can be made by focusing a pulsed laser beam on to a solid target composed of silicon and iron. The laser ejects Fe and Si atoms from the surface of the