华南理工大学物理化学课件.ppt

1、物理化学电子教案绪论,华南理工大学 应用化学系 物理化学教研组,引用与制作 借鉴与创新 肖士民 2004年,Xiaoshimin1945 sohu. com,Bilingual Education,Ill be teaching you Physical Chemistry this semester.,Preface,In any scientific discipline, a fundamental understanding is more important than learning lists, but this is probably more true in physical

2、 chemistry than in other branches of chemistry .,Lets be clear from the outset-,understanding is the key to physical chemistry, but the maelstrom of mathematics often clouds the students ability to create a comprehensible mental model of the subject.,We Hope,that this text contributes to helping you

3、 reach the level of understanding you need. Understanding the world around you really is one of the thrills of science.,Thus we start with,the basic properties of matter which allows us then to discuss thermodynamics. Thermodynamics leads naturally into equilibria, solutions and then kinetics.,Conte

4、nts,1. States of matter 2. Thermodynamics 3. Equilibria 4. Solutions 5. Kinetics 6. Electrochemistry 7. Thermodynamics of interface layer,Others important chapters,For students of applied chemistry 1. Colloid dispersed system 2. Statistical thermodynamics,The properties of gases,Equations of state:

5、the perfect gas,The physical properties of a perfect gas are completely described by the amount of substance of which it is comprised, its temperature, its pressure and the volume which it occupies.,These four parameters (n,P,V,T),are not independent, and the relations between them are expressed in

6、the gas laws.,The three historical gas laws Boyles law, Charles law and Avogadros principle are specific cases of the perfect gas equation of state, which is usually quoted in the form PV = nRT, where R is the gas constant.,近代化学的发展趋势和特点,(1)从宏观到微观,(2)从体相到表相,(3)从定性到定量,(4)从单一学科到交叉学科,(5)从研究平衡态到研究非平衡态,化学

7、学科的发展趋势,只有深入到微观，才能掌握化学变化的本质和结构与物性的关系。,(1) 从宏观到微观,化学学科的发展趋势,多相化学反应在表相上进行，了解 表相性质，推动表面化学和多相催化的发展。,(2) 从体相到表相,化学学科的发展趋势,计算机技术可进行人工模拟和自动记录，以前只能 做定性研究的课题现在可进行定量监测。,(3) 从定性到定量,化学学科的发展趋势,各学科相互渗透、相互结合，形成交叉科学，如生物物理化学、高分子物理化学、界面与胶体化学、硅酸盐物理化学等。,(4) 从单一学科到交叉学科,化学学科的发展趋势,自1960年以来，逐渐形成了非平衡态热力学这个学科分支。,(5)从平衡态到非平衡态

8、,物理化学的学习方法,(1)演绎法；归纳法。,(2)抓重点，推导公式。,(3)学会解题方法。,(4)自学，复习，思考，解题。,关于物理量的表示及运算,表示式：物理量 = 数值 单位,A = A A,量的符号：斜体、拉丁或希腊字母。,单位的符号：正体、小写字母，人名大写。,braces, square brackets,Attention:,运算：有 量方程式 和 数值方程式。,图 表中 用 数值。,Ln 后 用 数值。 t / = T/k 298.15,Two kinds of question arise in connection with the physical and chemica

9、l transformation of matter. One is Can it occur?,and the other is How fast does it occur?.,T - thermodynamic temperature,Gases are so simple that they provide,an excellent introduction to physical chemistry.,The basic quantities for the study of gases are pressure and temperature.,The Zeroth Law of

10、thermodynamics.,When two systems are each in thermal equilibrium with a third system ,they are in thermal equilibrium with each other.,Deduce the perfect gas equation,1、Boyles law PV = const （const. n and T）,the partial derivative of P with respect to V at constant n and T:,2、 Lussacs law V / T = co

11、nst (const. n and p）,the rate of change of V with respect to T at constant n and P:,How to deduce :,3,Avogadros law V / n = const（const. T and p）,V对n的变化率：,n const:,P1 V1 T1,P2 V2 T2,T const,P2 V T1,P const,P2 V T2,=,V2=V,The perfect gas equation,Use：1、Avogadros law then V2=V a conclusion: only two i

12、ndependent variables. 2、Boyles law then P1 V1 = P2 V 3、Gay Lussacs law then V / T1 = V2 / T2 P1 V1 = P2 V = P2 (V2 T1) / T2 P1 V1 / T1 = P2 V2 / T2 = nR P V = n R T,n - the amount of substance,The methods of deduction,1,the deductive method；2,the derivative method. F (n,P,V,T) = 0 V = f (P,T, n),dV

13、= -V/P dP + V/T dT + V/n dn,d lnV + d lnP = d lnT + d ln n,The derivative method,d ln (PV) = d ln (nT) d ln (PV/nT) = 0 PV / nT = const = R P V = n RT,It is found by experiment that,when the pressure is sufficiently low, all real gases satisfy the perfect gas or ideal gas law.,R,the gas constant, is

14、 a fundamental constant,indepen- dent of the nature of the gas.,Important relation,F (P,V,T) = 0 fP d P + fV d V + fT d T = 0 1、d P = 0 , fV d V + fT d T = 0 (dV/dT)P = - fT / fV 2、d V = 0, fP d P + fT d T = 0 (dT / dP)V = - fP / fT,Merely know that,3、dT = 0, fP d P + fV d V = 0 (d P/d V)T = - fV /

15、fP (d P/d V)T (d V/d T)P (d T/d P)V = -1,Eulers cyclic relation,P V,T,Mixtures of gases: partial pressures,Daltons law of partial pressures states that,The pressure exerted by a mixture of gases behaving perfectly is the sum of the pressures exerted by the individual gases occupying the same volume

16、alone.,P = pA + pB = (nA +nB)(RT / V),That is ,the partial pressure is proportional to the mole fraction.,pA = p xA,Comment. Perfect gas behaviour has not been assumed: the partial pressure,are defined as above for any gas.,Incorporating imperfections,One way of examining imperfect behaviour is to p

17、lot the compression factor Z = pVm/RT as a function of pressure.,For a perfect gas Z is unity under all conditions, and so deviation from unity is a measure of imperfection.,In a pure substance the critical point is the state of highest pressure and temperature at which distinct liquid and vapor pha

18、ses can coexist.,The pressure, temperature and molar volume at the critical point are called the critical pressure pc, critical temperature Tc and critical molar volume V m,c . These are referred to as the critical constants of the gas.,Comparing gases,In order to investigate this point of view we d

19、efine the reduced variables of a gas as the actual variables divided by the corresponding critical constant:,reduced pressure: pr = p/pc ; Vr = Vm / V m,c; Tr = T /Tc,Van der Waals, who first tried this, hoped that the same reduced volume of different real gases at the same reduced temperature would

20、 exert the same reduced pressure. The hope was largely fulfilled.,Think carefully,Turn to page 30. Do the exercises : 1.5 1.9 1.16,The perfect gas equation is one example of an equation of state.,Bilingual Education,Physical Chemistry P. W. Atkins Oxford University Press,Selected from,Preface to the

21、 Second Edition,In preparing the second edition of this book I have taken into account the advice I have received from readers throughout the world.,The principal changes,include a revised introduction to thermodynamics, a strengthening of the sections on quantum theory and molecular structure, and

22、an entirely new chapter on macromolecules.,I have also brought up to date,the sections on X-ray diffraction, magnetic resonance, and surface chemistry.,Wherever possible,I have simplified the notation and the presentation, particularly in the sections on electrochemistry.,The chapters,on statistical

23、 thermodynamics have been restructured into a simpler form.,Every section,of the original edition has been reconsidered in order to improve the presentation, introduce modern material, or to simplify the notation without loss of rigour.,The illustrations,have been revised and the visual presentation

24、 of the material has been improved in a variety of ways, including the use of computer graphics in a novel format.,All the,Tables, Problems, Examples, and Further Reading entries have been reconsidered in detail.,Throughout the revision,however, I have aimed to retain the level of presentation of th

25、e first edition, and to preserve its style and approach.,I owe,a considerable debt to all those who wrote to me with comments either on the first edition or on the draft of the second,Preface to the First Edition,Authors should not preach to teachers. Textbooks should be flexible and adaptable, yet

26、have a strong story line.,I have tried,to conform to these demands by dividing text into three parts, Equilibrium, Structure, and Change.,Each part,begins in an elementary way, drawing on the others only weakly.,Of course,they rapidly get tangled up with each other as they should because the subject

27、 is a unity but teachers will be able to match the text to their own needs without unduly burdening the student.,The student,I hope, will be enticed to read his way into chemistrys web of interdependencies, and will find that he can master them without getting confused.,Physical chemistry,possesses

28、its mathematics for a purpose: there has to be enough mathematical spine in the subject to enable our ideas on the behaviour of molecules and systems to stand up to experimental verification.,Ideas,that cannot be tested do not belong to science.,Nevertheless,in an introductory treatment the ideas mu

29、st not be overborne by the mathematics.,In this text,I show how physical ideas can be developed mathematically, and I take care to interpret the mathematical statements I make.,Only where,the mathematics and the chemistry lose sight of each other is physical chemistry a difficult subject, so I try n

30、ever to let that happen.,These views,have let me to a further organization of the text.,In several places,I have treated a subject in two parts, as “Concepts” and as “Machinery”.,The former,establishes the ideas, while the latter extends and develops them more mathematically.,This is the arrangement

31、,I have adopted for the First and Second Laws of thermodynamics and, later on in Part 2, for statistical thermodynamics.,The “Concepts” chapters,emphasize the underlying physics and let the reader understand the conceptual basis of the subject;,The “ Machinery” chapters,let him discover the ramifica

32、tions of these ideas and show him how to apply them to chemical problems.,Throughout the text,I have used a series of worked examples. These serve two purposes.,The first is to show,how calculations are actually done: an example with all its detailed working can save pages of explanation and give the reader a much clearer impression of what is involved, and a sense of reality.,Their second purpose,is to introduce a remark to extend the text, or to stimulate the readers imagination and interests.,Apart from,the Examp