(1.3.1)--3.VanHoff_firstwinner.pdf

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1、范特霍夫范特霍夫-第一第一届诺贝尔化学奖得主届诺贝尔化学奖得主 Jacobus Henricus Van t Hoff-The First Nobel Prize Winner in Chemistry We all know that the Nobel Prize began in 1901.But do you know who is the first Winner of Nobel Prize in Chemistry in 1901?He is Jacobus van t Hoff!PART ONE Biography Jacobus van t Hoff won the Nobe

2、l Prize in Chemistry in 1901.He worked at Berlin University,Germany.His Prize motivation was for the extraordinary services he has rendered,by the discovery of the laws of chemical dynamics and osmotic pressure in solutions.Jacobus van t Hoff is considered one of the founders of physical chemistry.A

3、lthough many people thought Vant Hoff was a German Scientist,actually he was born in Netherlands.After he obtained his PhD,he was a professor in Amsterdam for many year.Universiteit Utrecht But in 1896 he moved to Berlin,where he was offered a position,with more research and less teaching.He formula

4、ted the osmotic pressure law,but also was important in stereochemistry for molecular structure.At a fundamental level,chemistry deals with how molecules are composed of atoms and how atoms and molecules come in contact and form new substances.During the 1870s and 1880s,Jacobus van t Hoff made pionee

5、ring contributions,with respect to both the structure of molecules and various sequences of events.PART TWO Achievement Now you may ask what is osmosis?Osmosis is he phenomenon that two different concentrations of solution are separated by membrane.The membrane that allows solvent molecules to pass

6、through,which does not allow solute molecules to pass.As we can see from the picture here,water molecules or other pure solvent molecules from a low concentration solution pass through a semi-permeable membrane into a high concentration solution,until the concentrations of the separated two parts ar

7、e equal.Applied pressure is needed to stop osmosis.Contributions to chemistry Before receiving his doctorate,van t Hoff had already published the first of his important contributions to organic chemistry.In 1874 he accounted for the phenomenon of optical activity by assuming that the chemical bonds

8、between carbon atoms and their neighbors were directed towards the corners of a regular tetrahedron.This three-dimensional structure perfectly accounted for the isomers found in nature(stereochemistry).He shares credit for this idea with the French chemist Joseph Le Bel,who independently came up wit

9、h the same idea.In 1884 van t Hoff published his research on chemical kinetics,naming it Studies in Chemical Dynamics(tudes de Dynamique chimique),in which he described a new method for determining the order of a reaction using graphics,and applied the laws of thermodynamics to chemical equilibria.H

10、e used the principles of thermodynamics to provide a mathematical model for the rates of chemical reactions,based on the changes in the concentration of reactants with time.Van t Hoff showed how the previously independently developed concepts of dynamic equilibrium(that chemical equilibrium results

11、when the rates of forward and reverse reactions are equal),the law of mass action(that the concentration of substances affects the rate of reaction),PART THREE Birth of physical chemistry and the equilibrium constant(the ratio of the concentrations of starting materials to products at equilibrium)to

12、gether formed a coherent model for understanding the nature of chemical reactions.Finally,he showed mathematically how temperature,pressure,and mass affected the rate of chemical reactions and how the heat generated by a reaction could be calculated from the mathematical equation that governs the fi

13、nal equilibrium state.This relationship between heats of reaction and equilibrium allowed van t Hoff to define the modern concept of chemical affinity.On the basis of his innovative and successful treatment of chemical affinity,van t Hoff was awarded the first Nobel Prize for Chemistry in 1901.So to

14、days class,I have introduced you Jacobus van t Hoff,the founder of physical chemistry and the first Nobel Prize Winner in Chemisty in history.Thanks for your watching!思思 考考 据说，范特霍夫在牧场养了许多奶牛，每天早上的任务就是把牛奶送给居民喝。即使在深冬的清晨，德国柏林郊区的街道也有一辆马车疾驶而过，但谁都不会想到，原来那个每天早上驾车为大家送奶的人，竟是著名的化学家。因为在化学动力学和化学热力学研究上的贡献，范特霍夫获得1

15、901年的诺贝尔化学奖，成为史上第一位获得诺贝尔化学奖的科学家。这当然与他自幼热爱化学和在数学、物理学等方面的广博而深厚的知识素养分不开。然而，注意哲学修养、不断探求科学方法更使他具有非凡的创造想像能力，小时候对化学实验的浓厚兴趣，后来变成了他取得各项成果的基础。他重视实验，但又不像当时绝大多数科学家那样局限于狭隘的经验。他善于巧妙地运用数学方法去整理实验结果，并注意用类比等逻辑推理从数学方程式里面推导出一些理论上的新结论，这是他创立物理化学新学科的重要方法。而在立体化学创立过程中，则主要体现了他对模型方法以及科学假说方法的深刻理解和灵活应用，他总是站在哲学的高度去把握问题的精髓，胜人一筹。W

16、hat is osmotic pressure?Lets listen to what he said in 1901 “It was found namely that with sufficiently dilute solutions the osmotic pressure was the same as the gas pressure,i.e.the pressure which the dissolved substance would exert as gas.To some extent this is obvious:Just as one imagines the gas

17、 pressure P to arise as a result of the movement of molecules and of their collisions with the walls(Fig.1),so can one imagine the osmotic pressure p to arise as a result of the collisions of the dissolved molecules with the semi-permeable membrane(Fig.2)surrounded by the solvent(denoted by shading)

18、.However,independently of an anyway hypothetical conception on the cause of this pressure,it was found that under the same circumstances,i.e.with the same number of molecules in the same volume and at the same temperature,the pressures also were the same.This can be expressed mathematically by the equation p=P.”