Physical Chemistry

Physical chemistry is the subject which uses the theory and concept in physics to study the basic principles and chemical reactionsin chemistry. It has been founded as a chemical subject for about 200 years.

There is a wrong view that physical chemistry is a physical subject rather than a chemical one. This may result from its large number of formula and boring theorem. In fact, physical chemistry is a subject whose concentration is ultimately on the application in chemistry. While the theories such as motion, energy and quantum mechanics is only the methods borrowed from physics.

Physical chemistry can be roughly sorted into four parts, including thermodynamics, dynamics, electrochemistry and structural chemistry. Thermodynamics studies the limitation and direction of chemical reaction, mixing process, phase transition and other atom-scale process. Dynamics points at the speed of chemical reactions. Electrochemistry is about the electronic phenomenon and electric process in chemical reaction, which is extremely useful in battery, plating and electrolysis. Structural chemistry is more complex than the three former aspects for it involves quantum mechanics.

Physical chemistry has successfully solved lots of vital problems which made innumerable social wealth in these 200 years. In my opinion, with the development of other related fields, the researching methods, fundamental theorems and other derived empirical equationsof physical chemistry will be used more and more widely in chemicalengineering.

 

第二篇：高考英语写作系列-事物说明(说明文)

事物说明(说明文)优秀范文The Chinese People’s Dream中国人的梦想The Chinese people have been dreaming of going into space for a long time. In the years 1999 to 2002 China launched three unmanned spacecrafts successfully. On Dec. 31th, 2002, the launch of the fourth spacecraft “Shenzhou Ⅴ” was another big success and the spacecraft returned to the earth safe on January 5th, 2003. During its flight, seven scientific experiments were carried out. The purpose of the flight is to make preparations for the launch of a manned spacecraft next time. The successful launch and return shows that China is able to send a person into space soon. In 2003, the first manned spacecraft is expected to be sent into space. By then the Chinese dream has come true.have been dreaming of going into space.一直梦想进入太空。unmanned spacecraft 无人驾驶飞船during its flight 在飞行期间carry out 开展，进行make preparations for 为……作准备be able to send a person into space 有能力载人进入太空by then 到那时Mobile Phones手机Great changes have been taking place in the ownership of mobile phones in China. At the end of 2002, there were 20 million mobile phone users. By the year 2005, the number will reach up to 30 million.People have found mobile phones very convenient. They can get in touch with each other whenever and wherever they like. Moreover, there are many different functions for different needs, such as sending short messages and surfing the Internet. However, it may also bring us some trouble. For example, you will have to pay for a wrong number, and the radiation from the phone may do harm to our health. In spite of this, the number of people having mobile phones is still increasing steadily.Great changes have been taking place in the ownership of mobilephones in China. 在中国，手机的拥有量发生了很大的变化。reach up to 达到They can get in touch with each other whenever and wherever they like.他们能随时随地取得联系。send short messages and surf the Internet 传送短信和上网The radiation from the phone may do harm to our health.手机的辐射或许对我们的身体有害。My Favorite Newspaper我最喜爱的报纸21st Century is my favourite newspaper. It is an English language newspaper, which is published in Beijing each week. It has sections of different kinds, including News of the week, Today’s World, Language Class, Sports and Music and Students Report. There are plenty of beautiful pictures and interesting articles in it. I enjoy reading the paper. I read it to improve my English. I have learnt a lot of new words and useful expressions from it. Besides, I can get information about different things, from politics to sports and music. 21st Century is very popular with students and English learners. I do love it.sections of different kinds 不同的版面plenty of

大量，许多useful expressions 常用表达be very popular with 很受欢迎 I do love it. 我非常喜欢它。My Family’s Yard我家的院子I think that my family’s yard is about 0.78 acres. It has trees, flowers, vegetables and a small hill.There’s a path of bricks that are laid out on the ground by the front door, it separates my yard in half from north to south. On the front right side of the brick path, two large Japanese peach trees are planted. Every August is picking season, and the peaches are very big and delicious. If we don’t hurry and pick the peaches, they’ll drop all over the ground and if you accidentally step on one, the peach juice will make your shoes turn blood red.Behind the peach trees lies a very big plum tree, it has a mass of branches and leaves. This year was very dry, we didn’t spray enough water, therefore we didn’t get to pick plums. On the other side there’s a big oak tree. The tree branches are very thick and I frequently wrap a piece of rope around the branch and use it as a swing for playing.On the left of the brick path there’s a row of small trees separating the front and back halves. In the front, there’s a garden, in the garden there are cockscombs, hydrangeas and roses; it is very colorful and pretty. The breeze carries with it, the faint scent of flowers. If you just gently inhale the smell, it makes you feel really good.Behind the little trees, there’s a big garden of vegetables. In the garden there are potatoes, lettuces, tomatoes and peppers. Every year there are always vegetables left over. Behind this garden, there’s a grape trellis and on the trellis there are grapevines.Beside the grape trellis, there’s a small hill. My brother and I would always climb onto the hill and back down playing hide and seek.I really like my yard and the trees, flowers, vegetables and the small hill.Genius only means hard working all one’s life.天才仅仅意味着终生不懈的努力。lay out 计划，设计separate my yard in half from north to south 把院子从北到南分开picking season 收获季节turn blood red 变成血红色plum 李子oak 橡树tree branches 树枝cockscomb 鸡冠花hydrangea 八仙花lettuce 莴苣pepper 胡椒trellis 格子grapevine 葡萄树My Favorite Program—“Animal Word”我最喜欢的电视节目——“动物世界”“Animal word” is my favorite program. First, I like small animals very much. Second, the host has the ability to make the program lively and interesting. Third, from the program I gained a lot of knowledge about animal life, which I didn’t know before. By watching the program I understand the relationship between people and animals and between people and nature. Also I know the importance of nature protection.I know animals are part of nature. They cannot be separated from the humans. If the humans want to live wel

l, we must keep nature in balance.Finally, we should let everyone understand this and show our love toward nature and animals and stop doing harm to them.the host 主持人gain a lot of knowledge 获得大量的知识 the relationship between people and animals and between people and nature 人与动物、人与自然之间的关系the importance of nature protection 自然保护的重要性keep nature in balance 保持生态平衡My Experience in Examination考试经历Talking of examinations, I feel that they are one of the important activities in our school life. All through my school days, I have gone through all kinds of examinations and I have tasted the flavor of happiness, sadness and laughter.Before every examination, there is always a certain time for me to suffer. During examinations, I am nervous and my heart beats hard. After examinations, the world seems to be bright again and I become lively again. We often blame the teachers for making trouble for us on purpose, but in fact, it is unfair to say so.talk of 谈起，谈到all through my school days 整个学校生活go through 经历，遭受a certain time 某一时间blame the teachers 责备老师on purpose 有意，故意Our School 我们的学校Our school lies at the foot of a small hill. A little river passes by it. A chemical works was built south of our school two years ago. A great deal of poisonous gas had been sent out into the air and a large amount of waste water had been poured into the river. The terrible pollution had done great harm to us as well as to the surroundings.Now, the government has taken many steps to protect our surroundings and prevent it from being polluted. Now, as you see, our school looks like a beautiful garden. In our schoolyard there are green trees and all kinds of flowers all the year round.at the foot of 在脚下 south of our school 学校南面a great deal of poisonous gas 大量的有毒气体send out 发出，释放出 a large amount of 大量do great harm to 对……有害prevent...from 阻止……免于…… as you see 正如你所看见的all the year round 整年Computers in China中国的电脑According to a recent investigation, about 30% of the city families have computers. Besides, many village people are more and more interested in computers and some of them even have bought computers. About 70% of the parents bought computers for their children to study, and some for their work. And even some people bought them for entertainment. The fact how the middle school students use the computers really surprises us. Only about 30% of them use computers to find out useful information. About 60% of them use computers to chat with other people on the Internet. What is worse, about 60% use computers to play games and 20% use computers to watch VCDs or listen to music. In my opinion, we should make better use of our best invention

-computers.according to a recent investigation 根据最近的调查many village people 许多村民 find out useful information 查找有用的信息chat with other people on the Internet 在网上聊天what is worse 更糟的是in my opinion 依我看来make better use of 更好地利用Our English Corner我们的英语角Our English Corner was set up a year ago. Every Sunday afternoon, students from different classes gather around here. Hundreds of students have been here since it appeared. In the corner, we practise English with each other. Many teachers often join in the activities of our English Corner, too. We talk in English about everything that we are interested in. We usually have many topics to talk about at the English Corner, such as your hobby, your family, your hometown and so on. We can also learn by heart some usual expressions and greetings. We also learn English songs, play English games and so on. We all have a good time here. We feel that we have learned a lot that can’t be learned in English classes. So our English Corner has become necessary and more and more popular among middle school students, their parents and teachers.If you want to know more about the corner, join us.set up 建立hundreds of students 几百个学生join in the activities of our English Corner 加入我们的英语角活动such as your hobby 例如你的爱好usual expressions 常用表达 more and more popular 越来越流行A Good Habit—Early Rising一个好习惯——早起Early rising is a good habit for everyone. It is beneficial to us in many ways. Firstly, it helps to keep us healthy. We can breathe the fresh air in the morning. It’s fun for us to take a walk along the street. Secondly, early rising helps us with our studies. When we get up very early in the morning, everything around us is quiet. In the morning we learn more quickly and memorize what we learn easily. Thirdly, early rising gives us enough time to get ready for our work, such as to wash our hands and faces and to eat breakfast properly. a good habit 好习惯in many ways 在许多方面take a walk 散步help...with 帮助某人做某事get ready for 准备做某事Please Protect Your Eyes.请保护好你的眼睛Now more and more students, senior or junior, even the pupils in primary schools, are near-sighted. For example, sixty percent of the students in our class wear glasses. How serious the situation is! What cause them to be near-sighted? It is because we read books all day, so eyes are too tired. At the same time, most of us don’t pay attention to the right posture of writing. It is well-known that eyes are the important part of our body.We use them to see all the things around us.Without eyes we can not study or work well.So people say eyes are the window of the soul.Of course,glasses are a great help if we are near-sighted.But it is inconvenient with glasses on your f

ace. Though everyone knows the importance of our eyes, not all of us understand how to protect them. I think, first, after we have worked for about an hour or so, we’d better let our eyes have a rest—either close the eyes for a short time or look into the distance. Second, we should’t read in the sun, or in a poor light, or in a moving bus, and do remember reading on bed is a bad habit.Third, we should pay attention to the distance from eyes to the book. Don’t read too close to the book. Finally, we should insist on doing eye-exercise every day. In short, we should try our best to keep our eyes bright.primary schools 小学near-sighted 近视How serious the situation is! 这种情况多严重啊!pay attention to 注意the right posture of writing 正确的书写姿势Eyes are the window of the soul. 眼睛是心灵的窗户.insist on doing eye-exercise 坚持做眼保健操A Ten-Minute Break课间十分钟As students, we have classes from early morning till late afternoon. Therefore, to take a ten-minute break between classes is very important and necessary. Otherwise, we will feel tired.During the ten-minute break we do something to get rid of our tiredness. What we need most is to have a good rest instead of doing more things and getting more tired. So we shouldn’t do anything that can make us too excited.My ten-minute break is always pleasing. I usually do some simple exercises, for example, have a chat with others, take a walk and so on. When the next class begins, I feel fresh and comfortable.have classes from early morning till late afternoon 从早到晚上课therefore 因此get rid of our tiredness 消除疲劳have a good rest 好好休息instead of 代替，顶替have a chat with others 和其他人聊天描写本类主题常用语言集锦The international Olympic Committee constituted itself on 23rd June 1894.国际奥委会于1894年6月23日成立。My new dress is similar to the one you have.我的新衣服和你的那件很相似。The car is made up of many different parts.汽车是由不同的部件构成的。A personal computer has three simple and clear parts.个人计算机由简洁的三部分组成。The telephone makes things easy in many ways.电话在许多方面给人带来方便。The telephone is one of the most welcome and useful things.电话是最受欢迎、最有用的东西之一。The telephone can shorten the distance from their parents.电话可以缩短他们与父母的距离。The telephone is especially important. 电话尤其重要。We can’t live without the telephone in our daily life.我们在日常生活中离不开电话。That bird is very rare in this country. 那种鸟在这个国家很稀少。Don’t forget to change its water every day. 不要忘了每天换水。Alone is a kind of the most popular natural plant.芦荟是最流行

的一种天然植物。It is valuable not only for watching, but also for using.它不仅具有观赏功能，而且有使用价值。It has many thick leaves with some small needles.它有大量的带有一些小刺的肥厚的叶子。The leaves are straight. 叶是直的。Its flowers are very beautiful. 花很美。They are afraid of coldness. 它们害怕寒冷。It can be made into food. 它能做成食品。This apple tree grows from tiny seeds. 这棵苹果树是从极小的种子长大的。