To learn organic chemistry well, we must master the characteristics of organic chemistry. The following summarizes the characteristics of organic chemistry. If we follow the following methods to remember and learn, we will get twice the result with half the effort.
Organic chemistry is an important part of middle school chemistry. Because of its variety, complex structure and close connection with production and life, it has become a hot spot in college entrance examination. Many students complain that organic chemistry is difficult to learn, even becoming a differentiation point of chemistry learning. Based on this phenomenon, the author summarized and analyzed the common difficulties of students in learning organic chemistry, and summarized some learning methods of organic chemistry combined with his own teaching.
1、 The Structure of Organic Matter -- the Basis of Studying Organic Chemistry
When first exposed to organic chemistry, students will notice the difference between organic chemistry and inorganic chemistry, and pay great attention to the explanation and examination of material structure. Every time we talk about an organic substance, the teacher will spend a lot of time explaining the structure of the substance and showing the stick model and scale model of the substance. In ordinary practice, we often have questions about the structure of such substances, such as whether the carbon atom is in a plane or in a straight line. In class, students should seize the opportunity of the teacher to show the model, observe and think more, and grasp the structural characteristics of typical substances. After class, students should use the materials around them, such as toothpicks or sticks to represent keys, and fruits, small clay balls, flour balls, etc. to represent various atoms, to assemble structural models of various substances and experience the structural characteristics of various substances.
2、 Structure determines nature -- a magic weapon for learning organic chemistry
The central problem of organic chemistry is the relationship between structure and property. Grasping the relationship between structure and property is a magic weapon to learn organic chemistry well. From the structural characteristics of organic compounds, it can be well understood that the main properties of organic compounds include physical properties and chemical properties.
In terms of physical properties, hydrocarbons are generally non-polar or weakly polar molecules. The intermolecular force is relatively small, so the melting and boiling points of hydrocarbons are relatively low, and they are generally insoluble in strong polar solvents (water); The intermolecular force of hydrocarbon derivatives increases with the increase of functional group polarity, and their melting point and boiling point are higher than those of hydrocarbons with the same relative molecular weight. For example, the boiling point of ethanol is 78 ° C, 120.07 ° C higher than that of propane with the same relative molecular weight.
From the perspective of chemical properties, the carbon carbon single bond structure of alkanes determines the stability of their chemical properties, and the substitution reaction is its characteristic reaction; The double bond and triple bond in unsaturated hydrocarbon are easy to break due to one or two of them, and their chemical properties are relatively active. Addition and polymerization are their characteristic reactions; Benzene and its aromatic hydrocarbons have dual properties of saturated and unsaturated hydrocarbons due to the particularity of benzene ring structure, which can not only take place substitution reaction but also take place addition reaction. The properties of hydrocarbon derivatives depend on the properties of functional groups, such as ethyl formate and glucose. Although they are not aldehydes, they all contain aldehyde groups, so they all have the main properties of aldehydes (such as silver mirror reaction, etc.). From the perspective of structure, formic acid (HCOOH) has both - COOH and - CHO, so formic acid has the dual properties of carboxylic acid and aldehyde. Therefore, it is necessary to analyze and master the properties of hydrocarbon derivatives according to the types of functional groups.
From the perspective of structure determining nature, the study of organic chemistry generally has its fixed rules and methods: typical material structure → property → use → preparation → class I material. When sorting out knowledge after class, we should follow this clue to achieve twice the result with half the effort.
3、 Connect well - promote knowledge integration
In the study of organic chemistry, in addition to mastering the structure and nature of various organic substances, it is more important to master the mutual transformation relationship between organic substances, clarify the connection between knowledge, form a knowledge network, have a comprehensive understanding of organic chemistry in middle school, and achieve the purpose of integrating knowledge. Hydrocarbons can be converted into halogenated hydrocarbons through substitution or addition reaction, halogenated hydrocarbons can be converted into alcohols through substitution reaction, alcohols can be oxidized into aldehydes, aldehydes can be oxidized to generate acids, carboxylic acids and alcohols reaction products are esters, the essence of this conversion relationship can be expressed as (where X and R represent a certain group):
This is the main knowledge of organic chemistry, and is one of the "information items" with the most frequent occurrence of organic block diagram questions and inference questions. Students can use this main line to sort out knowledge and form an organic whole knowledge system.
4、 Learn to Dialectically Analyze Reasoning the Nature of Organic Matter
In the study of organic chemistry, we can deduce the properties of homologues by understanding the properties of one or several compounds, so as to systematize and regularize large organic objects, which is the basic method of learning organic chemistry. However, while considering the universal connection of matter, we should also recognize its development and particularity, which requires us to use the world outlook and methodology of dialectical materialism to understand the knowledge of organic chemistry more comprehensively and profoundly. Ethanol, phenol, acetic acid and glucose all contain hydroxyl, so they can react with metal sodium to release hydrogen, which is the universality of substances containing hydroxyl. However, due to the different groups connected to hydroxyl, the interaction between groups results in obvious differences in the properties of hydroxyl. For example, ethanol and glucose solutions are neutral, phenol solutions are weakly acidic, and acetic acid solutions are obviously acidic, which is the dialectical relationship between universal connection and interaction. There are many dialectical relations contained in organic chemistry. The key is to be able to make specific analysis of specific problems when learning organic chemistry, to make flexible judgments and treatments according to the internal characteristics and external conditions of things, and to develop the habit of dialectical thinking.
Senior one students in my school are learning organic chemistry. As they are new to organic chemistry, students generally report that it is difficult to learn organic chemistry. They can't grasp the key points when listening to lectures, and can't start with new questions when practicing. In fact, throughout the three years of senior high school, organic chemistry is much easier to learn than inorganic chemistry. As long as you grasp the core idea of "structure determines nature, and nature reflects structure", master the structure and nature of typical substances, establish a network of mutual connections and transformation of knowledge between organic substances, and do more exercises to contact various types of questions, you will certainly eliminate the fear of difficulties and learn organic chemistry easily, Make it the scoring point of college entrance examination chemistry.
If you want to take an organic chemistry major as a graduate student, which schools can you consider if you want to take an organic and physical chemistry major course with a general foundation?
Peking University, Nanda University and Shanghai Organic Institute are also well positioned. Although Beihua is also very good, the pressure is too obvious, followed by Sichuan University, Nankai University and Dahua University, followed by Jida, Beike University and Changchun Yinghua University. If the minimum is guaranteed, there are also Guanghua, Chengdu Organic, Xiamen University, Lanzhou University and Fujian Physical Structure. I will look at them myself. These are all adjustments, but the number of adjustments in Lanzhou University is small and 985, and Fujian's unstable physical structure adjustment is easy to be jointly trained. We recommend our tutor, Daniel. It's estimated that he is a little more than Shi Zhangjie of Peking University. It's not difficult for me to pass the exam. I was assigned to the post sleep class and transferred there. But there are many people who applied for him. Feng Xiaoming of my undergraduate school can also consider it. What can organic chemistry major do?
The scope of organic chemistry is too wide. It is better to choose organic chemistry for more social purposes. It is better to choose more carefully, so that the employment direction is more appropriate. I majored in polymer materials, and it's OK to work in the south, but I still think that electrochemistry is better for boys, and fine chemical industry is better for girls.
Organic chemistry and analytical chemistry majors now have good employment scope in large and medium-sized cities. For example, the monthly salary of some large pharmaceutical companies has reached at least 5000 yuan; Even if you don't enter such a company, it is also easy to find jobs in public institutions, such as schools, such as inspection and quarantine bureaus.
In a word, the major direction in chemistry must be selected. In short, the major with strong application is easy to find a job in any organization!
The organic chemistry in college is a little difficult. How can I learn it?
For science students, chemistry should be a little basic liberal arts students, it is relatively difficult. The learning methods introduced here are mainly for science students. Only science students can choose professional courses related to chemistry in universities. Chemistry is difficult. Otherwise, no students will complain about the difficulty of organic chemistry. Now let's introduce the learning methods.
First of all, if you are a science student and your major in college is chemistry, I suggest you read the high school chemistry book again. Of course, if you have a good foundation, you don't need to read it. This is the most basic. You need to understand the knowledge about organic chemistry involved in high school before you can enter the next higher stage.
Secondly, college organic chemistry needs to be previewed before class. Don't think it doesn't matter to go to college. If your major is this, it is necessary to learn it well. The organic part of college is that it is quite difficult to preview. Just make a preparation, and you should listen well in class. If you don't understand, you should ask, discuss more, and if you don't understand, you can ask teachers or classmates.
Moreover, after class, we should actively find some models to observe, or do more experiments, which will help you understand. You should also find a learning method that suits you. Don't copy others. Sometimes their learning methods may not suit you. Your own learning method is the most suitable and effective for you. The stupidest way is to watch it several times, again and again, to understand. If you don't understand, ask the teacher or students. Don't be afraid to ask too many questions, and don't be afraid of being laughed at.
The foundation of learning is to establish a basic knowledge structure system and have a general understanding of organic chemistry. I believe that with these methods, learning will be relatively simple.
