Science and Comprehensive Selection
21 questions, 126 points, nearly half of the science and technology competition, everyone wants to be sure of victory. I think most people don't worry about science and comprehensive selection, because they usually only get one question wrong in the exam, which doesn't seem to affect the overall situation. However, if you only rely on the sense of questions developed through extensive training and do not have a set of your own problem-solving routines to brush up on the comprehensive selection, you will have an unforgettable experience like my deskmate, "Usually good, but I got two questions wrong in the college entrance examination." The painful experience of "six wrong paths at once". Below I will summarize for you my little thoughts in the process of doing the questions. I hope it will be applicable to you. I also hope that everyone can get full marks in the science and comprehensive selection of the college entrance examination.
For the sake of comprehensive understanding, the time for multiple-choice questions is controlled at about 50 minutes, 40 minutes for easy ones, and one hour for more difficult ones. Don't take too long, and don't rush to finish it in half an hour. I really can't praise the accuracy of this. In the simple science comprehensive selection of the college entrance examination, I still wrote for 40 minutes. This at least ensures that you have sufficient basis for each question and cannot rely on your feelings for one option.
Biology 6 questions
Each option in the biology selection in the college entrance examination will only involve one knowledge point, and there will not be two knowledge points in one option as we usually practice, so skip it One annoying pit after another. But we still need to practice this kind of questions carefully. Such questions help to train our ability to examine questions and force us to read the questions seriously and word for word. This is very important in the college entrance examination.
The questions are roughly 1 for compulsory course 1, 2 for compulsory course 2, and 2 for compulsory course 3. There is also a question that is not directed and may be image synthesis.
For purely basic knowledge questions, there is no need to say more, just read a book. Students who are still good at basic knowledge should go back and study hard. There is always something to chew on if you chew slowly. It is also important to read more books and study plans, record the unfamiliar points in time, and consolidate knowledge in class. During the reading process, you must pay attention to the understanding of concepts, especially in the compulsory course II, you must understand the definitions and examples of the three major variations of various genetic principles and laws, genetic mutation, genetic recombination, and chromosomal variation. Don’t just look at it on the surface, you must take the college entrance examination! ! For the ecological questions in the third compulsory course, you must first distinguish which level it is, including population, community, and ecosystem, and then search for the knowledge points corresponding to this area. I used to always confuse the knowledge points in these three ecological levels. Populations were recorded as communities. After I carefully and completely drew the structural diagram of these three parts, the subordinate relationships of each part were clear at a glance, and then I Didn't miss the question here either.
For material-based questions, let me tell you a high-level research result that you have never seen before. This kind of question generally does not have much impact on problem solving. Don't be frightened and make blind choices just because you don't understand the question. At this time, you need to convert the new information in the question into familiar knowledge before solving the problem. For example, the first question of the 2016 college entrance examination proposed the new concept of ion pump. From the description of the question, we can know that this question is about active transport, and we can use the knowledge of active transport to solve this question.
For image questions, in biology, multiple images are often blended into one question. At this time, you need to clearly see the horizontal and vertical coordinates of each image, be familiar with the salient features of each image, summarize more, and avoid confusion. Oh. When you encounter a new image, analyze it slowly. The answer must be in the image~
Chemistry 7 Questions
In Chemistry, let me talk about the methods according to the question types. Because there are only these nine types of questions in the college entrance examination. If you are not good at any part, just practice the questions and summarize them by yourself, and ignore them. Just like my blog teacher said after taking the college entrance examination, you said I haven't talked about this question before. Changing the numbers is a question that has been taught before. So, chemistry is really very simple (don’t hit me...).
Chemistry and Life\Chinese ancient books lead to questions about matter: Chemistry and life are about accumulation. Generally, they are fragmentary things that are closely related to life mentioned by the teacher during lectures. Any small knowledge point can be Take the test. The titles in ancient Chinese books are generally relatively simple. Note that ancient technology was not as developed as it is now, and they basically used naturally occurring things: coal, oil, natural gas, etc.
Calculations related to NA and n: Needless to say this, just list the equations. Don’t be lazy. Once again, emphasize 22.4L, which has caused headaches for countless students. When summarizing the standard conditions for common exams, Be wary of liquid or solid substances!
Examination of basic organic knowledge: My common method for finding isomers is to start with the main chain and then branch chains, functional group position isomerism, and then isomerism. When it is time to consider cis-trans, consider cis-trans. . Different functional groups of two or more types are determined to move one. Basic organic knowledge is nothing more than molecular formulas, naming, reaction types, and reactions with characteristic substances. Mastering these is just a piece of cake, right?
Experimental operations, phenomena and conclusions\Experimental instruments: You must clearly remember the classic experiments in the book, and you must also be familiar with the situations and functions of each instrument. For example, the choice of reactor must be considered For solid-solid, solid-liquid, and liquid-liquid reaction types, the gas receiver must consider whether it is soluble in water, the density comparison with air, and whether impurities need to be removed, dried, and prevented from contaminating the air. We should also pay attention to some details. For example, the reaction rate of potassium permanganate and oxalic acid solution becomes faster first because of the catalytic effect of manganese ions.
Also, remember the most common pit to dig is to add barium chloride solution to a sodium carbonate solution containing phenolphthalein. The lighter color of the solution does not indicate any problem, because you are adding a solution and diluting it. So pay attention to the state of the added materials.
Element inference: Generally, unknown elements are inferred based on the number of electrons, valence, characteristic reactions, etc. The general questions are about the periodicity of elements. If you master this question, you will get points.
Judge whether the ionic equation is correct or incorrect: firstly, see whether the reaction can occur; secondly, see whether the reactants and products are correct; thirdly, see whether the separation of each substance is correct. Except for soluble salts of strong acids and strong alkali, other substances cannot be separated; fourthly, Check whether it conforms to the relationship of mass conservation and charge conservation. Five, check whether it is consistent with the original equation. Six, check "=", "?", "↑", "↓". (The order depends on personal preference~)
Electrochemistry: Positive and negative are the terms of the primary battery, and yang and yin are the terms of the electrolytic cell. When reading the question, first check whether there is a battery before writing. Let me give you some tips that I have summarized. You can also try to summarize your own memory methods. "Oxygen negative to positive" oxidation reaction is at the negative electrode, and reduction reaction is at the positive electrode; "positive positive and negative" positive ions move to the positive electrode, and negative ions move to the negative electrode; "positive oxygen negative to negative" anode oxidation reaction, cathode reduction reaction; Yin and Yang” cations move toward the cathode and anions move toward the anode. As for equation writing, standard definition valence, the environment determines everything. Be sure to pay attention to the solution environment, the components of the intermediate exchange membrane, whether there is water or not. If there is no water, only hydrogen ions and hydroxyl radicals can appear in the ions in the equation! It’s best to write in sections first and then write in total. To calculate the electron transfer number, how should I put it, it can be easily obtained by writing the equation. But pay attention to what you are asking and do not answer the question incorrectly. Regarding the issue of product acquisition, it is necessary to understand clearly the movement of ions through the exchange membrane, and which substance can be obtained by adding which substance.
Titration: Generally, it is the pH image of the titration process. When a certain amount is added, first find out the substances present in the solution at that moment, then deduce which ions are there, and then obtain the three conservation relationships of ions. Generally, they are strong acid and weak alkali salts or strong base and weak acid salts. Pay attention to the pH of the reaction at the right time, and it will be OK to compare the quantity and the degree of ionization and hydrolysis.
Precipitation problem of metal cations: Be sure to see clearly the horizontal and vertical coordinates, whether they are negative logarithms or logarithms! ! This is the ability to analyze images~
8 questions in physics
5 single-choice questions and 3 multiple-choice questions. Choose from multiple choices and choose the one that is most accurate. If you are not sure, don’t choose! ! When you have to draw a picture, draw a picture. If you are lazy, it will bring you a heavy price!
Draw the force analysis while reading the mechanics questions, list the equations of mechanical balance and Newton's second law, and you can see the increase or decrease of all forces. Energy-related questions require an analysis of energy changes, when and how energy is converted.
There is no essential difference between simple force questions about electric charges and mechanics questions, only the size of the force is different. As for the type of charge movement in the electric field, the direction of the force can be known based on the known trajectory. It is clear at a glance the direction of the electric field, the positive and negative charges, the level of the electric potential, and the acceleration.
As for the spaceship question, I have nothing to say. I wrote a few formulas and tinkered with it, and put in numerical values. No matter how difficult it was, the college entrance examination added an estimate.
For circuit questions, you must analyze the structure of the circuit before starting. Generally, it will be combined with alternating current. You must pay attention to the relationship between voltage ratio, current ratio, maximum value and effective value. Regarding the question of how the remainder changes when a certain change in the circuit occurs, my method is to first mark the required quantities U, U1, U2, I, I1, I2, etc. on the circuit, and then list the relationship between each quantity, from part to whole. When it comes to parts, if it is difficult to push ΔU\ΔI, look at the part that is complementary to this piece, because the entire circuit is stable, with increases and decreases.
Since the content of 3-5 has been added to this year’s compulsory exam, the multiple-choice question will inevitably have a multiple-choice question that replaces the original 35-choose 3-5 electives. Therefore, the basic knowledge of 3-5 cannot be ignored. Also make sure it is completely correct. After all, it is a compulsory exam. It is no longer a high probability to choose 3 out of 5. If you are not sure, you can still find the wrong one to choose or simply choose 3-4 elective questions. This question can only be correct and not wrong.
Examination of questions
Finally, the most important point in comprehensive science selection is the review of questions. Well, to be precise, this is the key point that is needed everywhere. Comprehensive science multiple-choice questions have high scores and high content. The questions must not be too simple. There will still be pitfalls. You must not be negligent when reviewing the questions. The words in brackets and charts are particularly important. Those will be your answers to the questions. key. Be sure to pay attention to things like "which of the following statements is correct according to...", "uses relative to properties", etc. Please enter text
Check the questions
Naturally, no matter how many methods are explained, you still need to do more questions, practice and explore by yourself. Gripping the questions is inevitable, and it does not matter how many questions you answer. What is something to be proud of? What is most important is that the questions you answer reflect their value.