1 ? Diligent in preview, good at listening to lectures and taking notes?
You must preview before class. In preview, besides reading the new lesson carefully, you should also mark the places you don't understand and try to do some exercises in the textbook. In this way, with questions and difficulties, the efficiency of attending classes will be greatly improved. And everyone should listen carefully? Taking notes carefully is not only conducive to reviewing after class and grasping the key points, but also can effectively prevent "mind wandering" in class. However, when taking notes, you should remember the key points, difficulties, doubts and contents that are not in the textbook on the basis of listening to what the teacher said clearly.
2 ? Review and do the test after class?
After the teacher finishes the class, he should review the knowledge points of the whole class in time, but the review should be targeted and avoid focusing on the key points. He should focus on reviewing the key points and main points in the teacher's lecture book. The purpose is to turn what you have learned into something in your mind, so that you can use it flexibly when you do the questions in the future. After reviewing, you should do some after-school exercises to find out your own shortcomings. In short, you should thoroughly understand the textbook. ?
3 ? How to create a wrong file?
Every time you finish the homework assigned by the teacher or the questions in the exercise book, you should record the wrong questions in the wrong book, and carefully analyze the reasons for the mistakes and the knowledge points involved in this question until the wrong questions are analyzed and understood, and you should draw inferences from one another and review them once in the weekend to minimize the chance of making mistakes again. ?
4 ? Classify and summarize knowledge points?
Chemistry is a subject with scattered knowledge points. When learning, we should classify and summarize the scattered and complicated knowledge, find out the internal relations and laws, and form a knowledge network. For example, the learned gases, such as hydrogen, oxygen and carbon dioxide, can combine their physical properties, chemical properties and how to make them and collect them, and compare them to remember them. ?
5 ? Memory learning?
We should focus on reading and remembering the main principles, laws and important conclusions and laws in textbooks. There are many basic concepts and principles in junior high school chemistry textbooks, which require more than 20 element symbols, as well as many chemical formulas and equations and other knowledge. These contents need to be memorized on the basis of understanding. They are mostly the basis of learning chemistry and must be memorized. If we sum them up and memorize them, we will get twice the result with half the effort. ?
6 ? How to learn chemistry experiment?
Chemistry is a subject based on experiments. We should carefully observe the teacher's demonstration experiments and do well in each grouping experiment. We must make clear and memorize the instruments, medicines, devices, experimental purposes, principles, steps, phenomena and matters needing attention. ?
(a) observation experiment should be combined with thinking? The observation of chemical experiments is generally carried out in the order of "before reaction → during reaction → after reaction". Observe and think positively at the same time. For example, when observing the phenomenon that copper and zinc are put into dilute sulfuric acid respectively, why can we see that zinc will produce gas when put into dilute sulfuric acid, but copper will not produce gas when put into dilute sulfuric acid? By thinking and sublimating perceptual knowledge, we will gain a deeper understanding that zinc is more active than hydrogen and can replace hydrogen from acid, while copper is not as active as hydrogen, so it cannot replace hydrogen in acid. ?
(2) Summarize the "one, two and three" in chemical experiment operation.
1. When taking solid powder in the laboratory, it should be "one inclined, two delivered and three vertical". Even if the test tube is tilted, carefully send the medicine spoon containing the medicine to the bottom of the test tube, and then erect the test tube to let all the medicine fall to the bottom of the test tube. ?
2. When using bulk solid or metal particles in the laboratory, it should be "one horizontal, two horizontal and three vertical". That is, put the container horizontally, put the medicine or metal particles into the mouth of the container, and then slowly erect the container, so that the medicine or metal particles slowly slide to the bottom of the container to avoid breaking the container. ?
3. In the liquid filtration operation, attention should be paid to "one stick, two low, three lean". One stick means that the filter paper clings to the inner wall of the funnel, the other is that the edge of the filter paper should be lower than the funnel mouth, the liquid level in the funnel should be lower than the edge of the filter paper, and the third stick means that the beaker should be close to the glass rod, the end of the glass rod should gently lean against one side of the three layers of filter paper, and the nozzle at the lower end of the funnel should be close to the inner wall of the beaker. ?
(3) Summarize the principle of fixation in the operation in the experiment?
1, the length should be distinguished (1). When washing gas, use a double-tube gas washing cylinder. The gas should enter from the long tube and exit from the short tube, that is, "long in and short out"; However, when measuring the volume of gas with a dual-tube gas cylinder, it should be "short in and long out" (2) The long-necked funnel should be inserted under the liquid surface through a rubber plug; When using the separating funnel, it should be inserted under the rubber plug for a short time, and it is not necessary to insert it into the liquid level. ?
2, the size should be distinguished (1) When weighing, first estimate the quality, and put the weights in order to enlarge first, then put the small ones, and then adjust the code. (2) The particles of the medicine packed in the drying tube should not be too small. If it is too small, the airflow will not be smooth, and if it is too large, the drying effect will not be good. (3) Solid drugs (powder or block) should be stored in wide-mouth (big mouth) reagent bottle, and liquid reagents should be placed in small-mouth (small mouth) reagent bottle. ?
3, up and down to distinguish (1) burette zero scale in the above, measuring cylinder small scale in the bottom. (2) During the liquid separation operation, the lower liquid should be discharged from the bottom by opening the cock, and the upper liquid should be poured out from the top of the liquid separation funnel. (3) There are upward air exhausting method and downward air exhausting method to collect gas. ?
4. The left and right sides should be distinguished (1). Use the tray balance to put the medicine on the left side and the weight on the right side, which is called "left object and right code". The scale of the roaming code is from left to right. When reading, read the scale on the left of the roaming code. (2) When adjusting the zero point of the balance, the balance nut should move to the left when the left side is light; When the right side is light, the balance nut moves to the right. (3) making gas, the making device is on the left, the collecting device is on the right, and the air flow direction is from left to right. (4) Place the test tube in the test tube rack from long to short and from left to right. (5) Assemble the instrument from low to high, and connect all parts into a whole from left to right. Disassembling the instrument is the opposite?
Seven? Thinking method of chemical problem solving?
1 multiple choice questions?
The commonly used methods to solve multiple-choice questions mainly include exclusion, direct election, inference, analysis and comparison, calculation and so on.
2 material inference questions?
The answer to the inference question mainly depends on its color, its state, its change, the first generation of test and the test. Mainly rely on their usual knowledge induction. For example, some special substances with colors: the solution containing Cu2+ is blue, the solution containing Fe3+ is brown, and the solution containing Fe2+ is light green. Inference questions have always been an important question in chemistry senior high school entrance examination, among which the most common ones are "narrative" inference questions, "experimental" inference questions and "block diagram" inference questions. For "narrative" inference questions, it is generally "step by step", and it is not difficult to solve such questions by combining them with problems. The "experimental" inference questions are mainly combined with the basic operation and identification methods of experiments, which are comprehensive and examine the basic operation of students' experiments and chemical knowledge.
3 calculation questions?
The following three knowledge points are generally used to solve calculation problems: law of conservation of mass, chemical equation and commonly used calculation formula. There are many types of junior high school chemistry calculation problems, including chemical formula calculation, valence calculation, chemical equation calculation, solution calculation, simple comprehensive calculation of chemical equation and solution, and calculation by applying the law of conservation of mass. The general steps are as follows:
1 Set unknown quantity 2 and list chemical equation 3. Write the relative molecular mass of related substances, known quantity and unknown quantity 4 and list the proportional formula to solve.