Chemistry Review Methods. Help

Inorganic chemistry mainly looks at the properties and characteristics of common elements on the periodic table, understands that the properties of compounds are gradual, and then memorizes some special examples.

Organic chemistry is divided into three categories of alkylene according to 1. Hydrocarbons are divided into three categories of alkyne represented: methane, ethane, ethylene, acetylene.

Second, alcohols stand for: ethanol.

Third, aldehydes and ketones represent: formaldehyde, acetaldehyde, acetone.

Fourth, carboxylic acids represent: formic acid, acetic acid (acetic acid) and fatty acids.

As long as you follow the general characteristics of each category, you can master the questions of general difficulty.

In addition, when looking at the experiment, pay attention to the operation steps and the phenomena in the experiment, if you can use the rules to memorize, it is the best, if not, you also need some forced memory.

Take a notebook and systematically record the knowledge points that you think are very important, starting from the front, and pay attention to reading them often. Write down the knowledge points that are very easy to make mistakes in your usual exams from the reverse side, and copy the questions if necessary, review is very important, and it will be of great help to the total review in the future!

Find the question you did wrong before and do it again, correspond to the knowledge points, and check and fill in the gaps.

1. Chemistry mainly first understands the principles, then combines experimental phenomena and chemical equations, diligent memorization, and then combines some typical exercises to strengthen understanding and memory, and then pays attention to the comparison, induction and sorting of knowledge points. In fact, the questions are quite common, grasp the equations and various calculation formulas, and memorize the properties of various substances.

2. Preview before class. The day before class, be sure to take time to consciously preview what the teacher will talk about the next day. Learn to study first and then listen to the lectures.

3. Listen to every class. Listening to lectures is the core part of the learning process, and it is the main way to learn and master knowledge. Whether you can master the knowledge learned well in the classroom is the key to determining the learning effect.

If you can basically master the basic knowledge and skills you have learned in class, you will not have difficulty reviewing and doing homework after class.

4. Take good notes. To learn chemistry well, note-taking is also an important part. In addition to focusing one's attention and improving the efficiency of listening to lectures, note-taking is also a great help for post-class review.

So, learn to take notes and develop a good habit of taking notes. Therefore, while listening carefully, you should also take good notes.

5. Careful observation and hands-on experiments. Through demonstrations and student experiments, learning to observe the operation and phenomenon of the teacher's demonstration experiments, doing a good job in student experiments, and taking good laboratory classes are the foundation for learning chemistry well.

When I reviewed, I followed the teacher's steps, and after class, I strengthened my weak aspects, such as doing more questions in this area. It's better to do a few more composures.

Read the book first to familiarize yourself with the knowledge points.

Then do the questions, chemistry is science, and I rely on doing the questions.

The first....7m pcs....Because calcium carries a positive charge of two units....3m calcium ions require 6m of oxygen, oxygen, or chloride ions to counteract. m sodium ions need to be offset by equal hydroxide or chloride ions....A total of 7m is required

Question 2....The phone is not good, so I will use the computer to tell you when I get home....PS: Suppose ethane (C2H6 molecular weight 30) is a mol, alcohol vapor (C2H6O, molecular weight 46) is B mol, the mass fraction of oxygen is x=16b (30a+46b), the mass fraction of carbon is y=(24a+24b) (30a+46b), and the molecular weight of hydrogen is (6a+6b) (30a+46b)=y 4x+y+y 4=1

So y=4(1-x) 5

The second way to develop is because the molecular formula of ethane is C2H6 and the molecular formula of alcohol is C2H6O

After the oxygen is removed, the remaining molecular formula is C2H6

The mass fraction of carbon is 24 30 = 4 5

Then it can be seen that the mass fraction of carbon in the mixture is [4(100-x) 5]%, and the result is the same.

2*3m+m=7m

3x Analysis: This question tests the relationship between the relative molecular masses of the elements, and there are 4 elements c and 1 element o. 4c o

Problems like 3x x are often encountered in the future, and there is also the relationship between s o that is the most tested s=2o (o is the oxygen atom).

10m 3*3m+m=10mThe number of positive ions is the number of negative ions.

The hydrocarbon ratio is fixed, so the mass fraction ratio of hydrocarbon is also fixed, i.e. 12:1, so the answer is (1-x) 13

The total number of positive charges of cations in 7m wastewater: 3m 2+m = 7m

Each calcium ion carries two units of positive charge. The total number of negative charges carried by anions, chloride ions, and hydroxide ions is equal to the total number of positive charges carried by cations.

Problem 2 Solution: The mass ratio of hydrocarbon at the same point in two substances remains unchanged 12 2:1 6=4:1 If the total mass fraction of hydrocarbon is 1-x, then the mass fraction of carbon is 4(1-x) 5

Reading books, I have been telling my students that books are the foundation, but also the key, if you can understand the knowledge points and exercises in the books, then there is no problem with the exam, I used to read when I was studying, I generally did not do anything before the exam, I directly picked up the textbook and turned it page by page, to see where I don't understand, where I need to strengthen, basically I have to read the textbook twice or even three times, of course, there is no problem with the exam.

When reading the textbook, sometimes a whole chapter may be turned directly over, because you have completely understood, and if you don't understand, you have to read it well, slow down, and skip it when you understand it, and if you don't understand, you have to ask the teacher and ask your classmates, don't keep the questions in your head, then it will be very affected, and sometimes it may be because you have a knowledge point that is more vague and make other places you would have become uncertain, which will affect the results of the exam.

You turn from the first page of the book to the last page, usually there is a hook to draw the key points of the natural look carefully, equations, chemical formulas, formulas should be memorized, there is no skill at all.

So you have to remember it every day, especially in the morning and in the evening.

You are right, this situation is common in the early stage of the high school entrance examination. For the chemical part of science, now we have to review it as a whole, for the chemical formula, first use the valency and chemical formula to surprise out for a few hours, and then balance according to the law of conservation of mass.

First of all, you should remember the common chemical atomic relative quantities, because the chemical atomic weights commonly used in the exam will not be given to you, and it will be easy to calculate after memorizing. As for the balancing of chemical equations, according to the law of electron gain and loss and conservation of mass, it should be very simple! Electron gain and loss, in layman's terms, means that the electron gain and loss remains unchanged before and after a chemical reaction.

The law of conservation of mass means that the total mass of an element remains unchanged before and after a chemical reaction.

Usually read more books, look at more basic knowledge points, and then combine the topics to practice, so that the effect will be better!