Chemical headaches, chemical headaches, ask for answers

First of all, you must be familiar with the textbook, because the things in the textbook are the most basic.

Secondly, you should take notes carefully, and every word the teacher says must be very clear.

The knowledge of chemistry is very trivial, and it is much more memorized

First of all, we must get the foundation right, and we must be familiar with what we should memorize, and it is not a problem to have basic questions and tactics.

When I was in my third year of high school, the teacher always had to shout us twice before class--- the questions we did would be done, and the questions we missed were good. The chemistry questions in high school are not finished, the key is to understand the essence of each question, and after completing each question, whether it is right or wrong, you must slowly go through it in your mind like a movie. Of course, the foundation is very important, chemistry is a liberal arts in the sciences, in addition to listening carefully in class, you must continue to accumulate some trivial things.

Record the good deeds and read them 10 times a day before going to bed, and the effect is very good.

In fact, it is still a sea tactic. However, it is also necessary to understand, and you can't just do it. Chemistry in high school also requires a foundation in mathematics and physics.

Chemistry is a liberal arts subject in the sciences that requires both understanding and memorization, and you are familiar with the physical and chemical properties of each substance. If you want to improve your chemistry score, the question is the key, and memorization is the premise.

1. Foundation: Foundation: The foundation is the most important foundation, and lay a solid foundation.

2. Textbook-based, especially chemistry books, should be read.

Remember more and summarize more.

3. The inorganic basic method is to keep in mind the three major conservation skills.

4. There are several lines and the relationship between them.

5. Nothing else is difficult.

Chemistry is a partial subject, and it is not difficult to study it seriously.

1.The language of chemistry is equations, and you must memorize them all, just like English words. You can't learn chemistry well without equations.

2.The physical properties and chemical properties of important substances learned in class should be organized in an orderly manner and accurately recorded.

3.Chemistry is a bit tedious but not difficult. It's mostly memorization, and a notebook will help you a lot.

4.If you practice more questions, you'll be fine.

Contains sulfuric acid: ,.

Concentrated sulfuric acid: 25g.

1.The required volume of concentrated H2SO4 is.

2。If the laboratory has a 10ml 20ml 50ml graduated cylinder, 20ml is the best.

3.The measured concentrated H2SO4 is slowly injected into a beaker with about 100ml of water along the inner wall of the beaker, and stirred continuously to accelerate the dissolution and make the heat released by the sulfuric acid dissolved in water spread evenly, so as to prevent local overheating and liquid boiling.

4.Inject the above solution, cooled to room temperature, into a 500 ml volumetric flask along a glass rod and wash the beaker 2 3 times with 50 ml of distilled water, the washing solution should be transferred to the volumetric flask, and shake well.

5.Add water to a distance of 2 3cm from the scale, and use a rubber tip dropper to add water, so that the concave surface of the solution is just tangent to the scale mark.

1. The molecular weight of H2SO4 is 98,500ml, and the mass is set to a volume to obtain a=

The ml volume range is large, and the required sulfuric acid solution can be obtained at one time, which is more accurate than 50ml.

3. Prevent sulfuric acid from splashing out, release heat during dilution, stir to dissipate heat evenly, and evenly absorb heat from the solution.

4. Cooling, glass rods, volumetric flasks, and injection volumetric flasks.

5. At the following 2-3cm, the rubber head dropper drops.