Do you have any chemistry and physics knowledge that is particularly easy to understand? Please!!!!!

1.The production and propagation of sound.

1) Sound source: The object that vibrates and emits sound is called the sound source.

Sound is produced due to the vibration of an object. Everything that is making sound vibrates; As long as an object vibrates, it will make a sound, but this sound may not be audible to the human ear.

2) The sound emitted by the vibration of the sound source needs to have a medium to propagate. The medium can be a variety of different solids, liquids, and gases.

No sound can be transmitted in a vacuum.

3) Speed of sound: The speed at which sound travels is called the speed of sound. Sound generally travels at different speeds in different media. In general, sound travels the slowest in gases and fastest in solids.

In addition to this, the speed of sound is also related to temperature, and even in the same medium, the speed of sound is not the same under different temperature conditions.

4) Echo: When the sound travels in the air, if it encounters a tall obstacle, it will be reflected back by the obstacle to form an echo. For the human ear to be able to distinguish between acoustic and echo sounds, the interval must be more than a second.

This means that an echo that the human ear hears only seconds after it hears the original sound can be clearly distinguished, but if it is within a second, it cannot distinguish between an original sound and an echo.

Echo has many important applications, such as measuring the depth of water and measuring the distance of tall buildings.

2.There are three characteristics of musical sound.

1) Pitch: The pitch of the voice is called pitch. It is determined by the frequency of the emitter's vibrations. The faster the emitter vibrates, i.e., the greater the frequency, the higher the pitch, and the slower the emitter vibrates, i.e., the smaller the frequency, the lower the pitch.

2) Loudness: The magnitude of the sound perceived by the human ear is called loudness.

Loudness is related to the amplitude of the emitter, the greater the amplitude, the louderness, the smaller the amplitude, the smaller the loudness. In addition to this, loudness is also related to the distance from the emitter.

3) Timbre. It is determined by the emitter itself, which is the quality of the sound. Depending on the timbre, we can distinguish between what instrument is producing the sound or what other sound source is producing the sound.

For example, the color of fireworks is different, because the metal contained in it is different, and the metal burns in different colors. When sodium nitrate is added to the sodium-metal compound, the fireworks appear yellow, strontium nitrate produces red, copper nitrate produces blue, and barium nitrate produces green ......The dazzling white light comes from metal powders such as magnesium and aluminum.

Physics: Small-hole imaging. Use a plate with a small hole to block between the screen and the object, and the inverted image of the object will be formed on the screen, which we call this phenomenon small hole imaging. Remember to be upside down.

I don't know what you mean, but there are a lot of physical chemistry books in junior high school.

Too much! I don't know what the landlord is talking about! If you need to, you can ask me!

Hello, lijiuxuya

lgk= that is, k=10

As a side note, 10 can be calculated with a calculator so that the value of k can be obtained.

It means that with 10 as the base, the power of 10 can be equal to the k-power.

If I remember correctly, I can only calculate it with a calculator or a look-up table, and the written calculation has to go through complicated trial calculations, which is very troublesome.

k is equal to the ratio of the coefficient power of the concentration at the equilibrium of the product to the power of the coefficient of the concentration at the equilibrium of the reactant.

k chemical equilibrium constant, generally related to temperature, the attached table will list the equilibrium constant values at different temperatures**, you can find it according to this table.

Add the reaction equation aa+bb=cc+dd, then the equilibrium constant k is =[c] c[d] d [a] a[b] b

For general reversible reactions.

AA+BB*****=Reversible==== gg+hh equilibrium.

k=( (g)＾g * h)＾h )/( (a)＾a * b)＾b )

where (g)(h), etc., denotes the concentration of substances g and h k is the equilibrium constant.

Above: At a certain temperature, when the reversible reaction reaches equilibrium, the ratio of the product of the power of the concentration of the product to the power of the concentration of the reactant is a constant, and the power index is the stoichiometric number.

Change the temperature and the value of k will change.

According to the thermodynamic relationship:

rtlnk = g (for superscript).

Since, for a particular reaction, the standard free energy change g is only a function of temperature, the equilibrium constant k is also only a function of temperature t, i.e., k is only related to temperature t.

Hopefully, these can give you some inspiration.

The answer can be drawn from both sides to the tenth power at the same time!! It's just one way, we can think of something else.

AA+BB reversible sign CC+DD,A,B,C,D, respectively, the coefficients of a,b,c,d in this reaction.

Then it can be derived knowing the equilibrium concentration of the reaction.

k = (c(c(c) to the power of c multiplied by c(d) to the power of d) (c(a) to the power of a multiplied by c(b) to the power of b).

That's not the power of direct e to come out.。。。

It depends on how far you want to learn.

If you only learn some basics, then I think physics is more practical, and the knowledge that middle school students learn is more basic and simple. The basics of physics are still useful in real life. Chemistry is okay, but I think the physics aspect, especially electricity, is useful for everyday life.

If you want to learn a little deeper, then chemistry is a little better than physics, chemistry has applications in many industries, and advanced physics tends to be a research-oriented discipline, and only those who are committed to research will be exposed to advanced physics.

So which is more practical for physics or chemistry depends entirely on your own situation.

Each has its own use, and it doesn't matter which one is more useful;

If you talk about the contribution to the college entrance examination scores, the proportion of their scores should be the same.

Physics: Prerequisite: Learn mathematics first. Because mathematics is the foundation and tool of physics.

First, memorize the definitions, laws, theorems, and laws in physics.

Second, clarify the relationship between physics knowledge.

Third: do more questions, practice makes perfect.

Fourth: Do comprehensive questions.

Fifth, experiments are a very important part of learning physics, which can deepen our understanding of physics knowledge and cultivate our ability.

Chemistry: Prerequisite: Learn math first. Because mathematics is the foundation and tool of chemistry.

First, memorize the definitions, laws, theorems, and laws in chemistry.

Second, clarify the relationship between chemical knowledge.

Third: do more questions, practice makes perfect.

Fourth: Do comprehensive questions.

Fifth, experiments are a very important part of learning physics, which can deepen our understanding of chemistry knowledge and cultivate our ability.

Listen carefully in class and practice more after class.

Mathematics: Theorems in textbooks, you can try to reason on your own. This will not only improve your proof ability, but also deepen your understanding of the formula.

There are also a lot of practice questions. Basically, after each class, you have to do the questions of the after-class exercises (excluding the teacher's homework). The improvement of mathematics scores and the mastery of mathematical methods are inseparable from the good study habits of students

Listening, reading, **, homework Listening: should grasp the main contradictions and problems in the lecture, think synchronously with the teacher's explanation as much as possible when listening to the lecture, and take notes if necessary After each class, you should think deeply about it and summarize it, so that you can get one lesson and one lesson Reading: When reading, you should carefully scrutinize, understand and understand every concept, theorem and law, and learn together with similar reference books for example problems, learn from others, increase knowledge, and develop thinking **:

To learn to think about the side of the test, after the problem is solved, and then explore some new methods, learn to think about the problem from different angles, and even change the conditions or conclusions to find new problems, after a period of study, you should sort out your own ideas, in order to form your own thinking rules Homework: to review before homework, think first and then start writing, do a class of questions to understand a large piece, homework to be serious, writing to standardize, only in this way down-to-earth, step by step, in order to learn mathematics well In short, in the process of learning mathematics, It is necessary to realize the importance of mathematics, give full play to one's subjective initiative, pay attention to small details, develop good mathematics learning habits, and then cultivate the ability to think, analyze and solve problems, and finally learn mathematics well

Chemistry: Mainly to memorize some properties, write equations, etc. Textual things, you can take a look at it and memorize it.

The key to theoretical things is to understand, and if you understand it, you will be able to draw inferences from one another. For example, in a chemical equation, in order to write a correct chemical equation, you must first write the chemical formula of each reactant and product, and in order to write the correct chemical formula, you must understand the valency. If you just rely on rote memorization, it is still easy to forget when it comes to the exam, and understanding is the most important thing.

So you have to memorize more practice questions, such as multiple-choice questions, the teacher gives you some special properties to choose, so more practice can invisibly help you remember. The effect of light memory is not good. The more you practice the nature of those special substances, the more you will remember.

The big topic is reasoning, writing equations, and with a good foundation, you will not be afraid.

Physics: Mainly the understanding of concepts and formulas. For concepts, you must grasp them well, and doing more multiple-choice questions will help you grasp the understanding of concepts.

But you must take each question seriously and understand each option when you do it. Calculation questions are accurate formulas. So be especially aware of the meaning of the formula.

Practice more, the questions are actually many similar.

In short, it is a process of accumulation, the more you know, the better you learn, the more you memorize, and choose your own method. Good luck with your studies!

Persistence is required, and only those with perseverance will succeed.

Understand the basic concepts, and familiarize yourself with the origins of each concept and the connections between them.

It is necessary to do some questions independently, with quality and quantity. There should be a certain number of questions, not too many, not too few, but also a certain quality, that is, a certain degree of difficulty. Anyone who learns mathematics, physics and chemistry will not be able to learn well without going through this level.

Solving problems independently, sometimes too early, sometimes slower, sometimes detours, sometimes even unable to solve them, but these are normal and the only way for any beginner to succeed.

It is necessary to be clear about the physical process, and there is inevitably a hidden danger of solving the problem if the physical process is not clear. Regardless of the difficulty of the topic, you should draw as much as possible, some sketches are sufficient, and some should be precise to show the geometric relationship. Drawing can transform abstract thinking into figurative thinking and grasp physical processes more precisely.

With graphs, state analysis is fixed, dead, and intermittent, while dynamic analysis is alive and continuous.

Study materials should be well preserved, classified, and marked. The study materials are categorized into practice questions, test papers, lab reports, and more. Marking means, for example, for practice questions, general questions are not marked, good questions, valuable questions, and easy to make mistakes are marked differently, so as to be ready for future reading, and marking can save a lot of time.

It is necessary to attach importance to the knowledge structure and systematically grasp the knowledge structure, so that the scattered knowledge can be systematized. It is as large as the knowledge structure of the whole physics, as small as the knowledge structure of mechanics, and even down to the chapters, such as the knowledge structure of statics, and so on.

Junior high school or high school First of all, you should subconsciously think that physical chemistry is difficult, which will increase your learning obstacles Secondly, it is the basic knowledge Start with simple questions So that your correct rate will be very high, and it will also increase your confidence in learning The basic knowledge is good The rest is not a problem In addition, you should listen carefully to the teacher's lecture in class, and it is very important to listen to the lecture honestly and honestly Finally, you will do more Lu pretend practice questions From the questions, you will find that your mastery of knowledge points.

Science is first of all comprehension, followed by constant repetition of practice, practice makes perfect can not be wrong!!

This seems to be a comprehensive exam question.

1）nh4no3

2) 4NH4NO3 = high temperature = 2NH2 +3N2 +8H2O

bTake a look at this chemical equation.

The calcium chloride produced by the reaction of Ca(OH)2+2HCl=CaCl2+2H2O is slightly soluble in water and can produce precipitation in the stomach. And calcium hydroxide is alkaline and corrosive. There is some harm to the body.

**Excessive gastric acid is generally used with barium carbonate, and the substances formed by the reaction are water and barium chloride, and barium chloride is soluble in water.

b**Excessive gastric acid generally does not choose alkali, but selects strong alkali and weak salt.

Ca(OH)2 is a strong alkali, alkaline than sodium hydroxide, and cannot be used for excessive gastric acid. One is because when the stomach passes through the esophagus, it will cause damage to the esophagus and mouth, the second is that the amount of food is not easy to control, and the third is that it is estimated that this thing is not delicious