That one will help me do this set of 30

Brothers: How many classes? The answer is to share the sprinkle!

Mathematics problems must be done accurately by yourself, so the learning of mathematics must rely on yourself, and the best learning methods are as follows.

So, what are the learning methods?

1. Preview. Preview is a very important learning method, through the preview, you can be familiar with the content and structure of the article, in the process of preview, you can mark the place you don't understand, so that when you go to class, you can take the questions, so that you can listen to the class in a targeted manner, and then improve the interest and efficiency of learning.

2. Take notes during lectures.

Listening to lectures is an important way for people to receive information. In the process of listening to the lecture, people can learn most of the content, so it is very important to grasp the lecture well. Be sure to concentrate, listen to the teacher, take notes, participate in class activities, and actively ask questions.

3. Do your homework carefully.

After the lesson, the teacher will give the students homework. The purpose of the assignment is to further consolidate what has been learned in class. So, be sure to take your homework seriously.

4. Review and summary.

After learning, you must review and summarize, through review and summary, you can make the learned content into your own knowledge, and in the review and summary, find new problems, and further deepen your understanding of the knowledge points.

5. Maintain self-confidence.

Self-confidence can bring great motivation to people, and only with self-confidence can we make every day more energetic and better remember what we have learned.

1, False 22, False 23, True 24, True 25, False 26, True 27, False 28, True 29, True 30, True 31, True 32, False 33, False 34, True 35, True 36, False (should be open thinking, those three also have a part) 37, False 38, False (I personally think that oral communication is to make everyone more courageous, confident, and more proficient in language expression) 39, False 40, True.

Think for yourself, things are done with your hands, I hope you can figure it out. The answers to the workbook are in the text, and that's all I can tell you. Read carefully, carefully taste. ok?

"Hello, happy to answer your questions!" 【Answer】C Analysis: The state is a tool for the ruling class to rule by class, and the cultural ideas it promotes should be conducive to the ruling class to carry out class rule. Hence the dominance.

1 Concentration of substance: The amount of solute contained in a unit volume solution Unit: mol l

2, short answer 1 Salt spraying on the road surface can reduce the freezing point of water, thereby preventing freezing.

Fill in the blank 1 Glucose is a non-electrolyte, NAAC and BASO4 are strong electrolytes, HAC is a weak electrolyte, and BASO4 is a strong electrolyte that is difficult to dissolve.

The conjugated acid of 2H2O is H3O and the conjugate base of H2O is OH.

4 Buffer solution: HAC Naac, NH3H2O NH4Cl

5 Properties of buffer solution: The rate of change of pH is very small when acid and base are applied.

6. Add sodium acetate to the acetic acid solution, at this time, the ionization degree will become smaller, and the ionization constant ka of acetic acid will not change.

7.The relationship between the conjugated acid-base pairs between ka and kb is : ka kb kw

8.Ion product QC9The concentration is a mixed solution of Cl-, Br-, and I-, all of which are mol L-1, and Agno3 solution is added dropwise, and the precipitate sequence is I-, Br-, and Cl-

The first short-answer question upstairs did not answer the main point, in the rain, snow and freezing weather, often sprinkle salt on the road surface to prevent the road from freezing, and the question requires that the acid-base balance and precipitation dissolution balance knowledge explain the reason, ·· Also, the buffer pair of question 4 is not written like this, it is not standardized... Everything else is correct.

To be honest, these are very basic, find the answers in the book, except for the lower 2 questions, the calculation questions are the original questions in the book to change the data (such as the ka of HAC, the data in the book is the ka of HAC.

Let's look for it in the book.

40/(1+20%)=a%=a

40/(1-20%)=b%=b

40-a=c(yuan). Earn.

b-40=d(yuan)。。 Lose.

d-c=f(yuan)。。 After neutralization, it is the total profit and loss ratio (it should be a loss, but I didn't have time to calculate, you better calculate it again, and the calculation is roughly like this.) Because I'm a primary school student, I encountered this kind of question a few days ago, but the condition is that both shirts are 60 yuan, I studied it and made it, and it's a little different from your question, but it should be right).

Find the original price 48 (1+20%)=40

48 + 48 < 40 + 60, so the loss is 40 + 60 - (48 + 48) = 4 yuan.

Let the original price of the two pieces be x1 x2 respectively, then there is: x1 x2 so x1+x2=

$100 The answer is a loss of $4.

48 divided by 1-20% = 60 48 divided by 1 + 20% = 40 40 + 60 = 100 48 + 48 = 96 96 less than 100 100-96 = 4 A Profit Profit 4 yuan.