I need first aid chemistry!! High School Chemistry, First Aid!

Whether you are good in the exam only means now, not in the future, as long as you study hard, you can learn well.

There is no doubt that chemistry is a science, so learning chemistry requires understanding and application.

When you're just starting out in chemistry, what you should do is be familiar. Whether it's chemical formulas, element symbols, etc., you need to practice writing. That is to say, as long as it is in the book, you must remember that the teacher is ripe! This is the most basic!

Secondly, good chemistry requires understanding and memorization! No rote memorization! If you memorize by rote, even if you can pass the knowledge points, you won't be able to take the exam. So, you have to figure out everything you've learned!

Remember, chemistry must not allow for a little sloppiness!!

Let me tell you how I studied chemistry, 1) I have to memorize everything that is in the book or added by the teacher. (Understanding Memory!) 2) One chemistry exam question every day. (I'm still a junior high school student, hehe) 3) Prepare for it seriously.

4) Multi-Extension! Even if the teacher didn't ask me to memorize it, as long as I met it, I would hit it a few times. This way, even if it is not very useful now, it will always be useful.

So. To sum up, it is to study hard and expand a lot.

good luck！

I am a chemistry teacher in high school.

In fact, chemistry is very simple, the key lies in your implementation, I believe that after you pass this exam, you will work hard to change the status quo in the future.

First of all, you have to listen to the lecture well, let you do the post-class questions, and finally add some practice.

It's not a shame, it may be like this when you just start learning, it may be that your learning method is wrong, or whether your interest in chemistry is high, you need to be interested in learning anything, if not, it's good to learn nothing and not go back! Keep it up.

Negative electrode reaction: Pb + SO42- -2E == PBSO4 The negative electrode is converted from PB to PBo4 (solid, deposited on the negative electrode), so the mass increases.

Positive reaction: PBO2 + SO42- +4H+ +2E ==PBSo4 + 2H2O

The cathode changes from PBO2 to PBSO4, so the mass of the cathode also increases.

Hello 92 180=51mmol dl

1dl = so 51mmol dl = 5,1mmol l so is normal.

<> is like a cavity to celebrate Wu Feng and clear it.

Mobile phone loans do not require face recognition.

CO is generated as a reducing agent to reduce iron from the ore.

Fe2O3+3Co=2Fe+3CO2, assuming that 160---2x56 tons of pig iron are obtained

4900x76%--wx98%, w=2660 tons.

There is element C and element H in the product, and the substance must have C, H may have OCO2---C and carbon conservation 44g 12

h2o---2h conservation of hydrogen 18 2

The remaining mass is = conservation of mass.

then this mass must be of the O element.

The answer is d The remaining step: c:h:

o atomic ratio = (:(

6:1: The substance is C2H6O, which cannot be C4H6O2 (computational chemical bond), and may be CH3CH2OH ethanol or CH3OC3 methyl ether.

The carbon content in the selected carbon dioxide is (12 44)*

The hydrogen content in the water is (2 18)*

There are a total of 3g of carbon and hydrogen, which cannot reach the burning substance, so there is still oxygen in the original substance.

The C h element in which it is produced is the weight provided by a substance.

What is it? It can only be o-ro.

1) The ionic product constant kw = 10 -12 of water at this temperature(The ionic product constant of water is not always 10 -14, it is related to temperature).

2) The exact value of the concentration of the substance of the NaOH solution is 10-B mol L(i.e. OH-concentration).

3) At this temperature, after mixing 100 ml of mol l of dilute sulfuric acid with 100 ml of mol l of NaOH solution, the pH of the solution = the volume after mixing becomes 200 ml, NaOH is excessive, and the concentration of OH in the solution is, pH = 14-(

Because A is the most produced metal in the world, A is Fe

From the yellow-green gas, B is Cl2

Guess: Generally, chlorine gas reacts with colorless gas, which is generally H2 or NH3, and because it can react with A-Fe.

Therefore, C is H2 and C is formed after the reaction

Therefore f is FeCl2

The oxidation of FeCl2 by chlorine to FeCl3 confirms the previous series of speculations.

Therefore: a: fe

b：cl2c：h2

Reaction : 2Fe + 3Cl2 = (Heating) 2FeCl3 Reaction Equation: H2 + Cl2 = (Ignition) 2HCl Reaction Ion Equation: 2 (Fe2+) + Cl2 = 2 (Fe3+) + 2 (Cl-).

Note: Reaction conditions are in parentheses.

Note: The reaction is not an ionic reaction (is the title correct?) ）

The first one is empty, 0, and the second is empty.

Analysis: In this reaction, the chemical valence of copper sulfate before and after the reaction did not change, so copper sulfate oxidized from time to time and could not oxidize phosphorus.

Before and after the reaction, the valency of phosphorus increases and decreases, so phosphorus is both an oxidant and a reducing agent. Calcium phosphide is a reduction product, and phosphoric acid is an oxidation product.

Among the 11 parts of phosphorus, 5 parts of phosphorus are oxidants, 6 parts of phosphorus are reducing agents, 5 mol of phosphorus can oxidize 6 mol of phosphorus, so 1 mol of phosphorus can oxidize phosphorus.

If you ask this question: how many moles of phosphorus are oxidized when 1mol of copper sulfate reacts. The answer is because 15mol of copper sulfate participates in the reaction, and 6mol of phosphorus is oxidized.