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Hello dear. If this is a high school question, then you can find it.

If it's a junior high school question, then you can find cu-zn

According to **, the third time, the Zn reaction is completed, and the mass of Zn can be found according to the mass of all hydrogen, so as to find the mass fraction of Cu.

I hope you don't understand, please ask, thank you.

It should have been 5 moles just made a mistake, sorry.

First, 1 mole of chlorine C2H4Cl2 is consumed during the addition process

Because only hydrogen atoms with substituents replace chlorine atoms, it is understandable that when the amount of chlorine consumed is maximum, the hydrogen atoms required are completely replaced.

The reaction of the substituted 1 h atom that is substituted for each mole of chlorine to generate new organic compounds and HCl, because there are 4 h atoms substituted for the reaction requires 4 moles of chlorine to replace the chlorine in the maximum amount of 4 moles of the reaction consumes 4 moles.

The reaction exchanges chlorine substances up to 1 + 4 = 5 moles.

In the case that 2 bromobenzene cannot, the simple elimination reaction can be used as some other reaction steps.

The bromobenzene elimination products and other reactive intermediates such as phenylacetylene C6H4, which cannot be stabilized by a single machine, will occur immediately.

The university also has an intermediate reaction mechanism such as benzyne, and if you are interested, you can take a look at the organic of the university.

Because dilute hydrochloric acid only reacts with zinc, so only the mass fraction of copper in the copper-zinc alloy can be measured, from the experimental data, 10 grams of alloy powder are collected in total, and 1molH2 corresponds to 1molZN from the reaction relation, so it can be known that 10 grams of alloy powder contains zinc, that is, grams, so the mass fraction of copper in the alloy is (

（1）ph=9

c(h+)=10^-9mol/l

C(oh-)=10-5 is ultimately an alkaline solution, so so much H+ is water-ionized.

According to h2o=h++oh-

So H+ ionized by water and oh- ionized by water are equal (note that ionization by water or ionization of acid-base is different). So the OH- concentration of water ionization is 10 -9mol LThe answer is wrong.

2) Charge conservation relation. c（na+）+c（h+）=c（a-）+c(oh-)

It becomes under the move.

c（na+）-c（a-）=c(oh-)

c（h+）=10^-5

The concentration of silver nitrate is greater than that of potassium chloride, and the excess of AgNO3 is mixed in the same volume, and the generated AGCL nuclei adsorb AG+, making the gel particles positively charged [(AGCL).].Xno3-, polypreponderant colloidal particles with a positively charged sol, the greater the negative ion valence in the added electrolyte, the stronger the poly-sinking ability, the strongest sodium phosphate, the weakest aluminum chloride, said that the concentration of potassium chloride is greater than that of silver nitrate, [(AGCL), negatively charged, it is the positive ion that plays the role of poly-sedimentation, the larger the positive ion valence, the stronger the poly-sinking ability, the strongest aluminum chloride, and the weakest sodium phosphate.

Can't find it.

Because you don't know the density of 98% sulfuric acid, you can't find the original mass, but if you don't just do the question, you can check the density of 98% sulfuric acid, so the original mass is 10*

Then it contains sulfuric acid 18*98%=

Then 100g of water is added, and the total mass becomes 118g, so the mass fraction is.

There is no answer to this question.

Because the density of 98% sulfuric acid is not given, and the density is not given after dilution to 100 ml, it is not counted.

The solute mass before and after dilution remains unchanged, and the mass fraction is x.

10*98=100*xx=