Junior high school chemistry, the master is coming, and the junior high school chemistry master is c

1. The smell of burnt feathers.

It shows that it contains protein, and the first two are chemical clothing, and the third one does not contain protein, only wool contains protein.

2. Use salt to melt the ice and snow on the road.

Clause. One or three must not be reduced.

The second one is purely for the sake of making up the numbers.

The fourth one could be bulldozered, and the salt should be turned into ice to lower the melting point - it would be D anyway.

P.S. A few upstairs are purely misguided children.

I'm a sophomore in chemistry.

Wool is a biological hair that, like humans, contains protein.

The method of exclusion is the same as on the second floor.

Choose D for both, it's very simple, wool fibers and human hair are protein fibers, so they have that taste when burned.

Second, NaOH uses the NA ions in the gaffe, so the salt is reduced.

Don't listen to the nonsense on the first floor.

I am a fourth-year graduate in the textile industry.

On the 1st floor, I'm so angry!

Of course it's d, d pulled!

Details have already been explained by others.

I'm just going to scold the !! who went down to the 1st floor.

Both choose c, the first should be fiber, or burn it to try, and the second one reduces the use of industry, hehe.

Just graduated from high school and all of them were burnt feather-smelling proteins.

By the way, ask what does burnt feathers taste like.

1D 2D halo, the college entrance examination has just ended, hehe!

d, d is something on the top of the building, misleading people's children.

There must be copper sulfate, sodium oxide, must be barium chloride free, and possibly potassium nitrate.

From the first step, there is a blue precipitate generated by adding water, and it can be seen that the blue precipitate is copper hydroxide, so there must be copper sulfate and sodium oxide.

In the second step, nitric acid is added, and the acidified barium nitrate has a white precipitate to form, which further indicates that there are sulfate ions in the solution.

The third step is to add nitric acid, acidify the silver nitrate without precipitation, and it is known that the solution does not contain chloride ions.

None of the above phenomena can prove whether the solution contains nitrate, so potassium nitrate is uncertain.

Equation 1 Na2O+H2O=2NaOH

CuSO4+2NaOH=Cu(OH)2 +Na2SO42 CuSO4+BA(NO3)2=BaSO4 +Cu(NO3)2Sodium oxide can also react with water to form sodium hydroxide.

Uncle is a senior in high school, can it......I guess it's sodium peroxide.

There is CuSO4 sodium oxide.

Must be barium chloride-free.

May contain potassium nitrate.

Blue precipitated copper hydroxide requires copper ions and hydroxide hydroxide from sodium peroxide plus water white precipitated barium sulfate.

There is no precipitation after acidification, so there is no silver chloride.

1 2na2o2+2h2o=4naoh+o2↑cuso4+2naoh=cu(oh)2+na2so42 cuso4+ba(no3)2=baso4↓+cu(no3) 2

The solid must contain copper sulfate and sodium oxide; Must not contain barium chloride and may contain potassium nitrate

1. Na2O+H2O=2NaOH CuSO4+NaOH=CuOH (precipitation) + Na2SO4

2. Na2SO4 + BA (NO3) 2 = BASO4 (precipitation) + 2nano3

CuSO4 + BA(NO3)2 = BASO4 (precipitate) + Cu(NO3)2 (if the copper sulfate is not reactive).

The inner wall of the reagent bottle of clarified lime water stored for a long time is often hung with white solid attachments, and the white solid is changed.

It is calcium carbonate caCO3.

What is the equation that generates this?

Ca(OH)2+CO2=CaCO3 +H2O ion equation is?

Ca2+ +2Oh- +CO2=CaCO3 +H2O The white solid can be washed off with (dilute HCl hydrochloride), and the ion equation is?

caco3+2hcl=cacl2+co2↑+h2o

Calcium carbonate Lime water reacts with carbon dioxide in the air to form calcium carbonate, and the equation is:

ca(oh)2+co2==caco3↓+h2o