The problem of scheme selection in chemistry and what is the principle of chemical crystallization m

Copper oxide, iron, dilute sulfuric acid, three substances, two different schemes are designed to make copper.

The first type: cuo+h2so4=cuso4+h2ofe+cuso4=feso4+cu

The second type: Fe H2SO4 FeSO4 + H2H2 + Cuo = Cu + H2O (the condition is heating).

The iron oxide in the above question should be copper oxide.

Scheme 1: Fe+H2SO4=FeSo4+H2 H2+CuO=Cu+ H2O

Solution 2: Cuo + H2SO4 = CuSO4 + H2OFE+ CuSO4 = FeSO4 + Cu

Did you make a mistake in your title? There's no copper! Use copper oxide, iron, dilute sulfuric acid, three substances, design two different schemes to make copper, that's it! The first type:

fe＋h2so4＝feso4+h2

H2+Cuo=Cu+H2O (condition is heating) Type 2:

cuo+h2so4=cuso4+h2o

fe+cuso4=feso4+cu

Unless nuclear fission occurs, it should not be possible.

It's copper oxide.

The first method.

Dilute sulfuric acid and copper oxide react to form copper sulfate and water.

h2so4+cuo--cuso4+h2o

Iron and copper sulphate react to form ferric sulphate and elemental copper.

fe+cuso4--feso4+cu

The second method.

Iron and dilute sulfuric acid react to form iron sulfate and hydrogen.

Fe+H2SO4--FeSO4+H2 (standard gas rising symbol) can be heated and reacted with the generated hydrogen and copper oxide to form elemental copper.

h2+cuo--cu+h2o

There may be toxic gases such as CO2, CO, H2S, etc., which are caused by the mass multiplication of aerobic bacteria in the organic environment, the method is the same as above, but if it has been poisoned in the well, it should be taken away from the site immediately and placed in a place with sufficient oxygen and smooth air circulation, and artificial respiration or assisted respiration should be carried out according to the situation.

The method of putting small animals on the first floor is somewhat inhumane and strongly refuses to be used!!

It is caused by the accumulation of a large amount of carbon dioxide, so you can take a lit candle and put it in to see if it goes out, or put a small animal (chicken, rabbit) in it to see if it is poisoned.

Hanging in a sunny, ventilated and dry place, principle: accelerate the diffusion of molecules, the low saturation of water molecules in the air is conducive to the outward diffusion of water molecules in clothes.

Or dry it in a dry place with a hair dryer, the principle is the same as above.

Dry warmly with an iron, principle: give energy to the water molecule, so that he can quickly transform the material form.

What are the methods that can be taken to make wet clothes dry faster?

A: Drying wet clothes in the sun or in a ventilated place can make the clothes dry faster The higher the analysis temperature, the faster the molecules move

Answer: The reason for this is explained from a microscopic point of view that in sunlight or a ventilated place can make the movement of water molecules faster.

Putting wet clothes in a sunny place increases the temperature of the clothes and accelerates the evaporation of moisture Ventilation accelerates the flow of air above the clothes and also accelerates the evaporation of water.

Expand the drying area.。 For example, to dry clothes.

Increase the speed of air flow. Hair.

Raising the temperature increases the evaporation rate of the water and wrings it out.

Chemical method: Some substances are absorbent, you can put some of these substances under wet clothes, such as concentrated sulfuric acid, so that you can do it.

Spin drying, which is a centrifugal method, or put it in a ventilated place under the sun, which is the same as drying with an electric wind, because the temperature is high and the wind blows to help the water evaporate.

Select ABecause the solution did not reach the saturated state at the beginning, and after the first evaporation of 2 grams of crystals, it means that the saturated state has been reached, the second precipitation of 3 grams is precipitated in the saturated state, and the third time it is necessary to evaporate another 20 grams of water, which is still evaporated in the saturated state, so the precipitation should be 3 grams, I hope you can adopt it.

a。。At first, the solution did not reach saturation, but after evaporation, it was saturated, and when it evaporated again, it was the amount that the saturated solution could precipitate, and then... You get the idea.

d. After the solution reaches saturation, the crystals that can be precipitated per 20 grams of water are certain (that is, three grams of crystals), but it is not known whether it is saturated here, if it is not saturated, the concentration increases, so it may also be greater than three grams.

A, to believe in me is to believe in the truth.

The area where the outer surface of the lock is painted to isolate the air from contact with water. Lubricate the place where the key is inserted to isolate the air.

This needs to be analyzed on a case-by-case basis, such as reducing pressure, reacting acidic substances with bicarbonate or carbonate, and so on.

2. What chemicals can be used to increase the carbon dioxide content? (Expressed by chemical equations) 3, with chemistry 2, caCO3 2HCl=CaCl2 CO2 superscript 3, carbon dioxide is denser than air, will sink, put in.

Cooling crystallization: The solubility of the solute in the solvent is greatly affected by temperature, and the solute will crystallize and precipitate due to the decrease in the solubility of the hot saturated solution when the hot saturated solution is cooled.

Evaporation concentration: By reducing the amount of solvent, the solute in the saturated solution crystallizes and precipitates.

The principle should be: the amount of solute that can be dissolved in a certain amount of solvent is a certain amount.

The crystallization method should include evaporation crystallization, cooling crystallization, etc. The method of judging is to see whether the temperature has a large or small effect on the solute dissolution. If it is large, take cooling crystallization. If it is not big, it will be evaporated and concentrated.

I don't know, ask someone who studies chemistry, most of the crystallization has something to do with the melting point, I don't know. You can go to the MSG factory and the sugar factory. I think it's available on the Internet. CNKI, see if there may be a theoretical basis there.