A junior high school chemistry problem, seeking the process!

cuo＋co＝cu＋co2

The weight of the solid reactants is the oxygen in all copper oxide, and the mass of the original copper oxide is m: 16 64+16 m

m = then copper is grams.

Poor quality is used.

Cuo Co Cu CO2 Solid quality is poor. mm=

The mass of the copper in the original mixture.

What is left after co restores cuo is cu, so the quality of cu is the quality of o, so the quality of cuo is =

So the quality of the cu is.

Note This kind of problem should use the simplest method, it is too troublesome to waste time and useless, the method on the 4th floor is the easiest, and the others are very troublesome. From the perspective of later learning, the difference method is also very important.

Using the mass fraction method to find it, in short, it is because the copper oxide and carbon monoxide react, so that the oxygen loss in it causes the mass to decrease. According to the mass fraction of oxygen in copper oxide, the mass of copper oxide is calculated, and the rest is the mass of copper.

First of all, the atomic mass number: N-14, H-1, C-12, O-16, , S-32 ammonium sulfate has a nitrogen mass fraction of (NH4)2SO4:14*2 (14*2+4*2+32+16*4)=

Now the nitrogen content is 20%, indicating that the nitrogen content in the impurities is less than 20%.

Then calculate: a:14*2 (14+4*1+14+16*3)=b:14 (14+1*4+1+12+16*3)=c:14*2 (12+16+14*2+1*4)=d:14 (14+4+

It was found that the compound in option B had less than 20% nitrogen content, so B was chosen.

I don't know if the pro is **miscalculated. Did you forget that the subscript 2 outside the parenthesis (nh2)2 is to be multiplied?

If you still don't know how to ask additional questions, I'll answer it again when I see it.

Incidentally, CO(NH2)2 is the compound with the highest nitrogen mass fraction. Remembering words is helpful for multiple choice questions! Its name is urea, and it's urea in English.

Ammonium sulfate contains n is.

Now the N content has become 20%, indicating that the impurity contains less than 20% N

35% chose B

To tell you the method, first you find the mass fraction of nitrogen in ammonium sulfate, and then find the mass fraction of nitrogen in different substances in the four options, 20% must be between the mass fraction of nitrogen in ammonium sulfate and the mass fraction of nitrogen in the substances in the correct option.

The relative molecular mass of a is 80 to calculate the nitrogen content is;

The relative molecular mass of b is 79 and the nitrogen content is calculated as;

The relative molecular mass of c is 60 to calculate the nitrogen content is;

The relative molecular mass of d is 54 to the nitrogen content is. 026；

Only b is the closest to each other, so the answer is b;

The domestic garbage treated by landfill can not effectively improve our living environment, but causes environmental pollution, so the general domestic garbage must be treated centrally;

Natural gas is a mixture of hydrocarbons, and the products of combustion are only carbon dioxide and water, and carbon dioxide is not an air pollutant;

Gasoline has a complex composition and emits carbon monoxide, nitrogen, sulfur and other compounds as fuel.

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Option B; Because the domestic garbage disposed of by landfill method cannot effectively improve our living environment and cause environmental pollution; In addition: the products of natural gas combustion are carbon dioxide and water, carbon dioxide is not an air pollutant, but gasoline as a vehicle fuel will emit carbon monoxide, nitrogen, and sulfur compounds, which are all air pollutants!

Carbon dioxide is not an air pollutant.

Since none of them can be degraded, neither can they be landfilled.

a, the air itself contains CO2, and burning natural gas produces CO2 and H2O, which has a greenhouse effect at most, but does not pollute the air.

b. Degradable characteristics are that after reaching a certain service life and being discarded, under specific environmental conditions, due to obvious changes in its chemical structure, it will cause some performance loss and appearance changes and degrade, which is harmless or less harmful to the natural environment.

Non-degradable garbage cannot disappear even if it is buried in the soil, such as waste batteries, which will also pollute the environment.

b。The use of landfill method to dispose of non-degradable household waste Landfill cannot reduce the pollution of garbage to the environment.

Thinking about it from another angle, he said to improve, so there is a comparison, you think that compared with natural gasoline, there will be a lot of black smoke produced by immortal gasoline, and this will improve the environment! The second is that it can't be degraded, or it still needs to be landfilled, doesn't this lead to more non-degradable waste? Doesn't this aggravate the environment?

If we say that we use degradable instead of non-degradable, this is improvement.

The landfill method cannot dispose of non-degradable garbage, which destroys the soil, CO2 does not pollute the air, gasoline combustion produces nitrogen oxides that pollute the air...

Carbon dioxide is present in the air and does not pollute the environment, only contributing to the greenhouse effect (and as a result of excessive emissions). Just think of carbon dioxide that humans and even animals exhale when they breathe.

Gasoline will burn incompletely, producing... Think about the bottom of your pot) As for b, it is not sustainable.

And contaminate the soil.

Because carbon dioxide is not a pollutant in textbooks, it has no impact on the environment and will only cause the greenhouse effect, so choose B

Carbon dioxide is just a greenhouse effect, and there is already carbon dioxide in the air, so it will not pollute the air.