It s a difficult chemistry question, the hardest chemistry question I ve ever done, help solve it.

1.If the remaining gas is O2. The reaction is:

4no2+o2+2h2o==4hno3

The volume of NO2 is: (30-5)*4 5==20ml, and the volume of O2 is: 30-20==10ml

2.If the remaining gas is NO, then the reaction is:

4NO2+O2+2H2O==4HNO3---1)3NO2+H2O==2HNO3+NO---2) Through the reaction (2), it can be seen that NO2 15ml is required to generate 5MLno Through the reaction (1), the volume of O2 can be calculated as: (30-15)*1 5=3mL, so there are O2 3mL and NO2 27mL in the mixed gas

Solution: 3NO2+H2O=2HNO3+NO

2no+o2=2no2

Multiply both sides of chemical reaction equation 1 by 2 at the same time, and then add the reaction equation 24NO2 + O2 + 2H2O = 4Hno3

As oxygen is not easily soluble in water.

The gas remaining after the final reaction is definitely oxygen 5ml

The reaction consumes 30-5 = 25 ml of gas

The volume ratio of NO2 and O2 in the consumed gas is 4:1

Then the volume of NO2 is 25*4 5=20ml

O2 volume is 25 5 + 5 = 10 ml

NO2 can react with H2O to form HNO3 and NO

3no2+h2o=2hno3+no

No can react with O2 to form NO2

The total reaction equation is.

4no2+2h2o+o2=4hno3

The remaining 5ml of gas is 02 or NO

If O2 is excessive, then the O2 participating in the reaction is 5ml, and the NO2 is 20ml, if the NO2 is excessive, the NO2 participating in the reaction is 27ml, and the O2 is 3ml, so the original gas is NO2 20ML, O2 10ML or NO2 27ML, O2 3ML

Column chemical formulas are not fine.

4no2+o2+2h2o=4hno3

NO2:O2=4:1 reflects 25, plus the remainder does not reflect O2, so NO2 is 20 and O2 is 10

In addition, the landlord's last statement is some... It should be polite.

4n02+o2===2n205

The volume of NO2 is 24ml

The volume of O2 is 6ml

25:125 = solute: 1000

At 20 degrees Celsius, 1000g of copper sulfate saturated solution is 200gCuSO4, molecular weight is 160, molecular weight of CuSO4 pentahydrate is 250, if 1 gram of anhydrous copper sulfate can be precipitated XG crystals.

25：125=（200+1-x*160/250）：（1000+1-x）

Simplification, 25: 125=(201-x*16 25):(1001-x)5*(201-x*16 25)=1001-xx=

This question is actually not difficult, but there are some conditions hidden.

Taking a mixture of 16gfe2O3 and cuo is actually a distraction, useless stem.

First of all, the stem says that 100g of dilute sulfuric acid is added sufficiently, and then NaOH is added until no more precipitate is produced, which actually implies that dilute sulfuric acid is exactly completely reacted with 200g of 13% NaOH.

If you think that if there is still dilute sulfuric acid left, then add a little NaOH and there will be precipitation, and the stem says that after adding until there is no longer a precipitation, this implies that it happens to react.

So: H2SO4+2NaOH====Na2SO4+H2O98 80

x 200*13%

then x=(200*13%*98) 80=

Then the sulfuric acid solute mass fraction:

What else won't continue to hi me.

The NaOH mass of the reaction is 200 13%=26, and the sulfuric acid mass of the reaction is X

h2so4~2naoh

x 26x = mass fraction of 100 percent.

If you want to quantify this question.

Add 200g of 13% NaOH solution to the point that it does not produce precipitation" is understood as "adding 200g of 13% NaOH solution does not produce precipitation".

In this way, there is no solute but Na2SO4 in the solution after the precipitation is complete, and the precipitation is Fe(OH)3 and Cu(OH)2, and the mass of NaOH directly corresponds to the mass of H2SO4.

2naoh ~ h2so4

200*13% x

x=H2SO4 solute mass fraction: 1

High School Entrance Examination:

1.What is true in the following statements about the element germanium and its compounds is ( )a germanium has a higher first ionization energy than carbon and less electronegativity than carbon.

b Both germanium tetrachloride and carbon tetrachloride molecules are tetrahedral configurations.

c Germanium dioxide and carbon dioxide are both non-polar gas compounds.

d Both germanium and carbon are present in elemental substances with an atomic crystal structure.

Please name what substances can be used as electrolytes for galvanic batteries?