10 chemistry questions in the first year of high school, I can t do it, everyone helps

1. The white precipitate is barium sulfate and barium carbonate, and the excess dilute nitric acid is added to the treatment, and only barium sulfate is left in the precipitation.

na2so4+ba(oh)2=baso4+2naohx

x*142/142= x=

2. The quality of barium carbonate is.

baco3+2hno3=co2+ba(no3)2y

y/44= y=

The volume of the gas produced under standard conditions is:

3. Add 100ml of barium hydroxide solution to generate a precipitate, barium carbonate Na2SO4, Na2CO3.

From Na2SO4+Ba(OH)2=BaSO4+2NaOHna2CO3+BA(OH)2=BaCO3+2NaOH to obtain the amount of solute in the final filtrate is .

(1) The precipitate formed by the reaction with barium hydroxide has barium sulfate and barium carbonate, and the insoluble in nitric acid is barium sulfate, n(baso4)=n(na2so4)=

2) Barium carbonate is soluble in nitric acid, and the gas produced is carbon dioxide, n(CO2)=n(baCO3)=(

v（co2）=

3) From the reaction equation, it can be seen that the solute in the filtrate is sodium hydroxide, and then from the law of conservation of elements, it can be seen that n(Naoh)=2N(Na2SO4)+2N(Na2CO3)=

A mol nitrogen atom in a mol no A mol oxygen atom and B mol O2 has 2b mol oxygen atom in it. So the total number of oxygen atoms is a+2b mol.

Then the ratio of the number of oxygen atoms of the nitrogen atom = a:a+2b

a:(a+2b).It has nothing to do with the volume v, and the total number of atoms does not change at all, regardless of how the chemical reaction proceeds

a mol o: a mol b mol o2 o: 2b mol; So n:

o=a；（a+2b）

a:（a+2b）

Because A mol no has a mol n atom and a mol o atom, while b mol o2 has 2b mol atoms, so...

To determine the sodium carbonate content in soda ash, the reaction Na2CO3 + H2SO4 = Na2SO4 + CO2 + H2O is used, and the amount of CO2 generated by it is only necessary to measure.

The function of a is to absorb CO2 and H2O from the air to avoid unnecessary errors in the measurement results.

The role of B: The above chemical reaction occurs.

The role of C: Absorption reaction to produce H2O.

D Function: Absorption of CO2 gas.

The role of E: Same as A.

1): All the gases produced by the reaction are blown into C to make it completely absorbed to ensure the accuracy of the experiment.

3): Concentrated sulfuric acid solution.

5): The mass of CO2 gas produced by the reaction is: (m2-m1), and the amount of the substance is:

M2-M1) 44, the mass of Na2CO3 participating in the reaction is: [(M2-M1) 44]X106, and the mass fraction of Na2CO3 is: X100%.

Add a mol of sodium sulfate to the solution, just so that the barium ions are completely precipitated, Ba2+ +SO42- = BaSO4 4, so the barium ions have amol

Take another part and add a solution containing B mol of silver nitrate, which happens to completely precipitate Cl- +Ag+ = AgCl with chloride ions

So chloride ions have bmol

Because of the mixture of BaCl2 and KCl.

So the k ion has b-2amol

Because 500ml is divided into 5 aliquots, i.e. 100ml, the concentration of potassium ions in the mixed solution is 10b-20amol l

Take a portion and add a mol of sodium sulfate to the solution, just so that the barium ions are completely precipitated in each aliquot, there is Ba2+amol. Then BaCl2 is amol, and another part is added to a solution containing B mol of silver nitrate, which happens to completely precipitate chloride ions in each equal part, and there is Cl Bmol.

Cl in KCl is (B2A)mol

k is (b 2a)mol

The k in the original mixture is 5(b 2a)mol

The K concentration in the original mixture is 5(b 2a)mol

According to the conservation of charge: n(ba2+)=n(so42-)=5a mol is obtained from sodium sulfate (note that it is divided into five equal parts, *5), n(cl-)=n(ag+)=5b mol, so n(k+)=5b-2*5a mol c(k+)=(5b-10a) mol l

Divide 500 ml of solution into 5 aliquots of 100 ml each. N(Ba2+)=A mol, N(Cl-)=B mol in each portion, and N(K+)=(B-2A)mol according to the charge conservation relationship. then c(k+) = (b-2a)mol = 10(b-2a) mol per liter.

Idea 1:

In a gas mixture of hydrogen and carbon monoxide:

The mass of hydrogen is, that is; The mass of carbon monoxide is , that is.

h2+guo=gu+h2o

co+guo=co2+gu

2h2o+2na2o2=4naoh+o2

2co2+2na2o2=2na2co3+o2

So in the end, all the sodium peroxide becomes NaOH and Na2CO3, and according to the conservation of H atom and C atom, there is finally NaOH and Na2CO3;

The original number of moles of sodium peroxide for the formation of NaOH and Na2CO3 is based on the conservation of Na atoms), so the increased mass of the final solid is:

Idea 2: The chemical equation in the question:

2h2+2guo=2gu+2h2o

2h2o+2na2o2=4naoh+o2

2co+2guo=2co2+2gu

2co2+2na2o2=2na2co3+o2

From the equation, it can be seen that two hydrogen gases produce two waters, and the two waters react with sodium peroxide, and the increased mass of the solid is just the mass of two water minus the mass of one oxygen, that is, the four sodium hydroxide produced by two sodium peroxide just absorb the mass of two hydrogen.

In the same way, carbon monoxide reduces copper oxide, absorbs 2 oxygen atoms, and produces carbon dioxide. Finally, the reaction with sodium peroxide releases another oxygen, which means that the added mass of the solid is just the mass of carbon monoxide.

That is, the mass of the solid increases just the mass of a mixture of hydrogen and carbon monoxide.

We should be good at using the principle of conservation of atoms in chemical reactions to think.