One chemistry question for the second year of junior high school, and one chemistry question for the

The anode produces oxygen and the cathode produces hydrogen).

2h2o = 2h2 + o2

36 2mol

xgx=I hope you find my question helpful!!

In the experiment of electrolysis of water, the negative electrode releases hydrogen, the positive electrode releases oxygen, and the ratio of the release is two to one, and the negative electrode is released, and the positive electrode should be released.

then decompose 9g

2h2o=2h2+o2

First of all, it can be clarified that the volume ratio of gas produced by the positive and negative electrodes is 1:2If it is collected on the negative electrode, oxygen should be collected on the positive electrode.

Knowing that oxygen is collected, the mass of oxygen is converted in units) 2H2O=2H2+O2

x, so x=36*

Answer: Let the valency be x, j metal is r, then rclx, r(oh)xThen from the smile of the tent: r+, r+17x=n, from the early and quiet subtraction of the two formulas, x=m-n

According to the chemical valence and relative atomic mass of magnesium and aluminum, it can be known that the ratio of dilute sulfuric acid consumed by magnesium and aluminum (you can set it to 27g) is 3 4

Let both masses be m

The mass of oxygen in magnesium oxide is 16/40m

The mass of oxygen in calcium oxide is 16/56m

Therefore, the mass ratio of the oxygen element contained in magnesium oxide to calcium oxide is 16m/40 and 16m/56 = 7

So the ratio of the oxygen atoms contained in magnesium oxide to calcium oxide is also.

1 (subscript) x7

1 (subscript) x5 = 7:5

The quality score is:

Oxygen = 3 * 16 = 48

Relative molecular weight.

48/r(160-48)/2=56

32g*2.The mass fraction of x in a is 50%.

The chemical formula of a is XY2

Then x=2y lets b have a in y.

then x has 2a.

2ax：ay=4：6

The solution is x:y=1:3 and c

3.A serving of CO2 has two O's

A co-or

So the ratio of CO2 to the number of CO.

is 1:2, then the mass ratio is.

If the masses of CO2 and CO are equal, let a CO2, and B CO have ACO2=BCO

i.e. 44a = 28b

The solution is a:b=7:11

So the ratio of carbon to atom is 7:11

The first question r is Fe iron. The relative atomic mass is 56

32g contains 32*

r2:o3=7:3

r times 2 times 3 = 16 times 3 times 7

r=5632 times 70% divided by 2=g.

According to the title: x=2y

ax:by=4:6

Synopid: a:b=1:3

The chemical formula is XY3

CO2 volume: When the CO volume is 1:2, the mass of oxygen is the same, and the mass ratio is 76:120

32a+44a=44b+16b

Solution: a:b

Question 1. R is Fe iron element. The relative atomic mass is 56

32g contains 32*

r2:o3=7:3

r times 2 times 3 = 16 times 3 times 7

r=5632 times 70% divided by 2=g.

According to the title: x=2y

ax:by=4:6

Synopid: a:b=1:3

The chemical formula is XY3

CO2 volume: When the CO volume is 1:2, the mass of oxygen is the same, and the mass ratio is 76:120

32a+44a=44b+16b

Solution: a:b

o The quality fraction is:

Oxygen = 3 * 16 = 48

Relative molecular weight.

R32G* has a mass fraction of X in a 50%.

The chemical formula of a is XY2

then x=2y is set to b.

Y has a. then x has 2a.

2ax：ay=4：6

The solution is x:y=1:3 selection. c

A serving of CO2 has two O's

A co-or

So the ratio of CO2 to the number of CO.

is 1:2, then the mass ratio is.

If the masses of CO2 and CO are equal, let a CO2, and B CO have ACO2=BCO

i.e. 44a = 28b

The solution is a:b=7:11

So the ratio of carbon to atom is 7:11

1. 2na2o2+2co2*****==2na2co3+o22.Solution:

Let the daily sodium peroxide mass in the submarine be x2Na2O2+2CO2*****==2Na2CO3+O2110 32

x 24*50l*4/

110/x=32/3200g

x = 3200g * 110 32 = 11000g = 11kg A: 11 kg of sodium peroxide is needed in this submarine every day.

1.Choose B because the water will flow backwards into the test tube, and the hot test tube will burst when it encounters water.

Analysis: Potassium permanganate is first thermally decomposed into manganese dioxide, potassium manganate, and oxygen manganese dioxide will catalyze the thermal decomposition of potassium chlorate into potassium chloride and oxygen, and the text expression is: potassium chlorate + potassium permanganate potassium manganate + potassium chloride + + manganese dioxide + oxygen.

Have fun!

You're too little to score, so I'll help you out.

To make the wastewater neutral, it is necessary to make the HCl in the wastewater react with sodium hydroxide.

There is Cl2 in 1000m3 1000* through Na2SO3+ Cl2+H2O== Na2SO4+2HCl

1000* x

x=1000*

So there is a total HCL of 2000*

Then according to HCl + NaOH = = = NaCl + H2O2000 * Y

Find y=2000*40g and convert the rest of the units yourself.

Chlorine gas corresponds, hydrochloric acid corresponds to 1mol, 1000 cubic meters of sewage has 500mol chlorine, 1000mol hydrochloric acid, according to the reaction equation one mole of chlorine gas to generate two moles of hydrochloric acid, so the first step of the reaction to generate 1000mol hydrochloric acid, so the total hydrochloric acid has 2000mol, according to the second equation, one mole of hydrochloric acid consumes one mole of sodium hydroxide, so 2000mol of sodium hydroxide is needed, and the relative atomic mass of sodium hydroxide is 40, so 80000g is needed

Count the nitrogen content of ammonium nitrate first.

The mixture is only 20%.

So the nitrogen mass fraction of another substance must be less than 20%.

i.e. c is the correct answer.