Solve two chemistry questions junior third Two junior high school chemistry questions

1 Bubbles are produced on the surface of the metal The solution changes from colorless to light green.

The blue copper sulphate solution appears red solid and the solution turns light green.

Colorless silver nitrate solution turns black and the solution turns blue.

2 Let the minimum form y3fe5ox then 16x (89*3+56*5+16x) = 26%.

x = 12

The chemical formula of this material is Y3Fe5O12

3 FeCl2·NH2O = FeCl2 + NH2OFECl2 + H2 = N2 High Temperature = Fe + 2The role of the shielding gas in the HCl reaction is to prevent Fe from reacting with the formed HCl as well as O2 in the air.

It's terrible when typing! ）

When a silvery-white sheet of iron is injected into dilute hydrochloric acid, the metal surface (bubbles are generated) and the solution changes from (none) to (light green) color.

When the iron sheet is put into the (blue) copper sulfate solution, the metal surface (red solid is generated) will be found, and after the complete reaction, the solution becomes (light green);

Immersing a red copper sheet in a (no) color silver nitrate solution will see the metal surface (with black solids formed) the solution turn (blue) color.

the production of bubbles; Not; Aqua.

Blue; Nigrescence; Aqua.

Not; Nigrescence; Blue;

There are bubbles without light green.

Blue produces a red solid and light green.

None of them turn black and blue.

Iron is dissolved in sulfuric acid to release hydrogen, 10g of iron powder is added to 50g of dilute sulfuric acid in the total mass of 60g, but the quality of the filtrate after filtration is , it means the mass of hydrogen and impurities generated, and the hydrogen is generated xg and impurities yg. The system of equations obtained by the chemical equation (x 2)*56+y=10

x+y=。To get the solution, then use the mass of hydrogen to find the iron mass, and then calculate the mass fraction.

Copper oxide is dissolved in dilute sulfuric acid to produce copper sulfate and water, and no gas is discharged. Copper and zinc alloy are dissolved in dilute sulfuric acid, copper does not react, and zinc reacts with dilute sulfuric acid to form zinc sulfate and hydrogen. That is, the hydrogen actually released in the right plate (the balance is balanced left and right, and the right and left side are 8) can calculate the mass of zinc (.

I've explained it in such detail, it's a bit too much to say if I don't give one!

1. +fe=>56%

The complete reaction of 50g of sulfuric acid is regarded as a limiting reagent of iron, and the mass ratio of iron to hydrogen is 56:2, so + g is equivalent to g of iron to generate g of hydrogen away, so iron is g, that is, 56%.

2.Dilute sulfuric acid does not react with copper, and copper oxide produces copper sulfate and water, and the quality remains unchanged. The gram on the right is less, which means that the gram of hydrogen is reduced, and the mass ratio of zinc to hydrogen is 65:2, so gram zinc participates in the reaction.

If this kind of thing is filled in the blanks, it will be pushed directly, and it will be pushed directly through the mass fraction and reaction coefficient (oral calculation), and if it is a short-answer question, then it will be an equation. Then it's just a verbal calculation, which is generally made up, and if it is not made up, then it is calculated in writing.

As far as the first question is concerned, according to the conservation of mass, we know that the mass before and after the reaction should be equal, but the mass of the filtrate obtained after the reaction is 10+50=60g before the reaction, so we know that the difference between them is the total mass of the hydrogen generated and the impurities filtered out. Therefore, we can assume that the mass of iron is x, the mass of impurities is y, and the mass of hydrogen produced is x|, according to the chemical reaction equation28, so we can get the system of equations x+y=10,x|28+y=, solve x is the mass of iron, and divide the mass of iron by 10 to get its mass fraction.

1、 ;

2. Let g the mass of hydrogen peroxide in the hydrogen peroxide solution be x 2H2O2 2H2O+O2

xx= 68*

x = mass fraction of solute in hydrogen peroxide solution = 100% = 5% A: The mass fraction of solute in this hydrogen peroxide solution is 5%.

The first question lacks volume, and the second question: 2H2O2 2H2O+O2 mass of oxygen =

Mass of hydrogen peroxide = grams (calculated according to the equation).

Mass Score =