Chemistry Problem! Hurry, hurry!

a+hcl =acl2 + h2

a Therefore, the solution is: a=56, which is fe. Iron.

The most ** of b is +6, so its hydride is h2 b,, and the solution is b=32, which is s. Sulfur.

a+2hcl=acl2+h2

a gram a = 56 grams.

The negative valency of b = 6-8 = -2, the hydride is H2B, B (2+B) = , B = 32

A is iron and B is sulfur.

The chemical formula of the most ** oxide of b is bo3, so b is the sixth main group element. According to the hydride mass fraction, B is an S elemental substance with a relative atomic mass of 32.

Write out the reaction equation between A and HCl, and according to the equation, we can see that A is Fe elemental with a relative atomic mass of 56.

You have a limited number of words and can't write the process.

a+2hcl=acl2+h2

xx = a is iron with a relative atomic mass of 56

b is sulfur, h2s 32 34*100%=, relative atomic mass 32

a+2hcl=acl2+h2x 2

x yields x=56a, atomic mass: 56

Element B, its most ** oxide chemical formula is Bo3, then B hydride is H2BB (B+1*2)=

b=32b, atomic mass: 32

a+2hcl=acl2+h2

x yields x=a atomic mass.

B hydride is BH2

b/(b+2)=

Get b = 32

Let the mass of sodium carbonate in the long-standing sodium hydroxide be X, and the mass of sodium hydroxide generated by the reaction is YN2CO3 + Ca(OH)2 CaCO3 +2NaOH106 100 80

x 2 g y

The solute of the solution obtained by x= g y= g is NaOH

Solut mass fraction.

The mass of the original NaOH + the mass of the generated NaOH ) (the mass of the solution) = ( (12+65+25-2) =

The solute mass fraction of the resulting solution after the reaction is.

According to the "exactly complete reaction", it should be understood that the precipitation is only calcium carbonate, then the mass of the final solution is 12 + 65 + 25-2 = 100 grams.

From the chemical equation Na2CO3 + Ca(OH)2=CaCO3 + 2NaOH, it can be calculated from the generation of 2 grams of calcium carbonate that the reaction of grams of sodium carbonate is generated, and the generation of grams of sodium hydroxide is generated, then the mass of sodium hydroxide in the final solution is grams, and the solute mass fraction of the sodium hydroxide solution obtained after the reaction is.

na2co3 + ca(oh)2 === caco3 ↓ 2naoh

x 2 yx= y=

Then the solute mass fraction in the solution = (

There is a 2g precipitate indicating that some CaCO3 is generated, and it can be known that some NaOH reacts with CO2 to remove the previous Na2CO3,12+

2 ml (one flat finger); Cover the bottom of the tube.

2. a jar; medicine spoons; Paper.

1) Flat; Tweezers; Test tube mouth.

2) Lay flat; medicine spoons; Bottom.

3. Fine-mouthed bottles.

2) head-up; Burette; The lowest.

3) Dropper; Above; oblique placement; Reverse; Back.

4、；Paper. Left tray; Glass; Left; Right.

5. A (the amount to be weighed cannot be changed, and the left side indicates that there are more drugs) 6, D7, C (because the pallet balance can only be accurate.)

8. B (looking down means that the value seen is larger than the actual value, so the actual remaining amount is small) 9, C (the operation is incorrect, and the chemical experiment operation must be careful and meticulous) 10, (1) 10

2) Cleaning. 3) Insert the plug.

2 ml, cover the bottom of the tube with an Erlenmeyer flask medicine spoon.

1、a2、b

3、c4、d

5, B6, it is known that if there is residual air in the bulb will greatly shorten the life of the bulb, in order to prolong the service life of the incandescent lamp, the bulb often has a small amount of red phosphorus, its function is to react with the oxygen in the bulb, the text expression of the reaction is 4 red phosphorus + 5 oxygen = 2 phosphorus pentoxide.

7. The two experiments of A and B have something in common: the bottom of the gas collection cylinder is pre-filled with a small amount of water, and their functions are respectively.

Armor:; Second:. No picture, no way)

8. The instrument for clamping the fine iron wire is called a crucible clamp, and the reaction belongs to the oxidation reaction from the type of reactants and products.

1 A, with water and CO2

2 b, continue to burn, burn more vigorously, extinguish.

3C product P2O5 is solid.

4 d5 a

6. Reaction with residual air, P+O2-P2O57

1：a ( h2o)

2:b (no obvious resurgence of wood strips**) 3:c (phosphoric acid droplets).

4:d (CO2+CAO==CAC3 3O2==2O3 is just a mixture).

5:b (oxygen only has flammability, s+o2==so2, 2so2+2==2so3, first SO2, carbon dioxide is colorless and odorless).

6: Remove possible O2 red phosphorus + oxygen from the bulb Phosphorus pentoxide 7:8: Tweezers oxidize.

The main raw material of the candle is paraffin wax [chemical properties] paraffin wax+ (igniting the cotton wick), generating carbon dioxide and water 2C8H18 +25O2 = 16CO2 +18H2O )