Some junior high school chemistry questions! Tell me!

1.What's the problem?

2.The aqueous solution of carbon dioxide is acidic.

3.Carbonic acid decomposes easily and carbon dioxide escapes.

4.Copper oxide and carbon powder.

5.Produces toxic carbon monoxide.

6.Sulfur elemental substances produce sulfur dioxide.

7.Oxide of phosphorus.

8.Hydrogen. 9.Methane.

10.Ethanol.

11.Carbon monoxide.

12.Calcium carbonate.

13.Add hydrochloric acid.

,c02+c=2co,3co+fe2o3=2fe+3co23. h2co3=co2+h2o

heating = Cu + CO2, CO2 + Ca(OH)2 = CaCO3 + H2O insufficient amount).

8.Hydrogen 2H2+O2=2H2O

Ignition = 3H2O + 2CO2

Reagent 1 was added to the barium chloride solution to generate a white precipitate.

The addition of reagents may be carbonates, silver salts, sulfates.

The corresponding precipitates are barium carbonate, silver chloride, and barium sulfate.

Add reagent 2 to the filter residue, produce bubbles, white precipitate does not disappear, produce bubbles indicate that it contains carbonate, indicate that reagent 2 contains hydrogen ions, it can be regarded as hydrochloric acid sulfuric acid and nitric acid, only after adding sulfuric acid to continue to generate barium sulfate will not disappear, so.

Reagent 1 is carbonate and reagent 2 is sulfuric acid.

Reagent 1 is carbonate (e.g., sodium carbonate) and reagent 2 is sulfuric acid.

Plus 1 has a white precipitate, so let's see, there is Ba2+ Cl-, a total of 3 precipitates BaCO3 Baso4 AGCL

Then the reagent is added to the filter residue and there are bubbles, so the acid is added to produce CO2, so the precipitate is BaCO3

Then there are both bubbles and precipitation, so only H2SO4 is added to form BaSO4 that is insoluble in acid and water

Therefore, 1 is a carbonic acid or carbonate solution (generally there is not much carbonic acid as a reagent, so the carbonate solution is better).

2 is sulfuric acid.

If two liquids are miscible with each other, they are solvents and solutes to each other, that is, it is okay to designate either as a solvent, and the other is a solute. It is customary to use a large amount as a solvent and a small amount as a solute.

However, if one of the liquids is water, it is customary to specify it as a solvent regardless of the amount of water.

52 degree liquor is a volume concentration.

As long as there is water, no matter how much or how little it is, water is a solvent...

Generally, if there is water in the solution, water is considered as a solvent.

General provisions, conventions. End.

When there is water, it must be a solvent.

That's what my friends say.

Answer the question. Sodium hydroxide.

Hydroxide is judged to carry calcium all.

Alkali. Reacts with acids.

Say who comes first. Combine specific.

acids and their products. Are you sure. Appearance.

Whoever comes first. Example: sodium hydroxide.

Calcium hydroxide rock preparation solution.

Carbonic acid (i.e., CO2 gas is introduced) is added

Since first of all. Now white.

Calcium carbonate precipitation. Place. Appearance.

It first reacts with calcium hydroxide;Sodium carbonate.

Sodium bicarbonate. Carbonic acid.

Two kinds of salt. The former is called. Salt. said.

Acid salts. Reacts with acids and bases. Angle. See.

Sodium carbonate. It can react with acids.

Sodium bicarbonate is both.

with acids. Reacts with alkali.

Both salts react with acids.

then sodium carbonate precedes sodium bicarbonate: CO32-+H+=HCO3- (limited to web mode.

Yes. Written. Style. Just.

hco3-+h+=co2+h2o；Hydrochloric acid.

Sulfuric acid both. Strong.

It depends on. Alkaline reactions and products. Exist. State.

Are you sure. Appearance. In. Whoever comes first.

Example: hydrochloric acid. Sulphuric acid. Mix.

Solution. Add sodium hydroxide.

then both. Whoever precedes whom.

Carry out the reaction. If you join.

Strong alkali barium hydroxide.

Because. To add barium hydroxide.

Instantly. Sulfuric acid with.

White. Barium sulfate precipitation. Old. Appearance.

In. Sulfuric acid reacts first and is coarsely washed out.

Some. Lab do experiments plus.

Verify. Question 2:

Say. Calcium hydroxide.

Slightly soluble in water. Water. Contain. Measure.

Calcium hydroxide. Sure.

Now calcium hydroxide precipitates.

Judgment. Experimental phenomenon.

Theory. Judgment is a matter of waiting.

High. Solubility product. Number. Self.

Clear. Problem 3: Saline solution.

Acidity and alkalinity. Judgment.

Beginning. To master the requirements of the class. Small table. See.

Yes. Soda is alkaline.

Grass ash (i.e. potassium carbonate) is alkaline, etc. Cope. Test.

Teach. Simple. Judgment. 1、fecl2

Consists of a strong acid (hydrochloric acid) with a weak base (ferrous hydroxide).

Salt. It is called strong acid and weak alkali salt.

salts are acidic; Similar.

Ammonium sulfate (composed of strong acid sulfuric acid with weak base.

Ammonia hydrate. Salt.

The rest is analogized) aluminum nitrate (composed of strong acid nitric acid and weak alkali aluminum hydroxide.

salt) and so on. 2. Na2CO3 is called strong alkali weak acid salt (by the reaction of strong alkali sodium hydroxide with weak acid carbonic acid.

Salt. and so on).

salts are alkaline; 3. Strong acid and alkali salt.

Sodium chloride (by the reaction of strong acid hydrochloric acid with strong alkali sodium hydroxide.

The rest is analogous), potassium nitrate, etc.

Sex. Answer: Hopefully. Help. Wish.

Pass. Performance.

1x3y= 14*1+19*3=71

1 +3 requires 3 -1 to neutralize it.

Since there are only two elements, the overall valency of the compound or element is zero, it can be said that the form of the compound is xy3 and the relative molecular mass of the compound is 14 + 19 * 3 = 71