How to write the last blank chemistry fill in the blank question in the first year of high school?

A CH4 is made up of 5 atoms, so divide by 5

naoh

2Al+2NaOH+2H2O==2Naalo2+H2 (Since magnesium cannot react with NaOH, magnesium is the insoluble substance) HClMgCl2

mg+2h+ ==mg2+ +h2↑

h2so4alo2- +h+ +h2o==al(oh)3↓h2so4

al2(so4)3

al(oh)3+3h+==al3+- 3h2o

Sodium hydroxide solution, 2AL + 2NaOH + 2H2O ==== 2Naalo2 + 3H2, dilute hydrochloric acid, MgCl2, mg + 2H+ ==== Mg2+ +H2, dilute hydrochloric acid, ALO2- +H+ +H2O ==== Al(OH)3, dilute sulfuric acid, Al2(SO4)3, Al(OH)3 + 3H+ ==== Al3+ +3H2O

If the fertilizer of magnesium aluminum alloy is used dilute sulfuric acid, dilute hydrochloric acid sodium hydroxide solution to prepare MgCl2 Al2(SO4)3 solution, firstly, the waste can be added to sodium hydroxide, and the chemical equation for the reaction is filtered, and the incompromising matter is added to the dilute sulfuric acid to obtain Al2(SO4)3 solution, and the ion equation of the reaction is Then, if you want to add an appropriate amount of dilute hydrochloric acid to the filtrate, the ion equation of the reaction is to filter and add the precipitate to the solution The ion equation of the reaction is

Naalo2 (Reason: 2Al+2NaOH+2H2O=2Naalo2+3H2 (gas arrow)).

Zn+2NaOH = Na2Zno2+H2 (gas arrow) mimics the reaction of aluminum with sodium hydroxide, but note that the valence state of zinc determines that there are two sodium atoms in the salt. In addition, there is no water in the reactants, because it is just balanced.

1, 3, and 4 can be identified from each other. Because, aluminum sulfate and zinc sulfate add sodium hydroxide drop by drop, there will be no precipitation due to excessive sodium hydroxide, and precipitation will occur later; If sodium hydroxide drops into aluminum sulfate and zinc sulfate, due to a small amount of sodium hydroxide, there will be precipitation at once, and then disappear with the excess of sodium hydroxide. But ammonia, weak alkali.

No matter how much ammonia is excessive, aluminum hydroxide will not dissolve, and the mutual dripping phenomenon is white precipitate and will not dissolve. Therefore, it cannot be judged. However, zinc hydroxide can be soluble in ammonia due to the combination of ions.

Then the ammonia droplets zinc sulfate, first white precipitate and then dissolve; In reverse, there is no phenomenon at first, and then white precipitates.

Al3+ + Al(OH)3 (precipitation arrow).

1, Naalo2 (equation: 2AL+2NAOH+2H2O==2NAALO2+3H2).

2,Zn+2NaOH==Na2Zno2+H23, The key is that aluminum hydroxide is insoluble in ammonia, so the phenomenon of dropping with each other is the same, all of which produce precipitation, so they cannot be identified, while the other three groups are not affected by the phenomenon when the metal salt droplets are added to the alkaline water, and then the precipitation is generated, and the phenomenon of the alkaline water dropping into the salt solution is to form a precipitate and then the precipitation is gradually dissolved, so it can be distinguished).

4,al3+ +3nh3h2o == al(oh)3 + 3nh4+

Baking soda reacts with HCl: NaHCO3 + HCl == NaCl + H2O + CO2

The reason why NaOH solution cannot be used is that NaOH also reacts with carbon dioxide.

The reason why NaCO3 cannot be used is that if NaCO3 is excessive, NaHCO3 is generated and the reaction does not continue, and the NaCl + H2O + CO2==NaHCO3 + HCl reaction occurs, consuming carbon dioxide.

HCl, HCO3-+H+=H2O+CO2 in carbon dioxide is usually removed with a saturated solution of baking soda

The reason why NaOH solution cannot be used is:

oh-+co2=co3 2-

The reason why na2CO3 cannot be used either:

co3 2- +co2+h2o =2hco3 2-

The process of chemical reaction is actually just that.

Fracture of old chemical bonds).

and (formation of new chemical bonds).

2. There is a kind of atom that can form a diatomic molecule H2D2T2, and the ratio of their elemental density is (1:2:3) under the standard condition, and the ratio of their proton number in 1mol of each of the three elemental elements is (1:

1:1) ratio of neutrons (0:2:

4), the ratio of the number of protons in each of the three elemental substances (6:3:2) and the ratio of the number of neutrons (0:

3:4) The ratio of the number of electrons contained in 1L of various elemental gases at the same temperature and pressure is (1:1:1).

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