Some chemical reaction phenomena the third year of the first month .

The phenomenon of aluminum wire being put into copper sulfate solution ———

According to the displacement reaction.

Al+CuSO4 == Al2(SO4)3 + Cu shows that when the aluminum wire is put into the copper sulfate solution, the blue color of the solution becomes lighter, and a layer of red solid is attached to the aluminum wire.

The phenomenon of copper wire being put into silver nitrate solution ———

According to the displacement reaction.

Cu + 2agno3 == Cu(NO3)2 + 2ag shows that when the copper wire is put into the silver nitrate solution, the copper wire is attached to a white solid, and the solution changes from colorless to blue.

The phenomenon of carbon monoxide reducing iron oxide ———

The color of the solid changes from red to black, forming a gas that can make the clarified lime water turbid.

The phenomenon of copper hydroxide decomposing under heating conditions ———

The blue copper hydroxide turns into a black solid, and water droplets form on the walls of the test tube.

1.There is a red substance precipitated on the surface of the aluminum wire, and the solution gradually faded from light blue to colorless.

2.There is a silver substance precipitated on the surface of the copper wire (it is black in the solution, and it is silver when it is taken out), and the solution gradually turns light blue.

3.The red solid powder turns black, producing a colorless and odorless gas, which can make the clarified lime water turbid.

4.The blue precipitate gradually turns into a black solid, producing a gas that turns anhydrous copper sulphate blue.

Precipitates a red substance (elemental copper).

Precipitates a white substance (elemental silver).

Produces a silvery-white solid (elemental iron).

Produces a black solid (copper oxide).

1. The blue color of the solution recedes, and a red substance precipitates.

2. The solution becomes lazy, and a silvery-white substance precipitates.

3. The clarified lime water becomes turbid, and the solid changes from red to black.

4. Generate a black solid precipitate (Cu(OH)2 solution) to form a colorless liquid, and the solid becomes black.

1. A red substance is attached to the solid surface, and the solution gradually changes from blue to colorless.

2. The silvery-white substance is gradually attached to the copper wire, and the solution changes from colorless to blue.

3. Produce a gas that makes calcium hydroxide turbid, and the solid changes from red to white.

4. Water droplets appear in the test tube, resulting in black solids.

(1) Acid + salt — new acid + new salt.

The acid in the reactant must be soluble, and at least one of the substances in the product is gas or precipitate or water.

For example: 2HCl CaCO3=CaCl2 H2O CO2

2) Acid + Alkali – Salt + Water.

At least one of the reactants is soluble.

For example: H2SO4 Cu(OH)2=CuSO4 2H20

3) Salt + Salt — Two new salts.

Both salts in the reactants are soluble at the junior stage, and at least one of the two salts obtained from the reaction is insoluble.

For example: Na2SO4 BACl2=2NaCl BaSO4

Attached: Two salts (one is an insoluble or insoluble unstable salt, and the other is soluble) metabolizes to form a more stable (or stable) salt (there are insoluble salts in both reactants and products).

Salt (insoluble or insoluble) + salt = two new salts.

bas+na2so4=baso4+na2s

baco3+na2so4=baso4↓+na2co3

4) Salt + alkali — new salt + new alkali.

The reactants are generally soluble, and at least one of the products is a precipitate or gas (only ammonia salts react with alkali to form gas).

For example: 2NaOH CuSO4=Na2SO4 Cu(OH)2 ; naoh＋nh4cl=nacl＋nh3↑＋h2o

Fe(OH)3 does not react with NaCl.

According to the definition of junior high school, if it is all aqueous.

1 No, 2 most of the OK, but for example, silicic acid and aluminum hydroxide solids can not react, 3 Most of them are not, but as mentioned earlier, sodium hydroxide and aluminum hydroxide can react in the aqueous phase 4, if the precipitated compound can be formed in water, then it can react.

5 Yes. 6 If both alkali and salt are soluble and will produce precipitates or gases, then it can be reflected that things can't be remembered too dead, because the concept of junior high school is still relatively rudimentary. There are exceptions to everything.

1. The acid-acid reaction --- is not feasible.

2. Acid-base reaction - at room temperature.

3. Alkali-alkali reaction - at room temperature (AI(OH)3+NaOH) 4. Salt-salt reaction - at room temperature.

5. Acid reaction --- at room temperature.

6. Alkali salt reaction - at room temperature.

Acids cannot react with acids, others can react at room temperature.

It can be done under specific conditions depending on the reactants.

There are many precipitates in the chemical reactions learned in junior high school, especially the part of acid and alkali salts, which can produce magnesium hydroxide, barium sulfate, silver chloride, barium carbonate, calcium carbonate, copper hydroxide, iron hydroxide, etc., which are precipitated, of which the first five are white, copper hydroxide is blue, iron hydroxide is reddish-brown, and the most important reaction of heating is calcium oxide and water reaction, in addition, concentrated sulfuric acid dilution and sodium hydroxide deliquescent are also exothermic.

The more important ones left are 1The reaction between iron and copper sulfate is as follows: there is a red substance on the surface of silvery-white iron, and the solution changes from blue to light green;

2.Reaction between aluminum and copper sulfate: a red substance is formed on the surface of silvery-white aluminum, and the solution changes from blue to colorless (or the color of the solution becomes lighter).

3.All reactions in which gas is formed are bubbles;

4.Iron burns violently in pure oxygen to produce black matter.

Be careful not to include the name of the product when describing the phenomenon.

The neutralization reaction will heat up, and calcium oxide dissolved in water to form calcium hydroxide is also a warming reaction, and both metal and acid reactions are. It is enough to memorize these in junior high school chemistry. Precipitation!

Carbonate precipitates with magnesium, barium, calcium, manganese, zinc, silver, and ferrous ions. Calcium sulfate, silver sulfate is slightly soluble, barely precipitated, and barium sulfate is a precipitate. Silver chloride is a precipitated barium sulfate and silver chloride is insoluble in either water or acid, nitrate does not precipitate.

Alkalis are soluble in potassium, sodium, barium, and ammonium. The rest is insoluble. In the order table of metal activity, the pre-hydrogen metal reacts with the acid to produce hydrogen, and the marble limestone reacts with the acid to produce carbon dioxide.

If you don't have much content in junior high school chemistry, I don't mind if you buy a reference book that is synchronized with the textbook, and many of the books summarize it better.

The general reaction is an exothermic reaction, and individual endothermic reactions. Just memorize what you absorb heat. Like precipitation, you can summarize it yourself and ask the teacher, and the teacher has induction.

Decomposition reaction: There is a reaction in which two or more substances are generated.

h2o---h2 + o

h2o2---h2o +o2

h2co3---h2o +co2

.Wait a minute. Chemical reaction lead reed: A reaction in which two or more substances react to produce one substance. h2+o2--h2o

s+o2---so2...Wait.

Displacement reaction: A single element reacts with a compound to form an anti-locust belt of another element and another compound. cuo+h2---cu+h2o

Metathesis reaction: A reaction in which two compounds exchange components with each other to produce two compounds. hci+naoh---naci+h2o

Neutralization reactions also belong to metathesis reactions.

Chemical reaction (similar to a+b=c).

Graded reaction (similar to c=a+b).

The neutralization of the anti-source of the complex decomposition reaction (file splitting a+b=c+d) should belong to metathesis.

These are the three types that should be used in junior high school.