Experimental formula for the preparation of oxygen CO2 hydrogen in junior high school to reduce Cu2O

Experimental phenomena of electrolysis of water:

The positive electrode (anode electrode) produces oxygen and gas, and negative hydrogen (father) does not need a formula, as long as you do an experiment in the laboratory under the guidance of the teacher, you will not forget it. In addition, if you read and watch more, you will know it by heart.

Chemistry sometimes can't be opportunistic, but I'll give you a recipe for dissolving acid-base salts.

soluble alkalis potassium, sodium, barium and calcium (micro), nitric acid, potassium, sodium, ammonium salts soluble in water;

insoluble silver chloride in hydrochloride, barium sulfate insoluble in sulfate;

Carbonic acid, phosphoric acid, silicic acid, sulfurous acid, only potassium, sodium, ammonium salts are soluble in water.

With the tune of "Three Disciplines and Eight Attentions", it's fine.

Note: Common acids in junior high school are soluble in water.

There is no need for formulas, as long as you do an experiment in the laboratory under the guidance of the teacher, you will not forget it. In addition, if you read and watch more, you will know it by heart.

Oxygen is produced in the laboratory. There are three ways to do this. One is hydrogen peroxide in manganese dioxide.

as a catalyst. One is that potassium chlorate is heated under the condition that manganese dioxide is used as a catalyst; The other is potassium permanganate.

Thermal decomposition. Carbon dioxide is prepared in the laboratory by reacting it with marble or limestone and dilute hydrochloric acid. Hydrogen is prepared in the laboratory and reacted with zinc particles and dilute sulfuric acid or dilute hydrochloric acid. The chemical equation is.

Junior High School Chemistry - Carbon dioxide produced in the laboratory.

The three chemical reactions (reaction principles) used to produce oxygen in the laboratory are all decomposition reactions in which one substance produces two or more other substances;

The chemical reaction formula (reaction principle) used to produce carbon dioxide in the laboratory is a metathesis reaction in which two compounds exchange components with each other to form two other compounds

The chemical reaction formula of hydrogen prepared in the laboratory is a reaction in which an element reacts with a compound to produce another element and another compound, which belongs to the displacement reaction;

Therefore, the type of reaction that is not involved is chemical reaction; So choose A

Junior High School Chemistry - Carbon dioxide produced in the laboratory.

Be sure to give points! I'm in my third year of junior high school.

Oxygen is produced in the laboratory (potassium permanganate is heated).

Equipment: iron frame, large test tube, catheter, single-hole rubber stopper, sink, water, gas collection bottle, cotton, alcohol lamp, match, glass sheet.

1。Connect the device and check the air tightness.

2。After checking that it is correct, potassium permanganate is added to the test tube, a ball of cotton is stuffed at the mouth of the test tube, and the mouth of the test tube is slightly inclined downward and fixed on the iron frame.

3。Light an alcohol lamp, preheat it first, then heat it to the drug centrally, and place the catheter in the water4. The gas collection bottle is filled with water, and after the initial bubbles are evenly placed in the catheter, oxygen is collected with drainage gas collection5.

When air bubbles are released at the mouth of the gas collector cylinder, cover the glass sheet under water, and the gas collector cylinder is placed on the table6. Now remove the catheter from the water and extinguish the alcohol lamp.

7。I finish it and arrange the equipment.

CO2 (marble and dilute hydrochloric acid) is produced

Equipment: Erlenmeyer flask, double-hole stopper, separating funnel, catheter, gas collection cylinder, glass piece 1. Connect the device and check the air tightness.

2。After checking that there are no errors, add dilute hydrochloric acid to the separating funnel and marble 3 to the Erlenmeyer flask. Open the piston of the separating funnel to allow hydrochloric acid and marble to react to release CO2, which is collected by the upward exhaust method4. Burn a match and put it on the mouth of the bottle and extinguish it, indicating that the collection is full.

5。I finish it and arrange the equipment.

There is an eight-character mantra for the operation of heating and producing oxygen in the laboratory:

Even the check-and-install fixed-point retraction and extinguishing can also be homophonic into:

Even the tea house charges interest at a fixed point, so that it is easy to remember.

1 Connection: Connecting device.

2. Check: Check the air tightness.

3 packs: Load the medicine.

4. Fixed: fixtures.

5 o'clock: Light the alcohol lamp.

6. Collect: Collect gas.

7 Shift: Remove the catheter.

8 Off: Extinguish the alcohol lamp.

Attention should be paid to the operation: The test tube is fixed on the iron frame, and the mouth of the test tube is slightly inclined downwards to avoid the presence of water affecting the gas production and easy to burst the test tube; The iron clamp is clamped at about 1 3 places away from the nozzle, which is conducive to the heating of the drug; When heating the test tube, first make the test tube evenly heated, and then fix the heating, and pay attention to the use of alcohol lamp external flame, which can avoid the explosion of the test tube caused by uneven heating, and make full use of the heat source; Oxygen should be collected by draining and taking air, and the air duct should be withdrawn from the tank before the alcohol lamp should be extinguished. This prevents suction, which can cause cold water to enter the hot tube and cause the tube to burst.

Operations to produce carbon dioxide:

1. Connecting device.

2. Check the air tightness.

3. Load solid medicines.

4. Add dilute hydrochloric acid.

5. Collect gases.

6. Test gas.

7. Precautions for full inspection: first install marble, and then add dilute hydrochloric acid;

The lower end of the long neck funnel of the assembled instrument should be deep below the liquid level; When collecting with downward exhaust air, the catheter should extend into the bottom of the gas collection cylinder; When it is full, the burning wooden strip should be placed at the mouth of the gas collection cylinder.

Junior High School Chemistry - Carbon dioxide produced in the laboratory.

Oxygen: 2kmNO4 (potassium permanganate) is heated to obtain KMNO4 (potassium manganate) Mno2 (manganese dioxide) O2 (oxygen).

2kcl3 (potassium chlorate) is heated to obtain 2kcl (potassium chloride) 3o2 (oxygen) hydrogen: HCL (hydrochloric acid) x (a certain metal) = XCL (chloride a certain metal) H2 (hydrogen).

Carbon dioxide: 6HCl (hydrochloric acid) 2CAC3 (calcium carbonate) 2CACl3 (calcium chloride) 2H2O (water) 2CO2 (carbon dioxide.

Junior High School Chemistry - Carbon dioxide produced in the laboratory.

Hydrogen is produced in the laboratory.

zn+2hcl==zncl2+h2↑

zn+h2so4==znso4+h2↑

Oxygen is produced in the laboratory.

2h2o2=mno2=2h2o+o2↑

2kclo3=mno2 δ=2kCl+3O2 Laboratory-produced carbon dioxide.

CaCO3+2HCl==CACl2+H2O+CO2 Math Tutoring Group will answer for you, please correct if you have mistakes, please ask if you don't understand.

If there is no problem, just take it, and I wish you progress in your studies and go to the next level! (*

Carbon dioxide production:

Calcium carbonate and hydrochloric acid.

Equation CaCO3 +2HCl = CACl2 + H2O + CO2

Put marble into an Erlenmeyer flask, add dilute hydrochloric acid to the Erlenmeyer flask (if you use a long-neck funnel, the lower end of the nozzle should be under the liquid surface, but generally you can directly use a single-hole rubber stopper to connect a trachea), use the upward air exhaust method to collect gas, fill it with a burning wooden strip at the mouth of the bottle, and cover it with a coverslip.

Oxygen production: Manganese dioxide catalysis.

Generally, you don't need to do this

Load potassium permanganate into a large test tube, the bottom of the test tube is higher than the mouth of the test tube, and plug cotton at the mouth of the bottle, plug a single-hole rubber stopper with a catheter, and fix it on the iron frame. The other end of the catheter is immersed in the sink. Light the alcohol lamp, move it back and forth to preheat, and then fix the heating, and after the bubbles coming out of the catheter mouth in the sink are stable and continuous, the oxygen is collected by the drainage method and tested with a sparkling wooden strip.

MnO2 principle; 2H2O2====2H2O+O2 Precautions: 1The separating funnel can be replaced with a long-neck funnel, but its lower end should be deep below the liquid level to prevent the generated gas from escaping from the long-necked funnel.

2.Air tightness check. Close the water stop clip, open the piston of the separating funnel, add water to the funnel, and the water surface does not continue to fall, indicating good air tightness.

3.When filling medicines, fill solids first and then liquids. It is collected by the drainage method or the upward exhaust method.

Principle: CaCO3 +2HCl = CaCl2 + H2O + CO2

Precautions, first install marble, then add dilute hydrochloric acid, assemble the instrument long neck funnel lower end of the nozzle to go deep below the liquid level, with upward exhaust air hair collection, the catheter should be extended into the bottom of the gas collection cylinder, when the inspection is full, the burning wooden strip should be placed at the mouth of the gas collection cylinder.

1. Oxygen (O2) preparation method.

Steps: (1) Check the air tightness (2) Fill the medicine (3) Heat (4) Collect (5) Move.

Problems that are often paid attention to in the experiment: (1) the alcohol lamp is heated with an external flame (2) the test tube is clamped to remove the air duct in the water (6) the alcohol lamp is extinguished at 1 3 places away from the test tube mouth (3) the test tube mouth is slightly inclined downward (4) the air duct extends into the rubber plug 2-3 cm (5) the catheter is removed first, and then the alcohol lamp is removed.

Hello! Sodium peroxide.

Chemical properties: sodium peroxide is not a basic oxide, but it can also react with water, carbon dioxide, and acid, and oxygen is released during the reaction, and the chemical equations are:

2na2o22h2o

4naoho2↑

2na2o22co2

2na2co3o2