Experimental activity 2 What are the experimental conclusions of the laboratory production of carbon

1) When producing carbon dioxide, there are certain requirements for drugs, and sodium carbonate cannot be selected for solids, because it reacts too quickly with acid, and blocks of marble or limestone are generally selected; The liquid is generally dilute hydrochloric acid, and concentrated hydrochloric acid is not selected, because concentrated hydrochloric acid has strong volatility, so that the prepared carbon dioxide is not pure, and sulfuric acid cannot be selected, because when sulfuric acid reacts with calcium carbonate, the calcium sulfate generated is slightly soluble in water, and when a large amount of calcium sulfate is generated, calcium sulfate becomes a solid precipitate and adheres to the surface of the marble, thereby preventing the further progress of the reaction, so calcium carbonate and dilute hydrochloric acid are used for medicine;

2) The reactants are calcium carbonate and hydrochloric acid, and the products are calcium chloride, water, and carbon dioxide, which are balanced by observation method, and the carbon dioxide is marked with an ascending symbol;

3) The reactants are solid and liquid and do not need to be heated.

4) Because carbon dioxide can be dissolved in water, it cannot be collected by drainage, and the density is larger than that of air and collected by the upward air discharge method

Experimental steps: 1) Install a simple device for producing carbon dioxide according to the drawing.

2) Add about 10 grams of block marble to the Erlenmeyer flask, and plug the rubber stopper with a long-neck funnel and a catheter.

3) The gas outlet tube is put into the gas collection cylinder, and the mouth of the conduit should be at the bottom of the gas collection cylinder.

4) Add an appropriate amount of dilute hydrochloric acid through the long-neck funnel, and gas is immediately generated in the Erlenmeyer flask.

5) After a while, strike a match, put the lit match on the top of the mouth of the gas bottle, if the match goes out quickly, it means that the gas bottle has been filled with carbon dioxide gas, cover the ground glass sheet, and put the mouth of the gas bottle up on the table for later use.

Key points: 1) Laboratory-produced carbon dioxide, if marble is used as raw material, dilute sulfuric acid cannot be used. Because the calcium carbonate produced is a slightly soluble substance, it wraps around the surface of the marble, so that the acid cannot come into contact with the marble, thus aborting the reaction.

2) The laboratory can use the Qipu generator to produce carbon dioxide, so that it can be used at any time.

3) The drainage method can also be used to collect carbon dioxide gas, but the liquid in the tank is best to use saturated sodium bicarbonate solution, which will not cause carbon dioxide loss.

1.Pay attention to air tightness (step 2) to prevent outside gases from entering, resulting in impure carbon dioxide!

2.The mouth of the catheter should be at the bottom of the bottle, because the specific gravity of carbon dioxide in the air is different, so it should be at the point!

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

Solution: (1) Memorize common experimental instruments;

2) airtightness of the slave device;

3) according to the nature of carbon dioxide;

4) Carbon dioxide reacts with sodium hydroxide solution, causing the pressure in the bottle to become smaller

1) Fill in the names of the reactants in device A in parentheses on the figure, dilute hydrochloric acid, marble

2) In device A, the function of the test tube A is to seal or prevent air leakage

3) In device b, carbon dioxide and water form carbonic acid, so the experimental phenomenon is that the purple litmus test solution turns red; After the reaction, the Erlenmeyer flask in device B is placed on the asbestos net, the alcohol lamp is lit to heat slightly, and the carbonic acid is decomposed, so the phenomenon seen is that the liquid changes from red to purple, indicating that the literal expression of the phenomenon is: carbonic acid.

Heating. Carbon dioxide + water

4) After the C device is filled with carbon dioxide, remove the flask, plug the tube with the balloon and the stopper of the rubber tip dropper containing the sodium hydroxide solution, squeeze the dropper and drop into the sodium hydroxide solution, after oscillation, the carbon dioxide reacts with the sodium hydroxide solution, and the observed phenomenon is that the balloon is expanded, and its original cavity is reduced because the carbon dioxide is easily soluble in sodium hydroxide

Therefore, the answer is: (1) hydrochloric acid; limestone or marble; (2) Seal or prevent air leakage; (3) Purple litmus solution turns red; The liquid turns from red to purple; Carbonic acid.

Heating. carbon dioxide + water; (4) balloon inflatation; Carbon dioxide is easily soluble in sodium hydroxide, which reduces the gas in the bottle

Comments: Test points for this question: Laboratory preparation method of carbon dioxide; the chemical properties of carbon dioxide; Write chemical equations, verbal expressions, ionization equations

Test Center Comments: This question is a brief examination of the laboratory preparation method of carbon dioxide, which involves the preparation and collection, and the identification and properties of carbon dioxide

Laboratory made dioxide, God of Dioxide, let carbon.

The principle of CaCO3+2HCl=CaCl2+H2O+CO2

The laboratory verifies the principle of carbon dioxide: Ca(OH)2 + CO2 = CaCO3 + H2O

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

Solids and liquids react at room temperature.

Answer C analysis: A. According to the reaction conditions, the reaction speed is moderate, the operation is convenient, and it is easy to collect;

b. Calcined limestone is complex to operate, and it is not easy to collect gas and solve problems;

c. According to the reaction conditions, the prepared gas is relatively pure, the reaction speed is moderate, the operation is safe and convenient, and it is easy to collect;

d. The reaction of limestone and dilute sulfuric acid will generate hindering substances to continue to react with imitation sock calcium sulfate, analysis and solution

Answer: a. The carbon dioxide gas produced by the charcoal burning in the air is very slow, and it burns violently in oxygen, but the operation is cumbersome, and it can produce carbon monoxide, and it is not easy to collect pure carbon dioxide gas; therefore a is incorrect; Nuclear foci.

B. Calcined limestone is complicated to operate, and it is not easy to collect gas, so B is incorrect;

c. Marble reacts with hydrochloric acid, the reaction speed is moderate, the operation is safe and convenient, and it is easy to collect; Therefore c is correct

d. Dilute sulfuric acid reacts with limestone to generate calcium sulfate, and calcium sulfate slightly soluble in water covers the surface of limestone, hindering the further progress of the reaction, so D is incorrect

Therefore, choose C Comment: This question examines the preparation of gas in the laboratory, and the principle is to pay attention to the following points: the prepared gas should be pure, the reaction is fast, the operation is safe and convenient, and it is easy to collect