Advice 1: How to get calcium carbide

Probably everyone remembers their merry school days. And especially the fun we had at the time of carrying out repairs to the school building, when workers, besides all the other equipment and brought in their own generator and a barrel of acetylene, carbide of calcium. Those days were a nightmare for workers in all schools, starting from the Director to the cleaning lady because the carbide of calcium is the favorite pastime of scholars. No account of a broken toilet in the school toilets. Here he is carbide of calcium.
You will need
  • The crucible (preferably graphite), graphite electrode, calcium oxide (quicklime), coke, a source of current.
The principle of obtaining this substance is that the oxygen atom in a molecule of oxide of calcium is replaced by two carbon atoms. In industry this is achieved by calcining the mixture of coke and quicklime at a temperature of approximately 2000 degrees Celsius. But, a little bit of this wonderful substance can be obtained, and artisanal. Mix quicklime and coke in the ratio of one to one by weight of the mixture and place in the crucible. Next, take the two wires from the power source, one hook to the crucible, and the second touches the graphite electrode and the power supplied.
After that close the circuit, i.e., immerse the electrode in the mixture, due to the fact that in the mixture there is a carbon between the electrode and the blend creates an electric arc, current flows, the mixture is heated and melted in places.Try it melted over the entire area. After cooling the mixture, that is, in some places the melt should contain the carbide of calcium. If the dip of the melt in the water it produces a combustible gas (acetylene), the experience was a success.
An electric arc is a phenomenon very bright, so use dark glasses to protect your eyes.
Useful advice
When mixing, do not have to consider the molar mass, just try to take coke in excess, the fact that in the process the excess carbon will burn in air. The more current the better, but without fanaticism.

Advice 2: How to obtain acetylene from calcium carbide

Acetylene is the simplest representative of a class of alkynes, has the chemical formula C2H2. A colorless gas that is combustible in mixture with air is explosive. Due to the presence of a triple bond in its molecule, it is highly active from a chemical point of view, easily enter into reactions of addition. When burned, emits large amount of heat that can be used, for example, many well-known "acetylene burner". How to synthesize?
How to obtain acetylene from calcium carbide
The storage of acetylene should take into account its features. For example, it is impossible to keep in tanks with bronze valve, because the gas reacts with the copper included in the composition of bronze, forming a highly explosive substance – acetylene copper.
The oldest, time-proven method of producing acetylene is the reaction of carbide of calcium with water. Probably, many boys amused themselves by throwing pieces of carbide in a puddle, immediately began a furious hiss, carbide, literally, "boiled", disappearing in the eyes, and the air distinctly smelled something sharp, "sharp". This reaction proceeds thus:
CaC2 + 2Н2О = C2H2 + CA(Oh)2, to ensure that it was not too heavy, you can use plain water and a saturated solution of sodium chloride, for example.
If this experience is planned to be shown in chemistry class, you should pick up the reaction flask of a suitable size. If it is too small, forming upon dissolution of the carbide foam can be "thrown" by the pressure of the acetylene in the outlet tube and then into the receiving vessel. In the case of too large a bulb will have a long wait until the acetylene formed does not displace all air from the device.
Water, and better saturated solution of sodium chloride should be added in a flask with pieces of carbide slowly, drop by drop by adjusting the reaction speed, avoiding it flowed too violently.
Useful advice
Acetylene is used in a variety of areas. For example, as raw materials for the production of a number of chemicals (acetic acid, plastics, some aromatic hydrocarbons, certain types of synthetic rubber, ethyl alcohol, etc.). Based on it synthesize some very strong explosives used as initiators, i.e. for detonation. Widely used in cutting and welding of metals in the production of bright light in the Autonomous lamps.
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