At the beginning of studying such a subject as chemistry, the most interesting thing is to conduct experiments, and if these experiments are also accompanied by a small spectacular explosion, then it is generally difficult to contain the delight. At the word "explosion" various associations arise, and one of them is explosive gas. What is its formula, where it is used and, of course, the safety rules when working with it - the main questions of the article.
Composition
It actually contains hydrogen mixed with oxygen. In a certain proportion of 1: 2, they form explosive gas. Its formula will look like this: 2H2+O2.
The slightest spark with an energy of 14 mJ or heating to 510 °C (the burning temperature of a match is over 700 °C) is enough to cause a reaction between them, which is accompanied by the release of a large amount of energy and an explosion.
And the result of this reaction is ordinary water. It is not for nothing that the gas is called hydrogen, that is, giving birth to water. Butit is worth introducing, for example, spongy platinum into the mixture, and there will be no explosion, but the usual combustion process will go on.
Another name for the gas mixture - Brown's gas, got its name in honor of the inventor who developed a car that runs on the decomposition products of water by electrolysis. And the gas formula in chemistry looks like this: HHO.
Discovery history
The fact that during a chemical reaction between acids and some metals a gas is formed, which is very flammable, is mentioned in treatises of the 16th century. It was called "flammable air". But it was possible to collect it in its pure form, study the properties and describe them only in the second half of the 18th century. So, the chemist A. Lavoisier, conducting experiments in 1784, concluded that a gas is a simple substance consisting of only one type of atoms.
And the famous chemist and physicist G. Cavendish experimentally managed to determine that oxygen + hydrogen as a result of instantaneous combustion gives water. By the way, one of the laboratories in Cambridge is named after him precisely because he was able to determine the qualitative composition of water. The Latin name for hydrogen Hydrogenium comes from two words "hydro" - water and "gennao" - birth, that is, it (as in the Russian version of the name of the element) describes its main property - to give birth to water.
Application
Where is it used?
Interest in such an alternative fuel as hydrogen is showing more and more. But the first developer to introduce a car powered by suchfuel, was the concern Toyota. However, his FCHV SUV remained an exhibition copy, they did not mass-produce it. Interest in hydrogen engines has not disappeared, so many manufacturers continue to invest heavily in the introduction of such an engine.
Explosive gas, more precisely, hydrogen with oxygen supply, is used for welding and brazing of metals in difficult conditions, such as tunnels and mines, sewers and installation wells, when there is simply no place for hydrocarbon cylinders. The combustion temperature of the mixture is approximately 2235 ° C, and the combustion products are absolutely safe for human he alth. The hydrogen burner has found its application in jewelry and prosthetics, it is used to process glass products, plates of expensive metals of different thicknesses and more.
Enemy of the miners
Sometimes the term "explosive gas" is erroneously used in relation to methane. The ability of this hydrocarbon to accumulate in the voids of rocks and when mixed with air becomes explosive, it is similar to a mixture of real gas, but this is where their similarity ends. The formula for a gas in chemistry looks like this: CH4.
The most dangerous concentration in the atmosphere of methane is 9.5%, but under different conditions it can vary from 5 to 16%. At a higher concentration, the gas will simply burn. Both a spark and an open fire can provoke an explosion. To control the concentration of methane in the air, the miners took a canary with them, and they knew that while the song of a little friend was heard, they could work calmly. Butas soon as the bird was silent, it meant that trouble was close.
At the beginning of the 19th century, songbirds were replaced by a Davy miner's lamp, and today the control is carried out by an automatic system, but even this does not make the work of miners completely safe. Explosions sometimes happen even now. Here he is so terrible - "firedamp".
Profit for the dishonest
How much happiness brings balloons filled with helium. There are few children who can resist a multi-colored miracle. Yes, and the holidays are now not complete without helium balloons, which immediately soar up, it is worth letting go of the thread for a second.
Today, a helium balloon costs decent money, and some negligent sellers decide to save money. After all, not only helium, hydrogen can make the ball fly. Acetylene is also lighter than air. But is such savings really safe for the customers themselves?
Recently, more and more news about balloon explosions has been heard:
- May, 2012 - Yerevan;
- October, 2017 - Kuzbass;
- October, 2017 - Kemerovo.
These are just three known cases, in one of them, namely at a rally in Yerevan, the balloons were filled with hydrogen, which could go outside and accumulate in the air, mixing with oxygen. And we know that such a mixture in a certain proportion is called explosive gas. People suffered in this tragedy.
