This group of substances includes oil and methane, natural gas. Their diversity is great. Speech, of course, about hydrocarbons. These are at the same time one of the most widespread and most demanded substances by mankind. What are they? It is worth remembering what chemistry taught in grade 9.
Hydrocarbons
This class of substances combines a variety of compounds, most of which have long been successfully used by humans for their own purposes. This is due to the fact that carbon very easily forms chemical bonds, especially with hydrogen, which is why such a variety is observed. Without this, life in the form in which we know it would be impossible.
Hydrocarbons are substances consisting of two elements: carbon and hydrogen. Their molecules can be not only linear, but also branched, and also form closed cycles.
Classification
Carbon forms four bonds, and hydrogen one. But this does not mean that their ratio is always 1 to 4. The fact is that between carbon atoms there can be not only single, but also double, as well as triple bonds. By this criterion, classes of hydrocarbons are distinguished. In the first case, these substances are called limiting (or alkanes), and in the second - unsaturated or unsaturated (alkenes and alkynes for two and three bonds, respectively).
Another classification involves consideration of the molecule. In this case, aliphatic hydrocarbons are distinguished, the structure of which is linear, and carbocyclic, in the form of a closed chain. The latter, in turn, are divided into alicyclic and aromatic.
In addition, hydrocarbons are often polymerized - the process of joining the same molecules to one another. The result is a completely new material, not similar to the base. An example is polyethylene made from simple ethylene. This is only possible when it comes to unsaturated hydrocarbons.
Structures, which also belong to the class of unsaturated ones, can also add new atoms other than hydrogen with the help of their free radicals. In this case, other organic substances are obtained : alcohols, amines, ketones, esters, proteins, etc. But these are completely separate topics in chemistry.
Examples
Hydrocarbons are a huge variety of substances, even taking into account the classification. Nevertheless, it is worth briefly listing the names of the compounds included in this numerous class.
- Limit hydrocarbons are methane, ethane, propane, butane, pentane, hexane, heptane, etc. The first and third names are probably familiar even to those who are not particularly friends with chemistry. So called fairly common types of gases.
- The class of alkenes (olefins) includes ethene (ethylene), propene (propylene), butene, pentene, hexene, etc.
- Alkynes include ethine (acetylene), propine, butine, pentin, hexine, etc.
- By the way, double and triple bonds may not be single. In this case, such structures belong to alkadienes and alkadins. But you should not go too deep.
- As for hydrocarbons whose structure is closed, they have their own names: cycloalkanes, cycloalkenes and cycloalkines.
- The names of the former: cyclopropane, cyclobutane, cyclopentane, cyclohexane, etc.
- The second class includes cyclopropene, cyclobutene, cyclopentene, cyclohexene, etc.
- Finally, cycloalkines not found in nature. They tried to synthesize them for a very long time and for a long time, and this was possible only at the beginning of the 20th century. The cycloalkine molecules are composed of at least 8 carbon atoms. With less, the connection is simply unstable due to too much voltage.
- There are also arenas (aromatic hydrocarbons), the simplest and most common representative of which is benzene. Also in this class are naphthalene, furan, thiophene, indole, etc.
The properties
As already mentioned above, hydrocarbons are a huge amount of a variety of substances. Therefore, talking about their common properties is somewhat strange, because there are simply none.
Exceptionally, the composition may be considered the same feature for all hydrocarbons. And also the fact that at the beginning of each row, as the number of carbon atoms increases, there is a transition from a gaseous and liquid form to solid.
There is another similarity: all hydrocarbons have good combustibility. At the same time, a lot of heat is released, carbon dioxide and water are formed.
Natural springs
Like other minerals, some hydrocarbons are located in the form of deposits and reserves in the earth's crust. In particular, they make up most of the gas and oil. This is clearly seen in the processing of the latter: a huge amount of substances are released in the process, most of which relates specifically to hydrocarbons. Gas and generally 80-97% usually consists of methane. In addition, methane is formed during the decomposition of organic waste and residues, so its receipt does not pose a serious problem.
Other hydrocarbon sources are laboratories. Those substances that are not found in nature can be synthesized from other compounds using chemical reactions.
Using
Hydrocarbons play a huge role in the modern life of mankind. Oil and gas have become very valuable resources, because they serve as fuel and energy. But these are not the only ways to use compounds from this class. Hydrocarbons are literally everything that surrounds people in everyday life. Using polymerization, it was possible to obtain new materials from which various types of plastics, fabrics, etc. are made. Kerosene, solvents, paints and varnishes, paraffins, asphalt, tar, bitumen, and this is not counting the main products of oil refining - gasoline and diesel fuel.
The value of these substances is enormous. Both unsaturated and saturated hydrocarbons are hundreds and thousands of things that every person is used to and cannot do without them in the simplest situations. It is extremely difficult to refuse to use them, even taking into account the fact that oil and gas reserves are running out, analysts predict. Already, mankind is actively searching for alternative energy sources, but not one of the options has yet shown the same efficiency and universality as hydrocarbons.