Sure you know that oxygen is the gas that people and animals need to breathe.
Discovering oxygen
Although oxygen is part of the air, it took chemists a long time to discover it. This only happened at the end of the 18th century.
The discovery of oxygen was hindered by several misconceptions. First, chemists believed that the air was homogeneous and a single chemical element. Secondly, they had a false theory explaining the combustion processes. It was believed that combustion was the result of the release of a fictitious substance, phlogiston, which was believed to be present in all combustible substances.
Over time, however, in studying the combustion processes in closed flasks, chemists noticed that the mass of air is reduced by one fifth, and concluded that the air consists of two parts - supporting combustion and not supporting. Indeed, as we know today, the air consists mainly of nitrogen (of which there is almost 80%) and oxygen (of which just over 20%). The next step for chemists was to release oxygen in the decomposition of oxides and acids and to study its properties. Although Sweden's Sheele and Englishman Priestley were the first to conduct such experiments, they never realized that they had discovered a new element. Only the French chemist Lavoisier was able to understand everything.
He also gave a name to a new element - "oxygen", or in Russian - oxygen. This name was given to the element because at that time it was obtained by decomposition of acids, and Lavoisier mistakenly decided that oxygen is present in any acid. The main element that gives acids their properties is hydrogen, and oxygen is not available in all acids, but the name given to it in the 18th century has remained behind oxygen.
Oxygen is not only needed for life but also exists because of it
When it was discovered that oxygen was needed for breathing, scientists were even frightened at first. After all, over time, oxygen in the atmosphere will run out, and then everyone will die! However, it was soon discovered that plants absorb carbon dioxide and produce oxygen under the influence of light. Moreover, it is now known that before life in the atmosphere there was no oxygen gas at all. This is not surprising, because oxygen is a very active chemical element. So even before the Earth had formed, all oxygen had been combined with other chemical elements.
The atmosphere filled with oxygen did not appear at once. Although life was born a long time ago, the first life forms did not need oxygen and did not produce it. About 3.5 billion years ago, the first cyanobacteria appeared, which mastered the process of photosynthesis. The gaseous oxygen, which was released at the same time, was a by-product. However, the activities of these bacteria have led to global and huge changes. For billions of years, the oxygen emitted by bacteria reacted with substances dissolved in the ocean, with gases in the atmosphere and with rocks. But over time, they all oxidized and oxygen began to accumulate in the atmosphere. And only after that, instead of anaerobic life forms living in an oxygen-free environment, many aerobic forms appeared in the world, which, on the contrary, began to use oxygen for breathing.
Almost everything burns down in pure oxygen
The combustion process we are used to is the combination of various substances with oxygen in the atmosphere. Oxygen is the second most active nonmetal after fluorine, so it is very active in chemical reactions. And if many substances easily ignite even in normal air, where only 20% of oxygen is present, what happens if you take pure, concentrated oxygen?
In pure oxygen, substances that usually do not burn or burn well, such as iron, are perfectly combusted
It'll burn even faster if you use liquid oxygen.
Ozone is even more chemically active than regular oxygen. The reason is that the bonds in the triple molecule are less strong and the individual atoms are easily detached from it. For the same reason, under normal conditions, ozone spontaneously turns into oxygen over time, although it can be stored for a long time at low temperatures.
Because of its high activity, ozone reacts with substances with which simple oxygen, such as silver, does not react. Also, with many substances that need to be ignited to react with oxygen, ozone reacts at normal temperatures.
In more or less significant concentrations, ozone is poisonous and dangerous to living organisms. But this property of ozone, strange as it may seem, is very useful. Ozone is easily obtained from oxygen with ozonators and used to disinfect water, rooms, etc. Ozone effectively kills all microorganisms, mold, and its use is not as dangerous as the use of chlorine and other toxic substances. The reason is that over time, ozone will spontaneously turn into oxygen and its toxic properties will disappear.