Understanding the Composition of Air
By the mid-18th century, researchers had discovered around two dozen or so elements and the researchers were not sure how air fit the concept of an element. Nobody was exactly sure what it was and it was observed that air was convertible in several different forms and everyone thought that there were several different varieties of air. The most commonly used method of converting air was to heat it or use it for burning some compound. Scientists were deeply interested in the combustible properties of air because of many new inventions like the steam engine and they wanted to use this element for combustible purposes.
Chemists from England were especially productive because Joseph Black identified carbon dioxide which he referred to as ‘fixed air’ because it could be regenerated into the solids from which it was produced. In 1766 Henry Cavendish produced hydrogen which was named after the Greek words for ‘maker of water’. He did this by burning material in a jar and by cooking it with potash. At that time he called in the poisonous air because it suffocated mice that were placed in the jar with the burnt material. However, the most important discovery was that of oxygen, because it is the most abundant element in the earth’s environment.
The first person to discover oxygen was the Swedish pharmacist Carl Wilhelm Schede. He called it ‘fire air’ because it was the only element which could be incinerated. At the same time, oxygen was also discovered by Joseph Priestly who also demonstrated the life supporting of this gas. Although oxygen has been produced by many chemists before its discovery by Priestly and Schede, they did not recognize it as a separate element. Oxygen makes up nearly 50% of the earth’s outer layer. It is a very rash element and can easily mix with most other elements.
Massive quantities of oxygen can be obtained from the earth’s atmosphere because it constitutes around 21% of the earth’s atmosphere. It can also be produced from water and by heating potassium chlorate. Oxygen is essential for most living orgasms and for most types of combustion. Oxygen is also mixed with acetylene to make an extremely hot flame and is used for as cutting and welding. The fuel used by rockets is made from oxygen and liquid hydrogen. Oxygen is also an essential component of hundreds of thousands of organic compounds which is the reason for its importance for all living things.