THE DISCOVERY OF OXYGEN

The Discovery of Oxygen

The Discovery of Oxygen

Introduction

In the mid 18th century, people thought air was inert -- that it didn't take part in combustion. We know that the oxygen in air reacts with other materials when they burn. But 18th-century chemists thought burning materials were simply releasing an invisible fluid called phlogiston, which caused heating. No one supposed burning had anything to do with the air itself. They didn't know the culprit was oxygen, which makes up one fifth of air. Oxygen was finally pinned down as a separate element by three people in the 1770s: an English cleric named Priestley; the French chemist Lavoisier; and a Swedish pharmacist named Scheele(Cook Lauer 1998).

Oxygen

Oxygen had been produced by several chemists prior to its discovery in 1774, but they failed to recognize it as a distinct element. Joseph Priestley and Carl Wilhelm Scheele both independently discovered oxygen, but Priestly is usually given credit for the discovery. They were both able to produce oxygen by heating mercuric oxide (HgO). Priestley called the gas produced in his experiments 'dephlogisticated air' and Scheele called his 'fire air'. The name oxygen was created by Antoine Lavoisier who incorrectly believed that oxygen was necessary to form all acids(Emsley 2001).

Oxygen is the third most abundant element in the universe and makes up nearly 21% of the earth's atmosphere. Oxygen accounts for nearly half of the mass of the earth's crust, two thirds of the mass of the human body and nine tenths of the mass of water. Large amounts of oxygen can be extracted from liquefied air through a process known as fractional distillation. Oxygen can also be produced through the electrolysis of water or by heating potassium chlorate (KClO3).

Oxygen is a highly reactive element and is capable of combining with most other elements. It is required by most living organisms and for most forms of combustion. Impurities in molten pig iron are burned away with streams of high pressure oxygen to produce steel. Oxygen can also be combined with acetylene (C2H2) to produce an extremely hot flame used for welding. Liquid oxygen, when combined with liquid hydrogen, makes an excellent rocket fuel. Ozone (O3) forms a thin, protective layer around the earth that shields the surface from the sun's ultraviolet radiation. Oxygen is also a component of hundreds of thousands of organic compounds(Emsley 2001).

Discovery Of Oxygen

The discovery of Oxygen was credited to Priestley in 1774 AD. However in a paper looking into Alchemy, by Richard Brzezinski, an expert in the history of science and Zbigniew Szydlo, a chemistry lecturer, published in the authoritative magazine History Today credit the discovery of Oxygen to a Polish alchemist called Michael Sendivogius who found that heated saltpeter produced "the elixir of life" and who, in 1604, described his experiments in a book regarded as so authoritative that it found its way into every major scientific library in Europe. They say that Priestley, would surely have had access to it. Cornelis Drebbel a Dutch inventor employed by the King ...