Year oxygen was discovered

Answer 1

Oxygen was discovered for the first time by a Swedish Chemist, Carl Wilhelm Scheele, in 1772. Joseph Priestly, an English chemist, independently, discovered oxygen in 1774 and published his findings the same year, three years before Scheele published. Antoine Lavoisier, a French chemist, also discovered oxygen in 1775, was the first to recognize it as an element, and coined its name "oxygen" - which comes from a Greek word that means "acid-former".

There is a historic dispute about who discovered oxygen. Most credit Priestly alone or Both Priestly and Scheele. Experiments:

In 1772, Carl Wilhelm Scheele discovered that red-hot manganese oxide produces a gas. He called the gas "fire air" because of the brilliant sparks it produced when it came in contact with hot charcoal dust. He repeated this experiment by heating potassium nitrate, Mercury oxide, and many other materials and produced the same gas. He collected the gas in pure form using a small bag. He explained the properties of "fire air" using the phlogiston theory, which was soon discredited by Lavoisier. He carefully recorded his experiments in his notes, but waited several years before publishing them.

In 1774, Priestley repeated Scheele's experiments using a 12-inch-wide glass "burning lens", he focused sunlight on a lump of reddish mercuric oxide in an inverted glass container. The gas emitted, he found, was "five or six times as good as common air." (1) In succeeding tests, it caused a flame to burn intensely and kept a mouse alive about four times as long as a similar quantity of air.

Priestley, a big supporter of the phlogiston theory, called his discovery "dephlogisticated air" on the theory that it supported combustion so well because it had no phlogiston in it, and hence could absorb the maximum amount during burning.

E.g. of how Priestley was smarter:

So priestly proved that plants somehow change the composition of the air.

In another celebrated Experiment from 1772, Priestley kept a mouse in a jar of air until it collapsed. He found that a mouse kept with a plant would survive. However, I do not recommend to repeat this experiment and hurt innocent animals.

These kinds of observations led Priestley to offer an interesting hypothesis that plants restore to the air whatever breathing animals and burning candles remove - what was later coined by Lavoisier "oxygen".

In these experiments, Priestly was the first to observe that plants release oxygen into the air - the process known to us as photosynthesis.

B/R,

Vanessa