What was the discovery of oxygen?

Although humans have been breathing oxygen in the air since their inception, it was not until the 18th century that the existence of oxygen was recognized. Of all the elements discovered so far, oxygen is the most important, and its discovery once sparked a revolution – the chemical revolution; At the same time, oxygen is also the most controversial element, and its discovery has also sparked many debates. Who discovered oxygen?

Who was the first to discover oxygen? Is the discovery of oxygen an event or a process? The answers to these questions are not as straightforward as they are described in chemistry textbooks.

The history of the discovery of oxygen" theory "fire particles" said: In 1663, the famous English scientist Robert Boyle conducted calcining experiments on several metals. He believed that the weight gain of metal calcination is that the fire particles combine with the metal through the wall of the container and make the metal heavier.

According to Boyle, fire is a real material element composed of particles of fire with weight. Therefore, this weight gain is due to the fact that the fire particles penetrate through the wall of the vessel and penetrate into the metal body during calcination.

Namely: metal + fire particles metallic ash. This is the fire particle theory.

Phlogiston" said: In 1702, the German scholar Olg Brown Ernst S. Starr founded the "phlogiston" theory. The "phlogiston" theory holds that all chemical changes related to combustion can be attributed to the process by which an object releases and absorbs phlogiston.

He proposed that all combustible substances contain phlogiston, and phlogiston is the element of combustion. He also believed that during the calcination, phlogiston escaped, leaving metal ash. If charcoal containing a large amount of phlogiston is mixed with metal ash and heated, the metal ash can be combined with phlogiston to form metal.

Namely: metal-phlogiston metallic ash. This is phlogiston theory.

3."Oxidation" said: In 1774, the French chemist Lavoisier discovered in experiments:

A layer of metallic ash forms on the surface of tin and lead in a closed container after heating, and the total mass of the objects in the container does not change after heating, but the mass of tin and lead increases, while the air decreases. He realized that the essence of this phenomenon was that the metal reacted with certain components in the air. Later, Lavoisier learned and repeated Priestley's experiments, and found that the composition of the air combined with the metal was oxygen.

In 1777, Lavoisier formally proposed the theory of oxidation: the essence of combustion is the combination of an object and oxygen.

It was precisely because of the metaphysical mechanistic view of nature that Priestley fell into the quagmire of "phlogiston theory" and could not extricate himself. Although he had gotten the oxygen in his hands, it did not bear fruit; Lavoisier, on the other hand, was able to take the oxygen from Priestley's hands and reinterpret the combustion, making a major discovery in the field of chemistry. This is no accident.

Lavoisier's superiority compared with Priestley, Scherer and others lies in the fact that he truly adhered to the materialist viewpoint, attached importance to scientific experiments and quantitative research, and critically examined all old concepts and theories, dared to break through all traditional ideas, and had the courage to eliminate the biggest obstacle to the discovery of oxygen - the "phlogiston theory", so he became the person who really discovered oxygen in the history of chemical development.

When it comes to how oxygen comes from, you may think of a series of chemical formulas for making oxygen that you learned in chemistry class in middle school.

What electrolyzed water, potassium permanganate, hydrogen peroxide or something.

However, the most important thing about oxygen is the photosynthesis of plants.

Photosynthesis reactive.

When light shines on the leaves of plants, small cells begin their own photosynthesis, absorbing carbon dioxide from the air and converting it into oxygen and releasing it into the air.

Today, 20% of the Earth's oxygen comes from the rainforests of South America, which are also known as the lungs of the Earth.

Amazon rainforest.

Needless to say, the importance of oxygen is well known, and without oxygen, most life on the planet would face death.

China has also made a lot of efforts to supply oxygen, and in 40 years we have created a green forest the size of a tropical rainforest. The earth also has a second lung.

Through observations of the distant universe, scientists finally came to a conclusion: the oxygen element in the universe was formed 700 million years after the universe was large. In the infinite universe, oxygen is actually a very widespread existence.

People often say that oxygen is produced by plants, but in fact it is not like this, plants on the earth only reduce carbon dioxide in the air to oxygen through photosynthesis and release oxygen from the water absorbed by plant roots. If oxygen weren't always present on Earth, plants wouldn't be able to release oxygen.

As for how oxygen is produced on Earth, the question is actually the simplest: the primordial nebula that formed the solar system began as a nebula rich in hydrogen and many other elements, and in the process of forming the sun and various planets, hydrogen and oxygen reacted under suitable conditions to form water, and then formed ice in a vacuum and low temperature environment and was preserved.

In the early primitive solar system, it should be said that almost all primitive planets were composed of ice meteorites, but in the long years, various collisions between primitive planets made the material rich in each planet different, the closer the planet to the sun, under the radiation of the sun, the ice on the planet will quickly melt, or be evaporated into space, such as Mercury and Venus, due to the radiation of the sun, the water on the planet is evaporated into space, It is then blown by the solar wind to the Earth's orbit and is captured by the Earth's gravitational pull.

The orbit in which the earth is located is just enough to make the ice on the earth melt without being evaporated by the sun's radiation, therefore, this also provides conditions for the production of oxygen on the earth, the ice buried deep in the interior of the planet melts on the surface of the planet under the irradiation of the sun and the internal heat of the earth's core, and the sun's radiation makes the water on these primitive planets evaporate to the sky above the planet, but fortunately the gravitational pull of the earth just right to bind the water that evaporates into the air, thus forming clouds. And those primitive clouds will gradually decompose into hydrogen and oxygen and other gases under the bombardment of solar rays, thus forming the most primitive atmosphere, in this case, the occasional formation of life on the earth has exacerbated the ,... of increasing oxygen on the earthIt's as simple as that.

About 98% of the oxygen in the atmosphere comes from photosynthesis (the process by which plants produce sugar from carbon dioxide and water), and the rest is mainly due to the electrolytic activity of water molecules by the current activity of the Earth's electric field.

Hello, plants absorb carbon dioxide and release oxygen.

Once upon a time, the earth had very small amounts of oxygen, and the surface of the earth was in very poor condition. The atmosphere is mainly N2 and CO2, and later, through complex changes, anaerobic organisms began to appear on the earth. Under the influence of life, the earth's oxygen began to accumulate continuously.

Later, algae appeared, and under the action of various organisms, oxygen began to accumulate. Plants quietly suppress photosynthesis, absorb carbon dioxide and release oxygen.

Oxygen, chemical formula amount: 32.00, colorless and odorless gas, the most common elemental form of oxygen. The melting point is minus 218.4 degrees Celsius, and the boiling point is minus 183 degrees Celsius.

Not easily soluble in water, about 30 ml of oxygen is dissolved in 1 liter of water. Oxygen in the air accounts for about 21 percent. Liquid oxygen is sky blue.

Stool Xun oxygen is a blue crystal. It is not very active at room temperature, and it is not easy to interact with many substances. However, it is very active at high temperatures and can be directly combined with a variety of elements, which is related to the electronegativity of oxygen atoms second only to fluorine.

Photosynthesis of plants

There are two main sources of oxygen on Earth. First, it originates from the photosynthesis of plants. It is the green leaves of plants that use chlorophyll to convert carbon dioxide absorbed in the air and water transported from the roots into organic matter such as starch and glucose when exposed to sunlight, and release oxygen.

Every year, the world's greenery absorbs large amounts of carbon dioxide from the air and produces a corresponding volume of oxygen. Second, the photolysis of water from the participation of non-living things, that is, the decomposition of water into oxygen by photo, which is an energy-consuming reaction.

In the early days of the Earth, when there were no signs of life, there was a small amount of oxygen, that is, stable ground-state oxygen molecules. But apparently this oxygen does not come from photosynthesis, so where does it come from? Relevant studies have shown that in the early atmosphere of the earth, there are more carbon dioxide and low-energy electrons, and these carbon dioxide molecules can trap low-energy electrons, and then two dissociation reactions may occur, producing carbon atom negative ions and free oxygen atoms or oxygen molecules, and in a specific energy range, the two dissociation reactions may produce oxygen molecules, and the free oxygen atoms as reaction products may also combine into oxygen molecules.

<> equation that denotes the outermost electron of an element's atom with a small black dot or " " around the element symbol is an electronic formula. The formula with **" " indicates that a pair of common electron pairs is a structural formula.

Oxygen is a non-polar element. The middle four electrons are shared to form a covalent double bond, which forms an 8-child stable structure with the other four electrons of its own. The oxygen atom has a total of 8 electrons, with the outermost six electrons; In order to achieve the 8-electron stable structure of the outer shell, it is necessary to form common electron pairs with other atoms.

Physical properties of oxygen.

Normally, oxygen coarse gas is a colorless and odorless gas that is slightly denser than air and is not easily soluble in water. Under certain conditions, Sun Min can be liquidated into a light blue liquid or solidified into a light blue solid. The fact that fish and shrimp in rivers and seawater can survive indicates that there is oxygen dissolved in the water in nature.

The above content reference: Encyclopedia - Oxygen.