What the air is like What the air is like

Answer When the primitive earth began to form, the lighter weight of the gas was in the outermost ring, which was the original air. The air is smelly and poisonous, and humans cannot survive in such air. Later, as the earth slowly shrank and cooled, the earth's crust solidified, and the composition of the air changed greatly, but there was still not much oxygen.

It wasn't until 100 million years ago that plants began to appear on land, absorbing carbon dioxide from the atmosphere and releasing oxygen, creating an environment for human survival.

Air, the gases that make up the atmosphere around the Earth. Colorless, odorless, the main components are nitrogen and oxygen, as well as a very small amount of radon, helium, neon, argon, krypton, xenon and other rare gases and water vapor, carbon dioxide and dust. Air at room temperature is a colorless and odorless gas, while liquid air is a light yellow liquid that flows easily.

Generally, when the air is liquefied, the carbon dioxide has been removed, so the composition of the liquid air is oxygen, nitrogen and argon, and the content of other components is very small, which can be omitted.

The most important components of the air are nitrogen and oxygen permeation. If calculated according to the volume fraction, the nitrogen gas is about 78%, and the oxygen bush teasing gas is about 21%. The other 1% air composition includes rare gases such as helium, neon, argon, krypton, xenon, and radon, with a volume fraction of about carbon dioxide, water vapor, impurities and other substances.

Physical properties of oxygen: colorless, odorless, gaseous. Chemical properties: relatively active, except for rare gases, small reactive metal elements (such as gold, platinum, silver), most of the elements can oxidize with oxygen.

Uses: supply respiration, support combustion, reaction heat release (such as heating, thermal power generation), pure oxygen can be used for electric welding, etc. Everyone knows that people can't do it if they don't have oxygen, and it can't do it if they inhale too much oxygen, which will lead to oxygen poisoning.

Composition analysis: 1. The chemical formula of nitrogen is N2, which is usually a colorless and odorless gas, and nitrogen is generally less dense than air. Nitrogen is one of the main components of air.

At standard atmospheric pressure, nitrogen becomes a colorless liquid when cooled to a point and a snow-like solid when cooled.

2. Carbon dioxide (carbon dioxide), chemical formula CO2. It is one of the main components in the air, is a common greenhouse gas, a gaseous compound, carbon and oxygen react to produce its chemical formula CO2, a carbon dioxide molecule is composed of two oxygen atoms and a carbon atom through covalent bonds.

1.The earth's atmosphere is mainly composed of 78% nitrogen, 21% oxygen, noble gases, carbon dioxide, other gases and water vapor, impurities*, and impurity gases*, with a density of .

Noble gases: helium HE, neon Ne, argon AR, krypton KR, xenon XE, radon RN, and the recently discovered UUO7 elements.

Impurity gases: carbon dioxide, sulfur dioxide, nitrogen dioxide, ozone, etc.

2.Mental manifestations or characteristics perceived by a person in a given environment.

Air is not a specialty of the Earth, and it is distributed on all planets. However, when the solar system was formed, the oxygen on the other planets was blown away by the solar wind, leaving only a few types of air, and the air on Earth was not blown away due to the protection of ozone.

Air refers to the mixture of gases in the Earth's atmosphere. It is mainly composed of 78% nitrogen, 21% oxygen, and also rare gases, other gaseous impurities and carbon dioxide. The composition of the air is not fixed, and the composition of the air changes as the altitude changes, the air pressure changes.

But for a long time, people thought that air was a single substance, until later the French scientist Lavoisier first came to the conclusion that air is composed of oxygen and nitrogen. At the end of the 19th century, scientists discovered through a large number of experiments that there were still rare gases such as helium, argon, and xenon in the air.

Air is a mixture of many gases. Its constant components are oxygen, nitrogen, and rare gases such as argon, neon, helium, krypton, and xenon, while the variable components are carbon dioxide and water vapor, and their content in the air varies slightly within a small range depending on the location and temperature on the earth. As for the indefinite components of the air, it varies from region to region, for example, sulfur dioxide is contained near metallurgical plants, chlorine is found near chlor-alkali plants, and so on.

In addition, there are trace amounts of hydrogen, ozone, nitrous oxide, methane and, to a lesser extent, dust in the air.

Experiments have shown that the percentage of constant components in the air is almost constant up to 100 km above the ground. In terms of volume content, oxygen accounts for about about it, nitrogen about about it, argon about about it, and generally speaking, the composition of air is relatively fixed. This is very important for the survival of humans and other animals and plants.

However, with the development of modern industry, the harmful gases and soot emitted into the air have changed the composition of the air and caused air pollution. Polluted air can seriously damage human health, affect the growth of crops, and cause damage to natural resources and buildings.

Harmful substances emitted into the air can be broadly divided into two categories: dust and gas. Worldwide, sulfur dioxide, carbon monoxide, nitrogen dioxide, etc., are the most gaseous pollutants emitted into the air. These gases mainly come from the combustion of fossil fuels (coal and oil) and the exhaust gases of factories.

Air refers to the mixture of gases in the earth's atmosphere, so air is a mixture, mainly composed of nitrogen, oxygen, noble gases (helium, neon, argon, krypton, xenon, radon), carbon dioxide and other substances (such as water vapor, impurities, etc.).

Oxygen in the air is necessary for all aerobic organisms. All animals need to breathe oxygen, as do the respiration of green plants. In addition, green plants use carbon dioxide from the air for photosynthesis, and air is almost the only carbon dioxide required by all plants**.