Gas is one of the states of matter. It does not have a specific volume, filling with itself the entire container in which it is located. But it has fluidity and density. What are the lightest gases? What are they characterized by?
The lightest gases
The name “gas” was coined back in the 17th century due to the consonance with the word “chaos”. Particles of matter are indeed chaotic. They move in random order, changing the path every time they collide with each other. They try to fill all the available space.
Gas molecules are loosely coupled, unlike liquid and solid molecules. Most of its species can not be felt with the help of the senses. But gases have other characteristics, for example, temperature, pressure, density.
Their density increases with increasing pressure, and with increasing temperature they expand. The lightest gas is hydrogen, the heaviest is uranium hexafluoride. Gases are always mixed. If gravitational forces act, then the mixture becomes inhomogeneous. The lungs go up, the heavy ones, on the contrary, go down.
The lightest gases are:
- hydrogen;
- nitrogen;
- oxygen;
- methane;
- carbon dioxide.
The first three relate to the zero group of the periodic table, and we will talk about them below.
Hydrogen
Which gas is the lightest? The answer is obvious - hydrogen. This is the first element of the periodic table, which is 14.4 times lighter than air. It is denoted by the letter H, from the Latin name Hydrogenium (giving birth to water). Hydrogen is the most common element in the universe. It is part of most stars and interstellar matter.
Under normal conditions, hydrogen is absolutely harmless and non-toxic, has no smell, taste and color. Under certain conditions, it can significantly change properties. For example, mixing with oxygen, this gas easily explodes.
It can be dissolved in platinum, iron, titanium, nickel and ethanol. From exposure to high temperatures, it passes into a metallic state. Its molecule is diatomic and has a high speed, which provides excellent thermal conductivity of the gas (7 times higher than that of air).
On our planet, hydrogen is mainly found in compounds. In its importance and involvement in chemical processes, it is the second after oxygen. Hydrogen is contained in the atmosphere, is a part of water and organic substances in the cells of living organisms.
Oxygen
Oxygen is indicated by the letter O (Oxygenium). It also has no smell, taste and color under normal conditions, and is in a gaseous state. Its molecule is often called dioxide, as it contains two atoms. There is its allotropic form or modification - gas ozone (O3), consisting of three molecules. It has a blue color and has many characteristics.
Oxygen and hydrogen are the most common and lightest gases on Earth. There is more oxygen in the crust of our planet, it makes up about 47% of its mass. In a bound state, its water contains more than 80%.
Gas is an essential element in the life of plants, animals, humans, and many microorganisms. In the human body, it contributes to the implementation of redox reactions, falling into our lungs with air.
Due to the special properties of oxygen, it is widely used for medical purposes. With its help, hypoxia, gastrointestinal pathologies, asthma attacks are eliminated. In the food industry, it is used as packaging gas. In agriculture, oxygen is used to enrich water in fish farming.
Nitrogen
Like the two previous gases, nitrogen consists of two atoms, does not have pronounced taste, color and smell. The symbol for its designation is the Latin letter N. Together with phosphorus and arsenic, it belongs to the subgroup of picnogens. The gas is very inert, for which it received the name azote, which translates from French as "lifeless." The Latin name is Nitrogenium, that is, "giving birth to saltpeter."
Nitrogen is found in nucleic acids, chlorophyll, hemoglobin and proteins, is the main component of air. Many scientists explain its content in humus and the earth's crust by the eruption of volcanoes that carry it from the mantle of the Earth. In the Universe, gas exists on Neptune and Uranus, is part of the solar atmosphere, interstellar space and some nebulae.
Man uses nitrogen mainly in liquid form. It is used in cryotherapy, as a medium for packaging and storage of products. It is considered the most effective for extinguishing fires, displaces oxygen and robs the fire of “potpitka”. Together with silicon, it forms ceramics. Nitrogen is often used for the synthesis of various compounds, for example, dyes, ammonia, explosives.
Conclusion
Which gas is the lightest? Now you yourself know the answer. The lightest are hydrogen, nitrogen, and oxygen, which belong to the zero group of the periodic system. They are followed by methane (carbon + hydrogen) and carbon monoxide (carbon + oxygen).