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In general, when talking about States of the material reference is made to three large groups: solid, liquid and gaseous.
At gaseous state, the molecules are not cohesive, so they do not produce a consistent body, with a defined shape and volume, as solids do. For this reason, gases are often imperceptible to vision, although they are usually perceptible to smell.
The gases spread throughout the available space.
State changes:
- The passage of the state solid to gaseous is called sublimation;
- The passage of the state liquid to gaseous is known as vaporization;
- The passage from the gaseous state to the liquid is called condensation.
See also: Solid Examples
Characteristic of gases
It is stated that in the gaseous state, the molecules arein permanent motion, the particles colliding with each other and with the walls of the container that contains them.
- These particles move at different speeds according to the atmospheric temperature.
- Movement is faster in warmer environments: this phenomenon is the cause of increases in the atmospheric pressure.
- The gravitational and attractive forces they are insignificant compared to the tendency of the particles that make up gases to move.
Research on gases and air:
Different studies and theoretical contributions have been carried out in the framework of physics and chemistry to analyze the characteristics and behavior of gases.
The most immediate motivation for these studies is that the air, that almost all living beings need to breathe, it must have a standard composition, with a sufficient amount of oxygen. The carbon dioxide it is also an important air gas, plants need it to carry out the process of photosynthesis.
Certain gases must not exceed a certain proportion in the air; in fact some gases from certain industries are extremely toxic and harmful to health, and they can pollute the atmosphere we breathe; the carbon monoxide is an example of them.
See also: Examples of Gas Mixtures
Gas properties
Among the main properties of gases, we find:
- Expansion and comprehensibility (gases can be compressed by the action of an external force).
- Thediffusion and effusion.
The behavior of the gases was described in detail through the so-called 'gas laws’Formulated by scientists such as Robert Boyle, Jacques Charles, and Gay-Lussac.These physicists related parameters such as volume, pressure and temperature of the gases, which meet in the call General gas law.
- Emissions coming out of the tailpipe of a moving car
- The gases used in refrigeration of refrigerators and air conditioners
- The clouds of the sky, composed of water vapor
- Carbon dioxide in soft drinks
- The tear gas, which produces an unpleasant sensation on the human body
- The gas balloons (filled with helium gas)
- The natural gas used as fuel in the home network
- Biogas
- The smoke generated by burning any solid
- Carbon monoxide
- Acetylene
- Hydrogen
- Methane
- Butane
- Ozone
- Oxygen
- Nitrogen
- Hydrogen sulfide gas
- Helium
- Argon
See also: Examples of Liquids
