We explain what steam is, its presence in the atmosphere, uses and what is vapor pressure. Also, differences between gas and steam.
What is steam?
When we talk about steam, we can refer to anymatter which is in a gaseous state, as a consequence of having modified its conditions of Pressure Ytemperature.
In this sense, it is a concept very similar to that of gas, but with the difference that gases tend to be so under ordinary conditions of pressure and temperature, while steam is always the result of heating an element that, temperature environment, it is usually solid or liquid.
Furthermore, when referring to steam, we generally speak ofwater steam, that is, the gas that liquid water becomes when we introduce enoughheat like to take her to herBoiling point (100 ° C or 212 ° F), that is, when the water boils or evaporates.
When it's in that condition, the Water it continues to be odorless and insipid, transparent, although under certain condensation conditions it appears as a whitish stain, more or less thick, known as mist, fog or clouds, depending on its appearance conditions.
Water vapor is extremely abundant in the atmosphere from our planet, something essential for the continuity of hydrological cycle, and to stabilize it climatically.
Its spontaneous production in the nature It is due to solar rays and geothermal heat. Furthermore, in numerous industries It has been produced and used since the 18th century, when it played an eminent role in the Industrial Revolution.
Water, being transformed into steam, increases its volume 1,700 times, which generates an increase in local pressure (vapor pressure) that can be converted into mechanical work, with the appropriate instruments. That is the principle behind the steam engine, the same one we use today to generate electricity In many parts of the world.
Gaseous state
Vapor exists in the gaseous state of matter, in which particles are dispersed and have a minimal force of mutual attraction, due to the high levels of Energy internal they possess.
Gases do not have a defined shape or their own volume, but they expand until they fill the container where they are, like all fluids. At the same time, gases are volatile, compressible and can become plasma, or in liquids or even solid, manipulating their temperature and the pressure at which they are.
Gas and steam
As said before, gas and steam are practically terms synonyms, since all vapor is gaseous. However, not all gas is a vapor, since the latter necessarily comes from subjecting a liquid or metallic element to a process of evaporation or vaporization, that is, to force it to change its physical state to gaseous.
Thus, for example, water vapor is a gas obtained by boiling water, while carbon dioxide It is the organic gas that we exhale when we breathe, and it is not a form of vapor, although it leaves our body together with abundant water vapor.
Uses of steam
Steam has enormous industrial and economic applications, such as:
- Generation of electricity. Steam is key in generatingelectric power, for which a steam turbine is used. The logic of this circuit is what allows power plants with different fuels (nuclear, coal or fuel) to operate. natural gas, for example), in which water is constantly heated to a boil and the steam, as it expands, mobilizes the turbines, generating the work necessary to produce electricity. About 90% of the world's electrical energy is obtained in this way.
- Domestic uses. Steam is used for cooking, cleaning fabrics and fabrics, and even heating buildings and homes. These different uses, in the kitchen or in the boilers of a building, in turn require a certain fuel.
- Sterilization. Given the high temperatures that steam can reach, it is used in sterilization procedures of soils, laboratory supplies and other materials that require a non-toxic germ cleaning mechanism and bacteria.
- Mechanical strength. As in the case of power plants, it is possible to take advantage of the force of steam to mobilize mechanical systems, based on their need to expand. The steam engines invented during the Industrial Revolution took advantage of this property, and used it as a source of movement, in trains, ships and even steam cars, prior to the discovery of the fossil fuels.
Vapor pressure
Vapor pressure is the force that vapor exerts on the liquid phase of the same material in a closed system at a given temperature.
Its value is independent of the amount of liquid and gas stored, but depends on the nature of the substance. According to him International System of Units It is expressed in pascals (Pa), equivalent to one newton per square meter (N.m2).