As is known, substances, and absolutely any can be in any condition:, solid, liquid, in phase or even in several states. This is primarily affected by the external pressure and temperature factor. These substances include water and water vapor, which are interesting to observe. If a substance transition occurs from one state to another, this process is called the transition from one phase to another or phase transition, which monitors the diagram. The concept of phase transformation relates to an identical concept and means the same. The substances in different phases of the aggregate state have different properties, this is especially true of the density of the substance. They differ due to molecular interaction.
Phase modifications
The modification of the solid state to the state of the liquid is the name of the melting. The change of liquid phase on the gaseous is evaporation. If the substance from solid goes into gaseous - this process is called sublimation. If we talk about reverse processes, you should be aware of such processes as: solidification, crystallization, and de - sublimation.
Water or in a different hydrogen oxide is called the H2O chemical formula. This is a molecule consisting of three atoms, two hydrogen and one oxygen. They are connected by a covalent bond. Water in its normal representation is a liquid that is absolutely transparent, does not smell and has no taste properties. As the diagram shows, in the gaseous state, water goes to the water vapor phase. It covers more than 70% of our planet and is represented in lakes, rivers, seas, oceans, etc. It is divided into freshwater and salty, and the second option is not suitable for drinking. Its role is so important that life without water simply cannot exist, weather conditions and climatic belts of the planet depend on it.
Water steam, like a gaseous condition of water, also does not have color, nothing smells and tasteless. Water pairs are in the troposphere and are formed at. Entering the air masses of water vapor, creates a certain pressure called partial. The gas pressure is measured by Pascals and is capable of moving to the next phase crystallization or ice formation. Gaseous condition of water is found in the natural environment. In its number of pairs, it may vary in the air, the maximum content reaches 4%. Water steam is not visible, but it can be represented as condensation in the form of fog, breathing, when you go to the cold or when water boils in a saucepan. Water steam in equilibrium defines an important characteristic of humidity.
The process of vaporization is and is the process of obtaining steam, and it is formed by boiling and evaporation. When evaporation occurs, the steam appears on the surface layer, the boiling causes the formation of a bubble surface that is broken from the bottom up. Boil occurs at a certain temperature and at its peak remains unchanged. With this process, a saturated pair is allocated, which is dry and wet. Dry does not contain water droplets, and the wet contains. Without a water pair, the water cycle does not occur in nature. Water steam in everyday life is found, for example, when you iron or are in a bath. It is precisely because pairs are blunting and has no color and smell, he found an application in human livelihoods. Even in solving global issues, the couples found its application, and a bright example of this was such a technique as a steam locomotive.
Using water vapor
Today, steam is also used, he found its application in the economic and production sector of activity:
- in treatment, such as inhalers;
- for fire extinguishing;
- steam boiler, steamer, autoclave, reactors and more;
- steam cars;
- Agriculture;
- Industry and woodworking production.
Thermodynamic properties
Water and water vapor are bodies actively working, for example, in a steam turbine. Properties are completely dependent on the design and other elements of the turbine. From the point of view of the properties of water, it is almost not compressed and if it is changed, it will not change the specific volume and will be equal to 10-3 m3 / kg. When heated, the enthalpy begins to change proportionally. Heating in the open vessel causes surface steam climbing up. Water molecules tear their connections, and heat is consumed, evaporation occurs. Wet pairs are represented in the form of a dry pair and a steam water saturated with bubbles. More recently, overheated couples were used for the steam turbine, which expanded in the turbine and became wet. The laws of mixing determine the thermodynamic properties of steam.
Diagram of water vapor
To track the process clearly, a water vapor diagram is invented, which has become an excellent substitute for numerous tables and can determine the values \u200b\u200bin equilibrium. The diagram is drawn up on the table and cannot be more accurate, because the table indicators are identical, simply transferred in the form of a certain schedule. Analyze the turbines is best in T, s diagram, where the axis of the abscissa is determined by entropy, and the ordinate absolute temperature. The horizontal lines on the diagram are denoted by isotherms, the vertical lines are called isoentrops. Calculate the analysis and operation of the turbine is best suited by H, S -Diagram. The fact that in the diagram is highlighted in a fat line indicates dry steam.
Liquid gas
Causes a large increase in temperature, which is constantly increasing when heated until it reaches the maximum point. A huge amount of heat is highlighted so that this process occurred. If the gas begins to cool, its temperature gradually decreases and at a peak point through the heat of the vaporization of the gas returns to the liquid state. Couples can turn into water only with heat loss. For example, steam is formed in the kitchen on the kitchen on the glass, and the windows are fisted, as soon as the room starts to lose the temperature, steam is lost in equilibrium and the droplets accumulate on the windowsill.
Even the human body is more than 60% consists of water, it is involved in biochemical reactions. Water removes harmful substances and poisons from the body, regulates the temperature of the human body. Water refers to the main source of energy resources, is used in HPP and turns the mechanical energy of water into electricity. Scientists of almost all countries were engaged in the study of water, and laboratory work was experimed. Steam - liquid in equilibrium is such a state when two substances are in phase gas, and evaporation is equal to the rate of condensate formation. In short, this is a system of transformation of par-water. The theory of equilibrium is achieved even in a relatively closed state when the water and vapor contact occurs without intervention. In 2011, a gigantic cloud of a couple was opened, and scientists of Harvard-Smithsonian Center made a report on the description of the phenomenon. Uniquely water is in other galaxies, since its main components are hydrogen and oxygen.
Water is the most amazing substance on Earth. It is her who we are obliged to life, as it participates in all the processes of vital activity. Water has the most unusual properties, and not all of them scientists managed to explain. For example, it turned out that it possesses memory and can respond to different words. And the most famous property of water is that it is the only substance that can be in all three aggregate states. Liquid is, actually, water, solid is ice. Gaseous condition of water, we can observe constantly in the form of steam, fog or clouds. An ordinary person does not think about that this is all the water, he is used to calling this word only liquid. Many do not even know how the gaseous state of water is called. But it is this particular feature that provides life on Earth.
Water value
This amazing moisture occupies about 70% of the earth's surface. In addition, it can be found at a great depth - in the thickness of the earth's crust and high in the atmosphere. The whole mass of water in the form of liquid, ice and the pair is called the hydrosphere. It is vital for all forms of life on earth. It is under the influence of water that climate and weather are formed around the world. And the existence of life depends on its ability to move from one aggregate state to another. This feature provides a water cycle in nature. Of particular importance is water in a gaseous state. Its property helps to transfer large moisture masses for huge distances. Scientists calculated that the sun evaporates a billion tons of water from the surface of the earth, which is transferred to another place, and then shed rain.
Gaseous condition of water
The peculiarity of water is that its molecules are capable of changing the temperature to change the nature of communication with each other. The main properties of it do not change. If you heat the water, its molecules begin to move faster. Those that come into contact with air tear their connections and mixed with its molecules. The water in a gaseous condition retains all its qualities, but also acquires the properties of the gas. Its particles are at a great distance from each other and intensively move. Most often, this condition is called water vapor. This is a colorless transparent gas, which under certain conditions will turn into water again. It is widespread on earth, but it is not visible most often. Examples of water in a gaseous state - fog or formed by boiling liquid. In addition, it is everywhere in air. Scientists have noticed that when it moisturizes it becomes easier.
What happens a couple?
Most often, water goes into a gaseous state when the temperature changes. An ordinary couple, which is all familiar, is formed when boiling. It is this whitish hot cloud we call water vapor. When the fluid during heating reaches and under normal pressure, this occurs at 100 °, the molecule is starting to evaporate intensively. Finding on colder items, they are condensed in the form of water droplets. If a large amount of fluid is heated, saturated steam is formed in the air. This state is when gas and water coexist, because the speed is the same. In the event that there is a lot of water vapor in the air, they say about its high humidity. When the temperature decreases, such air is intensively condenses moisture in the form of dew or fog droplets. But for the formation of fog, there are few specific conditions of temperature and humidity. It is necessary that in the air there is a certain amount of dust, around which moisture condenses. Therefore, in the cities of fogs because of dust are formed more often.
Water transition from one state to another
The process of formation of the pair is called vaporization. He is observed every woman when cooking. But there is a reverse process when gas turns back to water, settled on the items in the form of the smallest droplets. This is called condensation. What way the vaporization is most often happening? In natural conditions, this process is called evaporation. Water evaporates constantly under the influence of solar heat or wind. Artificially formation of steam can be caused by boiling water.
Evaporation
This is the process when the gaseous condition of water is obtained. It can be natural or accelerated with various devices. Water evaporates constantly. This property of her property has long been used for drying linen, dishes, wood or grain. Any wet object gradually dries due to the evaporation of moisture from its surface. Water molecules in their movement one by one are open and mixed with air molecules. By observing people, people understood how to speed up this process. For this, various devices and appliances were created.
How to speed up evaporation?
1. People noticed that the faster process takes place at high temperatures. For example, in the summer, the wet road dries instantly, which you can not say about the autumn. Therefore, the subjects are dried in warmer places, and recently special heated dryers have been created. And in frosty weather, evaporation is also happening, but very slowly. This property is used for drying valuable.
ancient books and manuscripts, placing them in special freezers.
2. Evaporation occurs faster if the area of \u200b\u200bcontact with air is large, for example, water will disappear faster than from the car. This property is used when drying vegetables and fruits, cutting them with thin slices.
3. More people noticed that the items dried faster under the influence of wind. This happens because water molecules are carried out by air flow, and they do not have the ability to condense again on this subject. This feature was used when creating a hair dryer and air dryers.
Water properties in gaseous condition
Water steam in most cases are invisible. But at high temperatures, when water evaporates at once, it can be noticed as a white cloud. The same thing happens in cold air, when the water molecules are condensed in the form of the smallest droplets that we also notice.
Water in a gaseous state can be dissolved in the air. Then they say that its humidity has risen. There is an extremely possible concentration of water vapor, which is called the "dew point". Above this limit occurs condensation in the form of fog, clouds or dew droplets.
Water molecules in a gaseous condition move very quickly, occupying a large volume. This is especially noticeable at high temperatures. Therefore, it is possible to observe how when boiling the kettle jumps the lid. The same property leads to the fact that the cracking is heard cracking. This evaporating water breaks wood fibers.
Water steam has elasticity. It is able to shrink and expand when the temperature changes.
Application of water vapor properties
All these properties have long been studied by people and are used for household and industrial needs.
- For the first time, the gaseous state of water was applied in many years. It was the only way to bring traffic and machines in the industry. Steam turbines are used now, and in vehicles, the gasoline engine has long supplanted steam. And now the locomotive can be seen only in museums.
- Everywhere and has long been applied in cooking. Cooking meat or fish for a couple makes them gentle and useful for everyone.
- Hot steam is also used for heating houses and industrial processes. Very effectively and quickly gained popularity among the population.
- Gaseous condition of water is now used in fire extinguishers of special design, which are used to extinguish petroleum products and other combustible liquids. Heated couple overlaps the air access to the heart rate, stopping burning.
- In recent years, the gaseous state of water for clothing care began to use. Special swaps will not only smooth out delicate things, but also will bring some spots.
- It is very effective to use water vapor to sterilize objects and medical instruments.
When is water vapor harmful?
There are on earth and places where water in a gaseous state is almost always. These are the valleys of geysers and the surroundings of acting volcanoes. It is impossible to be a person in such an atmosphere. It is hard to breathe hard, and high humidity prevents the evaporation of moisture from the skin, which can lead to overheating. You can also greatly burn the steam, which is formed when boiling water. And fogs can reduce visibility, leading to accidents. But in all other cases, the property of water to move into a gaseous state is used by a person for a good.
In this material we will look at Water parwhich is a gaseous state of water.
The gaseous condition refers to the three main aggregate states of water found in nature in vivo. This question is discussed in detail in the material. Aggregate water states.
Water par
Clean water par Nor neither color or taste. The greatest cluster of the steam is observed in the troposphere.
Water steam - water contained in an atmosphere in a gaseous state. The amount of water vapor in the air changes greatly; Its most of its maintenance - up to 4%. Water steam invisible; What is called the ferry in everyday life (couples from breathing in cold air, steam from boiling water, etc.), is the result of the condensation of water vapor, as well as fog. The amount of water vapor determines the characteristic essential for the state of the atmosphere - air humidity.
Geography. Modern illustrated encyclopedia. - M.: Rosman. Edited by prof. A. P. Gorkina. 2006.
How to produce water vapor
Water par It is formed as a result of "vaporization". Variousness occurs as a result of two processes - evaporation or boiling. When evaporation of pairs is formed only on the surface of the substance, when the pair is boiling, it is formed throughout the volume of fluid, as evidenced by bubbles, actively rising up during the boiling process. Boiling water occurs at temperatures that depend on the chemical composition of aqueous solution and atmospheric pressure, the boiling point remains unchanged throughout the entire process. ParForming as a result of boiling is called saturated. Saturated par In turn, it is divided into a saturated dry and rich wet steam. Saturated wet steam consists of suspended water droplets, the temperature of which is at the boiling level, and, accordingly, the pair itself, and the saturated dry par Does not contain water droplets.
There is also a "superheated pairs", which is formed with the further heating of the wet pair, this type of steam has a higher temperature and lower density.
Water steam is an indispensable element of such an important process for our planet as a cycle of water in nature.
With the ferry we are constantly confronted in daily life, it appears - above the spout of the kettle when boiling water, when ironing, when visiting a bath ... However, do not forget that, as we have noted above, clean water par Nor neither color or taste. Thanks to its physical properties and qualities, couples have already found its practical application in the economic activity of a person. And not only in everyday life, but also in solving large global tasks. For a long time, steam was the main driving force of progress both in direct and in the figurative sense of this expression. It was used as a working fluid of steam machines, the most famous of which is the locomotive.
Using a couple of man
Couples and in our time is widely used in economic and production needs:
- for hygiene purposes;
- for medicinal purposes;
- to extinguish fires;
- thermal properties of steam are used (steam as heat carrier) - steam boilers; steam shirts (autoclaves and reactors); warming up "fatal" materials; heat exchangers; heating systems; Rod concrete products; in a special kind of heat exchangers ...;
- use the transformation of the energy of steam in motion - steam machines ...;
- sterilization and disinfection - Food industry, agriculture, medicine ...
- steam as a humidifier - in the production of reinforced concrete products; plywood; in the food industry; in the chemical and perfume industry; in woodworking industries; in agricultural production ...;
Summing up, we note that, despite all its "inconsistency", water vapor is not only an important element of the global ECO system of the Earth, but also a very useful substance for the economic and economic activity of a person.
Page 1
Water steam continuously enters the atmosphere by evaporation from water surfaces, with wet soil and by plant transpiration, while in different places and at different times it enters various quantities. It extends to the earth's surface, and the air flows are transferred from the same places of the Earth to others.
The atmosphere may occur saturation. In such a state of water steam, it is contained in air in an amount maximum possible at a given temperature. The water steam is called saturating (or saturated), and the air containing it, saturated. The saturation condition is usually achieved with a decrease in air temperature. When this state is achieved, then with a further decrease in temperature, part of the water vapor becomes excessive and condensed, goes into a liquid or solid state. In the air there are water droplets and ice crystals of clouds and fogs. Clouds can evaporate again; In other cases, the droplets and crystalline clouds, cultivating, can fall onto the earth's surface in the form of precipitation. As a result, the content of water vapor in each site of the atmosphere is continuously changing.
With water steam in the air and with its transitions from a gaseous state in liquid and solid, the most important processes of weather and climate features are associated. The presence of water vapor in the atmosphere significantly affects the thermal conditions of the atmosphere and the earth's surface. Water steam strongly absorbs the long-wave infrared radiation, which the earth's surface radiates. In turn, he himself radiates infrared radiation, most of which goes to the earth's surface. This reduces the night cooling of the earth's surface and thereby also lower air layers. In the evaporation of water from the earth's surface, large amounts of heat spend, and when the water vapor condensation in the atmosphere, it is warmly given to air. The clouds arising from condensation reflect and absorb solar radiation on its path to the earth's surface. The precipitates falling out of the clouds are an essential element of weather and climate. Finally, the presence of water vapor in the atmosphere is important for physiological processes.
The moisture content of the air, first of all, depends on how much water vapor enters the atmosphere by evaporation from the earth's surface in the same area. Naturally, it is more than above the oceans, since evaporation from the surface of the ocean is not limited to water reserves. At the same time, in every place, the moisture content depends on the atmospheric circulation: air flows bring the air masses more wet or more dry from other areas of land into this area. Finally, for each temperature there is a saturation state, i.e. there is some extreme moisture content that cannot be exceeded. For different purposes, three more characteristics of humidity are used. First, this is the dew point τ, i.e., the temperature at which water pair contained in the air could saturate air. For example, if at air temperature + 27 °, steam elasticity in it is 23.4 MB, then such air is not saturated. In order for it to become saturated, it would be necessary to lower its temperature to + 20 °. This is the last value of + 20 ° and is in this case the dew point for air. Obviously, the smaller the difference between the actual temperature and the dew point, the closer the air to saturation. When saturation, the dew point is equal to the actual temperature.
Another characteristic is called the mixture ratio. The ratio of the mixture is the content of water vapor in grams per kilogram of dry air. This value differs little from the specific humidity.
The third characteristic is a lack of humidity, i.e. the difference between the elasticity of saturation E at a given air temperature and the actual elasticity E vapor in the air: d \u003d e - e. In other words, the moisture deficiency characterizes how much water vapor is lacking for air saturation at this temperature . It is expressed in millimeters of a mercury pillar or in millibar.
For the nature of the water of water vapor, it is of great importance. It is present in the atmosphere, used in the technique, serves as an integral part of the process of origin and life development on Earth.
In the textbooks of physics, it is said that a water vapor - this can observe him, putting a kettle on fire. After some time, a jet of steam begins to escape from his nose. The case is due to the fact that water can be in different, as determined by physics, aggregate states - gaseous, solid, liquid. Such properties of water and explain its comprehensive presence on Earth. On the surface - in a liquid and solid state, in the atmosphere - in gaseous.
This property of water and the sequential transition of it in different states create in nature. The liquid evaporates from the surface, rises into the atmosphere, is transferred to another place in the form of a water vapor and is dropped in the form of rain, providing the necessary moisture new places.
In fact, it works a peculiar steam machine, the source of energy for which is the sun. With the considered water vapor processes, it additionally heats the planet due to the reflection of the heat radiation of the Earth back to the surface, causing a greenhouse effect. If it were not for such a peculiar "pillow", the temperature on the surface of the planet would be 20 ° C below.
As a confirmation of the above, you can recall the sunny days in winter and summer. The warm season is high, and the atmosphere, as in a greenhouse, heats the land, in the winter in sunny weather there are sometimes the most significant cold.
Like all gases, water vapor has certain properties. One of the parameters that determine this will be the density of water vapor. By definition, this is the amount of water vapor contained in one cubic meter of air. In fact, it is determined by the latter.
The amount in the air of water is constantly changing. It depends on temperature, pressure, terrain. The moisture content in the atmosphere is an extremely important parameter for life, and for it is constantly observed, for which they are used by special devices - hygrometer and psychrometer.
The change in humidity is caused by the fact that the water content in the surrounding space changes due to the processes of evaporation and condensation. Condensation is a phenomenon, inverse evaporation, in this case steam begins to turn into a liquid, and it falls on the surface.
At the same time, depending on the ambient temperature, fog, dew, frost, ice, ice may form.
When warm air, water, in contact with cold earth, Rosa is formed. In winter, at negative temperatures, Iave will be formed.
A little different effect occurs when cold comes, or begins to cool the air heated per day. In this case, fog is formed.
If the surface temperature on which pairs is condensed is negative, the ice occurs.
Thus, numerous natural phenomena, such as fog, dew, frost, ice, are obliged to their formation of a water pair contained in the atmosphere.
In this regard, it is worth mentioning the formation of clouds, which, too, directly participate in the formation of the weather. Water, evaporating from the surface and turning into water vapor, rises up. When the height is reached, where condensation begins, it turns into a liquid, and the formation of clouds. They can be several types, but in the light of the question under consideration it is important that they are involved in the creation of a greenhouse effect and transfer of moisture into new places.
In the stated material, it was shown that he represents water vapor, its influence on the vital processes occurring on Earth.
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