We explain that what are examples of Evaporation? The evaporation is a physical phenomenon that occurs in liquids, and is that the particles are transformed into steam . This is achieved by adding energy to them in the form of heat or by taking pressure off them, such as by subjecting them to a vacuum, for example. To better understand this change of state, it is necessary to describe the two states of matter involved:
In the liquid state , the particles are arranged one on top of the other, in layers, and have moderate cohesion forces , much lower than those of the solid state. This makes them cover the volume of the container that contains them and take their shape. They have a kinetic energy that will depend in part on the movement of the container. They can be almost at rest.
In the vapor state , which is close to gaseous, the particles are dispersed, colliding with each other and traveling towards the lower pressure areas within the container that contains them. They end up encompassing the entire container. Particles in the vapor state are characterized in that, in contact with a cold surface, they can be converted back to the liquid state .
Examples of evaporation
1. A puddle of antifreeze on the pavement evaporates in the sun, especially if passing cars that stir up the liquid particles. If this happens, they are more likely to detach and receive the heat that will evaporate them.
2. A lagoon, exposed to the heat of the sun, evaporates . The liquid particles on its surface receive heat and transform into vapor. When these are already floating through the air, other deeper particles remain on the surface. This causes for the lagoon the risk of drying up and disappearing if the heat remains.
3. The liquid content of an aerosol is blown out like a breeze, wetting surfaces. If these surfaces are hot or the environment is very hot, the liquid particles will transform into steam. If they are sprayed very fine or small, the faster the evaporation will be.
4. The sweat generated by the body during outdoor exercise tends to evaporate, especially if there are hot air currents that carry heat to the most superficial drops. If the sportswear is wet with sweat, there will be a uniform surface on which the phenomenon will occur, at least until it is removed from the heat of the environment.
5. A drink in a glass evaporates, especially if it is exposed to the sun, such as on a table in the garden. It happens the same as in lagoons, but on a smaller scale: the particles on the surface heat up and evaporate, giving way to other deeper particles that will evaporate as well.
6. The ethyl alcohol contained in a medicine cabinet bottle evaporates. If the bottle is not kept tightly capped, the alcohol vapor will escape to the outside.
7. Milk , in industrial plants, is subjected to evaporation to remove water from its composition , in the form of steam. It is heated until it begins to boil and the vapors, which are largely made up of water, are drawn into a vacuum line to condense and separate. The milk that had been put to heat, finally, has a higher concentration of milk components.
8. Mercury , which is one of the densest metals and with such a great cohesion force among its particles, is in a liquid state at room temperature. If heated sufficiently, it evaporates . For this process, and for all contact with this metal, the human being must take special care, and do so with personal protective equipment, since its vapors generate affections in the central nervous system when breathed frequently.
9. Fruit juices are homogeneous liquid mixtures that, if allowed to evaporate, will leave a trace of the fruit pulp, which is made up of natural sugars and water, in part. After complete evaporation, the tiny fruit tissues will remain as residue.
10. Brine reserves , which is a liquid mixture of salts such as sodium sulfate (Na 2 SO 4 ), are subjected to constant evaporation in lagoons, so that the water that composes it is naturally evaporated by the action of the sunlight. In this way, you will have a more concentrated brine, and with the possibility of providing purer salt crystals and without much investment.
Factors influencing evaporation
Evaporation as a physical phenomenon is influenced by a number of factors:
- The density of the liquid
- The concentration of the liquid
- The pressure to which the liquid is subjected
- The temperature in the liquid and the ambient
The density of the liquid and the concentration are properties that act the same. If it is a pure liquid, its density is the result of the attractive forces between its particles, and it will evaporate to a degree that will depend on how close they are. If they are close together, little will evaporate. If its forces are weak, it can evaporate to a great extent.
If the liquid is a mixture, that is, a solution, its density will increase with the amount of solute it has . For example, a water with sugar is more dense than a natural water. This is the same as concentration . A water with sugar is more concentrated than a natural water. A water with sugar has its particles closer together, therefore it will evaporate little.
The pressure at which the liquid is is going to tell how much it will be able to evaporate. If the pressure is high, the liquid will have its particles compressed. Therefore, it will evaporate little. On the other hand, if the liquid is kept under vacuum or at low pressure, its particles will be free enough to evaporate a lot.
The temperatures of the liquid and environmental are the most important factors affecting evaporation. Since temperature is the measure of the average kinetic energy of the liquid, it is clear that the higher the temperature , the more dispersed the particles and evaporate more easily .
Evaporation in industry
Evaporation is a widely used physical phenomenon in industry, in the food and chemical fields, for example. Generally, the intention is to separate water from the work materials, to make them easier to handle and less expensive to reach the final product. Materials include dairy products, juices, or aqueous solutions of salts, acids, and alkalis.
Evaporation is achieved by means of stainless steel equipment called evaporators , which are large containers heated by an internal line of steam, supplied from a boiler at the plant. These hold the liquid and have pathways through which the separated vapor will escape.
If the process is simple, the evaporation can be carried out in a single step, in a simple effect evaporator ; if it is more complex and requires more steps, it can be done in double effect or in multiple effects , to separate as much water as possible, in the form of steam.
Sublimation as an evaporation
The sublimation can be treated as an evaporation that is a phenomenon that produces vapors. However, it starts from the solid state and changes directly to steam . It is therefore that it is not formally considered as evaporation, but as a separate process, with its particular characteristics.
A chemical element that has the ability to sublimate is iodine , a halogen that appears as violet crystals and whose vapors are constantly given off. If a fresh surface is placed just above, where the vapors collide, it is possible to see that the crystals are forming again, returning to the solid state.