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Factors Affecting the Rate of Evaporation

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What is Evaporation?

Evaporation is the natural process where the molecules of a liquid absorb the residual heat present in the liquid and escape in the form of vapour. There is no need to provide external heat to continue this process. It means that evaporation takes place at any temperature. It is a surface phenomenon. Here is the list of the factors affecting the rate of evaporation you should ponder upon. This part of the chapter is very crucial as the questions are quite conceptual. To answer the questions, find out how the factors change to affect the rate of evaporation.


Temperature

The prime factor that determines the rate of evaporation from the surface of a liquid is its temperature. We all know that temperature determines the amount of heat present in a liquid. The heat determines the kinetic energy of the molecules of the liquid. This energy is used to get rid of the intermolecular forces that bind the molecules together. When temperature increases, the heat increases resulting in higher kinetic energy of the molecules. It means that the molecules from the surface will get more energy to break the shackles of intermolecular forces and become vapour. This is the most important among the factors affecting evaporation.


Surface Area

If you concentrate on this factor, you can easily understand that the bigger the surface area, the higher will be the rate of absorption. When the surface molecules get more exposure, they will try to break the intermolecular forces even more. Consider this simple example. A cloth when folded takes more time to dry. If the area of the cloth is spread on the wire, it will dry quicker than in the previous case. This is also the same for evaporation on the liquid surface. When the area of the container is bigger, the rate of evaporation is also higher. This is how the experts simply explain the factors affecting evaporation.


Humidity

Humidity is the amount of water vapour contained in the surrounding atmosphere. The amount of water vapour that air can hold depends on the temperature of the surrounding area. It means that hot air has the capability of carrying more water vapour than colder air. Hence, the amount of moisture contained in air will determine how much more water vapour it can take at that temperature. The higher the humidity, the slower will be the rate of evaporation. If you consider a summer day, you will find that wet clothes dry up faster. On the other hand, clothes take more time to dry on a rainy day as the humidity on that day is higher.


Speed of Wind

If the day is airy, it will take less time for the clothes to dry. The reason is very simple. The air carrying water vapour passes and dryer air comes in to carry more. It means that a windy day will escalate the rate of evaporation. If there is no wind, the rate will be lower. This is how these examples explain factors affecting evaporation properly on this concept page.


Factors affecting the rate of evaporation

When a liquid particle gets in kinetic energy to break its liquid bonds and skate as a gas then the process of evaporation takes place. As each particle that evaporates takes away some energy from the rest of the pack that leads to cooling the remaining liquid particles. So let's find out the factors that affect evaporation:

  • Firstly, a faster rate of evaporation is the result of higher temperatures. Particles move fast at high temperatures so it is more likely for them to have enough energy to break their liquid bonds.

  • Secondly, the rate of evaporation increases with the movement of air (breeze) over the liquid. A dense vapour layer over the liquid is formed by the particles that evaporate. To form the liquid Bond many of these 'escapees' collide with the liquid.

  • The third factor is the dryness of the surrounding air that increases the rate of evaporation. There are a lot of water vapour particles in the surrounding area during a humid day. Therefore the rate of evaporation increases with the increasing dryness of the surrounding.


If you bundle up your washing in a heap to dry will it dry faster?

Wet clothes dry much faster if they are spread properly so that more surface area is exposed to the air. This is because liquid molecules can escape into the surrounding area more easily and at a faster rate.


Why Prefer Using the Concept Pages of Vedantu?

The experts at Vedantu are highly experienced in teaching such concepts to students. They know the exact way to make students understand new concepts by using easy examples. On this concept page, you will find a list of factors affecting evaporation with examples perfectly explained by the experts so that students can easily learn them and score well in the exams. It will also help you revise this part of the chapter very easily before an exam and save a lot of your time.

FAQs on Factors Affecting the Rate of Evaporation

1. How evaporation differs from vaporization?

When you state the various factors which affect evaporation after studying this concept page, you will find that vaporization is not a surface phenomenon. It only takes place when a liquid reaches its boiling point. Evaporation occurs on the surface and takes place at any temperature.

2. Write two factors which will increase the rate of evaporation.

The higher temperature of a liquid and lower humidity of the surrounding will increase the rate of evaporation on the surface of that liquid.

3. How does evaporation depend on wind speed?

When the wind speed is higher, the rate of evaporation is also high and vice versa. The wind carrying the vapour of the liquid will be replaced by empty wind quicker.

4. At what temperature does water evaporate?

The bonds holding the water molecules together are broken by energy, that is why water easily evaporates at the boiling point of 212°F,100°C, but the evaporation rate is much slower in the freezing point. Evaporation of liquid occurs when the rate of evaporation exceeds the rate of condensation. When these two process rates are equal then a state of ratio exists at the point of which the relative humidity is 100%.

5. How do people make use of evaporation?

Seawater contains minerals that can easily be obtained by the process of evaporation. A traditional technique used by people for thousands of years for the production of table salt is to evaporate the saline water by evaporation ponds. Water is an ideal source for the location of evaporation ponds for the process of extraction of not only table salt but also potassium, magnesium and bromine.

6. Difference between evaporation and boiling?

During the process of evaporation, liquid changes into a gaseous form at a temperature below the boiling point. Evaporation is also a surface phenomenon and takes place at any temperature, whereas liquid changes into gaseous form at the boiling point and boiling is also a bulk phenomenon and then takes place at a particular temperature. Boiling is a fast process as compared to evaporation.

7. Is evaporation a chemical process?

The process of evaporation is a physical change. The form of a liquid changes into gas, but it still remains water instead of being converted into any other substance, but in case of chemical change, a substance experiences change not in the physical form but also in its basic identity. During the process of evaporation, the water does not change into any other substance, and therefore all changes of state are physical changes.

8. Where can I find the concept page of my syllabus topics?

Vedantu provides a vast number of detailed information on the topics related to your syllabus.  The explanations provided on its official website are given by experts and will help you to develop understanding. The frequently asked questions at the end of the articles will also provide you with additional information or will help you clear your doubts if you have any.