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What is Evaporation?
Evaporation is a process wherein a liquid changes into its gaseous or vapour state.
This experiment aims to understand the evaporation process.
Here, we will find the rate of evaporation of spirit and water. Let us take a look at this experiment in a virtual lab.
Apparatus required
- Burner
- Tripod stand
- Wire gauze
- China dish
- Beaker containing water
- Stopwatch
Chemicals required
- Spirit
- Water
Procedure
Place the china dish containing about 20 mL of water over the heating setup. Heat the china dish slowly with the help of a burner. Observe how the contents in the china dish disappear with time. Continue heating until all the water evaporates. Take two china dishes containing C10 mL volume of water and spirit, respectively. Compare the speed of evaporation between spirit and water at room temperature.
The intermolecular forces of attraction between the water molecules are very strong compared to the spirit. So, spirit evaporates at room temperature, whereas water evaporates significantly only on heating.
So, we conclude that water evaporation occurs quickly on heating but spirit can not be heated directly to observe evaporation because spirit is a highly flammable substance. Spirit is more volatile compared to water at room temperature due to weaker intermolecular forces. Therefore, the relative rate of evaporation of spirit is higher than that of water at room temperature.
Precautions
To perform this experiment, we need to take a few precautions. Let us see what they are.
- The china dish and the burner must be properly handled in order to avoid injuries.
- Caution is taken to turn off the burner when not in use to prevent any shortcomings.
FAQs on Evaporation
What is evaporation?
Answer: Evaporation is when a liquid substance becomes gaseous without being heated to its boiling point.
What is the effect of temperature on evaporation?
Answer: Temperature has a significant effect on the process of evaporation. As a liquid’s temperature increases, the evaporation rate also increases. This relationship is explained by the kinetic theory of matter, which states that as the temperature rises, the kinetic energy of molecules within a substance increases.
Which of the following has a higher rate of evaporation?
Answer: Water evaporation occurs quickly on heating, but spirit can not be heated directly to observe evaporation because spirit is a highly flammable substance. Spirit is more volatile than water at room temperature due to weaker intermolecular forces. Therefore, the relative rate of evaporation of spirit is higher than that of water at room temperature.
How does surface area affect the rate of evaporation?
Answer: Surface area is directly proportional to the speed of evaporation. The larger the surface area of the liquid, the faster will be its rate of evaporation.
How does the addition of salt in water affect the rate of evaporation?
Answer: The introduction of salt into water occupies the spaces between water molecules on a molecular level. Consequently, the presence of salt hinders the rapid evaporation of water. As a result, the rate of water evaporation experiences a reduction.
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