Why Do Water Without Salt Evaporate Faster Than With Salt?

12 Answers

Anonymous Profile
Anonymous answered
When we add substances as sugar or salt in water, it causes the water to evaporate more slowly at a given temperature. Theory behind this is not difficult as when you add salt in water then salt molecules form a bond with water molecules. So the movement of molecules decreases and as we know when molecules move fast then water evaporates quickly. Because of the bond between water and salt molecules, It takes extra energy to break this bond and that's slows down the evaporation.

Another reason is that as every one knows water starts to evaporate at high temperature. At 100 degree centigrade water starts boiling and it also starts evaporating. But the cause for boiling of water is the speed of molecule. When heat is provided to water then molecules of water starts moving with great speed and soon their speed come to that point where that is considered enough for water to boil and evaporate.

When we add salt then salt then water becomes heavier and water's molecules make bond with salt's molecules and as a result it affects on thee speed of molecules. So even if we provide heat to water then molecules start moving very slowly and they take more time to evaporate than water without salt.
thanked the writer.
Caitlin commented
Wow! That really helped me. Thanks so much. I have this science report to do, and this just helped me with a whole lot. :)
Anonymous commented
Thanks i had a science fair project and i got an A thanks for the answer
amber Jhon Profile
amber Jhon answered
Water without salt evaporates faster as compare to water with salt. Basically, when a solution has higher boiling point as compare to the pure solvent then it is known as boiling elevation. As a result of the boiling point elevation, the solution of water and salt takes a longer time to adjust their vapor pressure and with the atmospheric pressure. This reduces the evaporation of salty water as compare to pure water. Moreover, this process takes place whenever a
non-volatile solute like salt, is mixed in a pure solvent like water.
Shalin Choksi Profile
Shalin Choksi answered
Water which contains salt is known as saline water and due to the salt content in the water,it makes the water much heavier therefore it needs more than a hundred degrees Celsius in order to evaporate which definitely takes more time than water without salt content which also means that the salt water has a lower saturated vapour pressure which makes the evaporation process quite slow and long.

The freezing process of saline water will also take a long time which means it will have to go way below zero degrees in order to get it properly solidified. In the end, when the water starts evaporating, it will leave behind the salt forms. This is also the reason why the lakes dry up much faster and the sea water takes a long time to evaporate.
Anonymous Profile
Anonymous answered
This is due to the intermolecular forces of atoms and molecules which repel or attract all elements. In the case of a soluble salt when dissolved into water it forms hydrogen bonds with the water through the dipole ends of the water molecule and the salt. These bonds make it necessary to apply more kinetic energy to create enough movement to break the bonds and the attraction between water molecules to change of state, in this case liquid to gas.
Intermolecular forces include : Van der Wals forces, Dipole forces (polar) and others.
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Luz Zamora Profile
Luz Zamora answered
Because salted water has more matter to evaporate than water without salt.
Anonymous Profile
Anonymous answered
Because salt water has more mass then normal water ,unless you put a small amount of salt
Anonymous Profile
Anonymous answered
When I tested my project the salt water seem to evaporate the fastest, following the plain water, then the sugar water. Does it depend on the salt you use?
Anonymous Profile
Anonymous answered
This is because its harder for the water to evaporate because the obstacles (the salt) are in its way!

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