Why Does Salt Water Evaporate Faster Than Fresh Water?

[CINDY SMITH]

Why does salt water evaporate faster than fresh water? My science is a bit
sketchy. From what I understand (I'm an English major, forgive me), salt water
evaporates faster because the atomic charge of salt water is different from
that of fresh water. Salt, I think, also absorbs water? I've heard that
rubbing salt in an open wound causes the wound to heal faster because salt
absorbs blood, for example. Salt somehow changes the molecular balance of
water. Am I on the right track? Can someone recommend a book I can find in a
library that answers the question? Sorry if the question is too basic.

Thanks!

--
Cindy Smith
Spawn of a Jewish Carpenter
GO AGAINST THE FLOW! \\ _\\\_ _///_ //
>IXOYE=('> <`)= _<< A Real Live Catholic in Georgia
c...@dragon.com // /// \\\ \\

Delay not your conversion to the LORD,
Put it not off from day to day
Ecclesiasticus/Ben Sira 5:8

Read Catholic.Bible by pointing your news client to vega.vec.net
Read Catholic.Literature by pointing your news client to vega.vec.net

[Marvin3809]

>From: c...@vecnet.com (CINDY SMITH)
>Date: Thu, Apr 2, 1998 10:31 EST

>Why does salt water evaporate faster than fresh water? My science is a bit
>sketchy. From what I understand (I'm an English major, forgive me), salt
>water
>evaporates faster because the atomic charge of salt water is different from
>that of fresh water. Salt, I think, also absorbs water? I've heard that
>rubbing salt in an open wound causes the wound to heal faster because salt
>absorbs blood, for example. Salt somehow changes the molecular balance of
>water. Am I on the right track? Can someone recommend a book I can find in
>a
>library that answers the question? Sorry if the question is too basic.
>
>Thanks!
>
>--
>Cindy Smith

What is the basis for your saying that salt water evaporates faster than fresh
water? I doubt that it does.

Marvin Margoshes

[David Whitman]

On 2 Apr 98 11:31:10 EDT, c...@vecnet.com (CINDY SMITH) wrote:

>Why does salt water evaporate faster than fresh water? My science is a bit
>sketchy. From what I understand (I'm an English major, forgive me), salt water
>evaporates faster because the atomic charge of salt water is different from
>that of fresh water. Salt, I think, also absorbs water? I've heard that
>rubbing salt in an open wound causes the wound to heal faster because salt
>absorbs blood, for example. Salt somehow changes the molecular balance of
>water. Am I on the right track? Can someone recommend a book I can find in a
>library that answers the question? Sorry if the question is too basic.

I have no direct knowlege of the relative evaporation rates of
distilled vs. salt water. However, my expectation is exactly the
opposite of what you're proposing. Salt water will almost certainly
evaporate more SLOWLY than pure water, because the non-volatile salt
cuts the activity of the water.

Image the surface of the water, where H2O molecules are escaping into
the gas phase. In salt water, some of that surface area is taken up
by sodium and chlorine ions that won't evaporate, and get in the way
of water leaving.

--
Dave Whitman "Opinions expressed are those of the author, not Rohm and Haas Co."
dwhi...@rohmhaas.badaddr.com
Remove -->".badaddr" or replies will bounce.

[Ariens, M.D. GST]

CINDY SMITH wrote:
>
> Why does salt water evaporate faster than fresh water? My science is a bit
> sketchy. From what I understand (I'm an English major, forgive me), salt water
> evaporates faster because the atomic charge of salt water is different from
> that of fresh water. Salt, I think, also absorbs water? I've heard that
> rubbing salt in an open wound causes the wound to heal faster because salt
> absorbs blood, for example. Salt somehow changes the molecular balance of
> water. Am I on the right track? Can someone recommend a book I can find in a
> library that answers the question? Sorry if the question is too basic.
>

> Thanks!
>
> --
> Cindy Smith
> Spawn of a Jewish Carpenter
> GO AGAINST THE FLOW! \\ _\\\_ _///_ //
> >IXOYE=('> <`)= _<< A Real Live Catholic in Georgia
> c...@dragon.com // /// \\\ \\
>
> Delay not your conversion to the LORD,
> Put it not off from day to day
> Ecclesiasticus/Ben Sira 5:8

The Lord seems O.K. to me, but its ground staff...?

>
> Read Catholic.Bible by pointing your news client to vega.vec.net
> Read Catholic.Literature by pointing your news client to vega.vec.net

Who said that salt water evaporates more quickly? Never heard of.

Mark
--
----------------------------------------------------------------------

mailto:ari...@natlab.research.philips.com

[bocallag...@gmail.com]

I know this thread is old, but I was curious of this same question. I have two fish tanks, one 20 gallon fresh water and one 40 gallon salt water. I add about 2 gallons of fresh water to my saltwater tank every few days. I do not have to add freshwater to my freshwater tank but once a month when I clean it. The tanks are pretty much side by side in the same room so they endure the same temperature daily. Why would so much water evaporate from the salt water tanks. Anywho, any feedback is greatly appreciated.

Regards,
Chris

[Frank]

https://www.reference.com/science/salt-water-evaporate-faster-fresh-water-623992f1334fa845

[ryandb...@gmail.com]

This is true I have had freshwater tanks for more than 30 years. And I just switched over to saltwater and I cannot believe how many gallons it loses in a week. I am spending so much money on salt. I appreciate your comment because it's so true. After 30 years of doing fishtanks I can tell you that this is a fact. All I can really think of is that there's more water movement. Which maybe causes more of evaporation. Considering I am moving more than 3000 gallons a hour in a 90 gallon fish tank. But I still think it's strange. Take it easy

[dlzc]

Dear aggi...:

The answer is here:
https://www.thespruce.com/the-importance-of-proper-aeration-2921460

Arguments that water does not preferentially evaporate from a free saltwater surface vs. a freshwater surface are moot. Henry's law states that more gas being bubbled through the water, as required to get / keep the oxygen levels up to required levels, will necessarily carry off more water vapor.

If you aerate your freshwater aquaria like you do your salt water aquaria, you will have to add even more water to them. And probably wear those fish out trying to withstand the higher induced currents... ;-) just kidding.

David A. Smith

[Lenny Jacobs]

When reading people's claims that salty tank needs more water, I always
assume both salty and fresh tanks are aerated (and to the same extent.)
Not true? If one is aerated, the other isn't, of course, there is no
comparison.

[Peter Jason]

If salt is xtallizing on the sides of the salt tank, this may act as a
wick, so speeding evaporation.

[dlzc]

Dear Lenny Jacobs:

On Wednesday, September 27, 2017 at 6:36:18 PM UTC-7, Lenny Jacobs wrote:
...

> When reading people's claims that salty tank needs more
> water, I always assume both salty and fresh tanks are
> aerated (and to the same extent.) Not true? If one is
> aerated, the other isn't, of course, there is no
> comparison.

Please read the link provided. To get the oxygen levels up in salt water takes more air. And since salt water is denser, the air is at a higher pressure (Henry's again). It is a function of the mass flow rate of air, being different in the two types of tanks.

I don't assume people are lying, I assume they tell the truth.

David A. Smith

[Alaia]

On Thursday, 2 April 1998 16:00:00 UTC+8, CINDY SMITH wrote:
> Why does salt water evaporate faster than fresh water? My science is a bit
> sketchy. From what I understand (I'm an English major, forgive me), salt water
> evaporates faster because the atomic charge of salt water is different from
> that of fresh water. Salt, I think, also absorbs water? I've heard that
> rubbing salt in an open wound causes the wound to heal faster because salt
> absorbs blood, for example. Salt somehow changes the molecular balance of
> water. Am I on the right track? Can someone recommend a book I can find in a
> library that answers the question? Sorry if the question is too basic.
>
> Thanks!
>
> --
> Cindy Smith
> Spawn of a Jewish Carpenter
> GO AGAINST THE FLOW! \\ _\\\_ _///_ //
> >IXOYE=('> <`)= _<< A Real Live Catholic in Georgia
> c...@dragon.com // /// \\\ \\
>
> Delay not your conversion to the LORD,
> Put it not off from day to day
> Ecclesiasticus/Ben Sira 5:8
>

> Read Catholic.Bible by pointing your news client to vega.vec.net
> Read Catholic.Literature by pointing your news client to vega.vec.net

When NaCl dissolves in water, Na+ and Cl- ions form ion-dipole interaction with water.

As water is evaporated from salt water, less water is available to form ion-dipole interaction with Na+ and Cl- ions. This results more ionic bonds between Na+ and Cl- to be formed, releasing heat energy to further evaporate more water in salt water. Hope this helps.

Alaia
A-level Chemistry teacher in Singapore

[Libor 'Poutnik' Stříž]

Dne 11/12/2017 v 08:47 Alaia napsal(a):

> On Thursday, 2 April 1998 16:00:00 UTC+8, CINDY SMITH wrote:
>> Why does salt water evaporate faster than fresh water? My science is a bit
>> sketchy. From what I understand (I'm an English major, forgive me), salt water
>> evaporates faster because the atomic charge of salt water is different from
>> that of fresh water. Salt, I think, also absorbs water? I've heard that
>> rubbing salt in an open wound causes the wound to heal faster because salt
>> absorbs blood, for example. Salt somehow changes the molecular balance of
>> water. Am I on the right track? Can someone recommend a book I can find in a
>> library that answers the question? Sorry if the question is too basic.
>>
>

> When NaCl dissolves in water, Na+ and Cl- ions form ion-dipole interaction with water.
>
> As water is evaporated from salt water, less water is available to form ion-dipole interaction with Na+ and Cl- ions. This results more ionic bonds between Na+ and Cl- to be formed, releasing heat energy to further evaporate more water in salt water. Hope this helps.
>

>

If water evaporated faster from salt water,
then at the same temperature,
vapour tension over salt water would be higher than over pure water.

But opposite is true.

With higher concentration of sodium chloride,
the water vapour tension decreases
to about 75 % for the saturated salt solution.
That means air closed over the saturated salt solution
has relative humidity near 75 %.

IF you put saltwater and freshwater into a closed container,
freshwater will evaporate and saltwater will absorb the vapour.


--
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.

[Oumati Asami]

In water, sodium and chloride ions are solvated. I don't think ionic
bond between sodium and chloride ions is possible in water unless salt
starts to crystallize out of water. But then, that's ionic bond in
sodium chloride crystal, not in water.

Also, the title is against Raoult's law.

[CRAIG MASON]

Yada, yada, yada...I have an idea, conduct the experiment and find out which one evaporates faster...I could tell you, but then that would defeat the process of learning and finding out for yourself...spoiler alert, a lot of the responses on here are WRONG!

--
*The information in this transmission may contain privileged and
confidential information and is intended only for the use of the person(s)
named above. If you are not the intended recipient, or an employee or agent
responsible for delivering this message to the intended recipient, any
review, dissemination, distribution or duplication of this communication is
strictly prohibited. If you are not the intended recipient, please contact
the sender immediately by reply email and destroy all copies of the
original message.*