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Topic: The evaporation of water with dissolved salt in it  (Read 5619 times)

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Offline watchayakan

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The evaporation of water with dissolved salt in it
« on: November 22, 2006, 12:01:47 AM »
Alright.  I'm doing my Group IV project (if you know what it is for, you know the kind of plight I am in), and neither my teacher nor I can explain what is going on.  It started out with me simply testing the solubility of salt at different temperatures, but, when it came out of the drying oven, the beaker had white all over the inside on the walls and even some on the outside, but there was very little clumped in the bottom.  We thought it was because she put the temperature too high, but even at 80 degrees Celsius it did so, so she suggested I do my experiment on that.

Anyways, I've done a fiair amount of scenarios, and it seems to go up the walls of the beaker more readily if it is glass rather than plastic, and at about 0.50g it barely goes up a 400mL beaker.  I was hoping someone had some information as why this is happening.  I've settled on experimenting with 25 mL of water at room temperature in a 400 mL glass beaker.  I am using 0.50-1.50g of salt, with increments of 0.25g.  I stir the salt water before putting it in teh oven, and I set the oven to 70 degrees Celsius.  The variable, then, is the concentration of salt, so I am hoping that a good reason can be given.

My teacher told me to try to find a reason on the Internet, but all I could really find was the Weissenberg effect, which I don't think is the case.  I think it may have somethign to do with the water evaporating then condensating on the walls of the beaker, but I am just not sure.  Thank you in advance.

Offline Mitch

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Re: The evaporation of water with dissolved salt in it
« Reply #1 on: November 22, 2006, 01:08:06 AM »
Place the salt water in solution and don't heat it, just let it evaporate through thanksgiving and see what happens when you come back. See if you can prove your initial hypothesis.
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Offline Borek

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Re: The evaporation of water with dissolved salt in it
« Reply #2 on: November 22, 2006, 03:45:15 AM »
What salt?
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Offline AWK

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Re: The evaporation of water with dissolved salt in it
« Reply #3 on: November 22, 2006, 04:51:38 AM »
Such a behaviour often shows Na2CO3
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Offline watchayakan

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Re: The evaporation of water with dissolved salt in it
« Reply #4 on: November 22, 2006, 09:04:51 PM »
NaCl; sorry for not being specific.  I'd really try that out, Mitch, but I don't have enough equipment to complete that before the lab is due, especially since my current trials won't be done until Friday morning.  Some reading material that I could have easy access to, such as an article on the Internet or a chapter in a book (or the whole book itself, I guess) that most public libraries contain, would be helpful.  I do know the Socratic model you try to reflect, Mitch, but even just references to articles or books would be of great help.

Offline Gerard

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Re: The evaporation of water with dissolved salt in it
« Reply #5 on: November 23, 2006, 06:18:12 AM »
i suggest before you asked a certain question based on empirical situations you should dive into references i suggets you read solid solubilty by any physical chemistry books
i suggets you read the books of maron and lando or the one by atkins or for further reading read the books chemical and engineering thermodynamics by sandler...
if you cant get anything that's the time you ask your questions
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Offline DrCMS

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Re: The evaporation of water with dissolved salt in it
« Reply #6 on: November 23, 2006, 06:39:05 AM »
Am i missing something here isn't Group IV - C, Si, Ge, Sn, and Pb?

Offline watchayakan

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Re: The evaporation of water with dissolved salt in it
« Reply #7 on: November 24, 2006, 08:33:22 PM »
I didn't mean Group IV A or B; it's an experiment I have to do.

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