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Topic: boiling water  (Read 8966 times)

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Offline aeacfm

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boiling water
« on: September 01, 2010, 04:35:18 AM »
while doing a test on sea water , i must heat it to 120 oC , when i placed the thermometer in the sea water container and it started to heat the thermometer shows the increase in temperature till 100 oC and after that with further heating the thermometer stopped increasing  , although it graduated to 300 oC untill all water evaporated and it didnot increase!!!!!

can any body explain what is hapening  ? or what is the wrong thing i did ?

Offline typhoon2028

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Re: boiling water
« Reply #1 on: September 01, 2010, 12:04:04 PM »
Was the water boiling?  Were you seeing bubbles?  Was the water being mixed/stirred?

Offline Borek

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Re: boiling water
« Reply #2 on: September 01, 2010, 03:00:38 PM »
Congratulations, you have just learned what is a boiling point.

You can't heat water above 100 deg C, just like you can't heat ice above 0 deg C. This is so basic physics I am in awe someone doesn't know it.

Nitpickers: yes, yes, I know what ebullioscopic constant is, don't mud the water please.
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Offline discodermolide

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Re: boiling water
« Reply #3 on: September 01, 2010, 03:08:55 PM »
Congratulations, you have just learned what is a boiling point.

You can't heat water above 100 deg C, just like you can't heat ice above 0 deg C. This is so basic physics I am in awe someone doesn't know it.

Nitpickers: yes, yes, I know what ebullioscopic constant is, don't mud the water please.
Elevation of boiling point!
Depression of freezing point
So sea water should boil at >100 degreesC
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Offline Borek

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Re: boiling water
« Reply #4 on: September 01, 2010, 03:52:52 PM »
Nitpickers: yes, yes, I know what ebullioscopic constant is, don't mud the water please.
Elevation of boiling point!

Ah, nothing like answering the post without even reading it.

OP doesn't understand why water evaporated before reaching 120 deg C, so at this stage speaking about more advanced concepts is the best way of confusing him, that's why I asked others to NOT post about yet.

Obviously the idea of sitting quiet for a moment is too difficult for some.
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Offline typhoon2028

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Re: boiling water
« Reply #5 on: September 02, 2010, 07:47:19 AM »
Where does it say; "wait some time, let the poster think?"

I would like the poster to list some other observations from the experiment.

Offline aeacfm

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Re: boiling water
« Reply #6 on: September 06, 2010, 01:16:12 PM »
while doing a test on sea water ,
BOREK BASHA
thank you for your interset , that you dont want to confusing me my internet conection was inetrrupted last 3  days ago

here i said the sea water also not sea water alone but sea water contaminated with an acid , also i know that water willnot boil after 100 oc  but at the same time i dont know the reason??? i know about waht you bost about collegative propertiesbut  if  any body know the reason why water cant boil after 100 o c   and also how to make water boil after 100 oc ?

thanks guys

Offline Borek

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Re: boiling water
« Reply #7 on: September 06, 2010, 01:38:25 PM »
Boiling point is CONSTANT - so if you have pure substance you can't boil it at higher temperature than its boiling point. It will boil till it is all vaporised.

Sure, boiling point of mixtures is different and it depends on the pressure and composition - but that's another thing. You can easily calculate concentration of salt necessary for the water to boil at 120 deg C - and it is quite high, much higher than 3.5% in the sea water. When boiling water is removed and concentration of salts grows, but you won't get to 120 till only small fraction of initial solution is left.
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Offline aeacfm

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Re: boiling water
« Reply #8 on: September 06, 2010, 05:27:46 PM »
You can easily calculate concentration of salt necessary for the water to boil at 120 deg C - and it is quite high, much higher than 3.5% in the sea water. When boiling water is removed and concentration of salts grows, but you won't get to 120 till only small fraction of initial solution is left.
how this could be achieved ??
if i want to set the concntration  constant so imus use condensation apparatus  so that i can set the  volume  and concentration of sakts constant ?
also if i want to increase the boiling point physically how could this acieved ?
rmember i wnt hints not the complete answer i know the forum rules

Offline Jorriss

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Re: boiling water
« Reply #9 on: September 06, 2010, 11:48:02 PM »
Are you familiar with colligative properties at all? If so, it's actually fairly straight forward, read about boiling-point elevation.

http://en.wikipedia.org/wiki/Boiling-point_elevation

Offline aeacfm

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Re: boiling water
« Reply #10 on: September 09, 2010, 02:53:22 AM »
Are you familiar with colligative properties at all? If so, it's actually fairly straight forward, read about boiling-point elevation.

http://en.wikipedia.org/wiki/Boiling-point_elevation

 aha , no physical parameter like changing of  pressure of  container will effec the boiling point  thats what i mean by physical mean !!!
can  any body explain ???

Offline aeacfm

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Re: boiling water
« Reply #11 on: September 09, 2010, 02:57:11 AM »


I would like the poster to list some other observations from the experiment.

yes , water  get turbid then  boiled strongly with bubbles . 

Offline aeacfm

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Re: boiling water
« Reply #12 on: September 22, 2010, 08:50:08 AM »
ok , here is another thing do any body know the tempertaure at which salt starts to separate from sea water

Offline sluijten

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Re: boiling water
« Reply #13 on: September 24, 2010, 01:28:45 AM »
as in crystallize?

Offline aeacfm

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Re: boiling water
« Reply #14 on: September 25, 2010, 09:38:01 AM »
i mean when you heat sea water it starts to precipitate its salt i am asking about the strting temperatuer for that

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