Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: aeacfm on September 01, 2010, 04:35:18 AM
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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 ?
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Was the water boiling? Were you seeing bubbles? Was the water being mixed/stirred?
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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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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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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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Where does it say; "wait some time, let the poster think?"
I would like the poster to list some other observations from the experiment.
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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
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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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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
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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
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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 ???
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I would like the poster to list some other observations from the experiment.
yes , water get turbid then boiled strongly with bubbles .
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ok , here is another thing do any body know the tempertaure at which salt starts to separate from sea water
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as in crystallize?
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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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i mean when you heat sea water it starts to precipitate its salt i am asking about the strting temperatuer for that
No idea about the temperature, but the salt will start to precipitate out when the saturation concentration at that temperature is reached. Try Google, there must be solubility curves somewhere.