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Author Topic: Are there any 2 substance on Earth which have the same boiling point?  (Read 12961 times)

Offline The Scientist

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What do you think? Thanks!


 

Offline Bored chemist

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Yes.
 

Offline Don_1

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Fair enuffski. Clear, concise and right to the point.
 

Offline Bored chemist

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I wondered why anyone asked the question.
 

Offline The Scientist

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What makes you think so Bored Chemist? Care to share? thanks!
 

Offline lightarrow

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There are infinite. The reason is simple: mixing (miscible) liquids in different concentrations, you can get any value between the two liquids' boiling point. For example, if you want a liquid, different than water, which boils at 100°C, you only have to choose two miscible liquids which boiling pointa are, respectively, lower and greater than that of water, let's say n-buthilic alcohol (b.p. = 118°C) and ethilic alcohol (b.p. = 79°C) and you mix them in the appropriate percentages.

If instead you intended two pure compounds, then it depends on the precision required in the b.p. value: the greater the precision, the less compunds you can find with the same b.p. values.
 

Offline Geezer

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What do you think? Thanks!

There are infinite. The reason is simple: mixing (miscible) liquids in different concentrations, you can get any value between the two liquids' boiling point. For example, if you want a liquid, different than water, which boils at 100°C, you only have to choose two miscible liquids which boiling pointa are, respectively, lower and greater than that of water, let's say n-buthilic alcohol (b.p. = 118°C) and ethilic alcohol (b.p. = 79°C) and you mix them in the appropriate percentages.

If instead you intended two pure compounds, then it depends on the precision required in the b.p. value: the greater the precision, the less compunds you can find with the same b.p. values.

You can get even more if you alter the pressure  ;D
 

Offline Bored chemist

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What makes you think so Bored Chemist? Care to share? thanks!

This sort of thing.
Here are some vapour pressure vs temperature curves
http://www.mcallister.com/graphics/vapor4.jpg
Where the curves cross the two materials boil at the same temperature (and pressure).
 

Offline lightarrow

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http://www.mcallister.com/graphics/vapor4.jpg
What do ΣS or ΣP4  mean?
                       S       
 

Offline imatfaal

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Guesswork - combinations (ie sums) of different isotopes or allotropes?  Although ∑Cs is far too low to be carbon.  Perhaps I should wait for BC to explain rather than guess
 

Offline lightarrow

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Guesswork - combinations (ie sums) of different isotopes or allotropes?  Although ∑Cs is far too low to be carbon.  Perhaps I should wait for BC to explain rather than guess
Cs is caesium  :)
 

Offline imatfaal

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Of Course it is.  Doh I was reading it as many Carbons (ie one C, many Cs).  Caesium is pretty low mp/bp isnt it?
 

Offline lightarrow

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Of Course it is.  Doh I was reading it as many Carbons (ie one C, many Cs).  Caesium is pretty low mp/bp isnt it?
Yes (although I don't usually use it to cook spaghetti  ;))
 

Offline Garfed

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Are infinite. The reason is simple: mix (mixed) in different concentrations of liquid, you can get between the two liquids' boiling point of any value...
 

Offline Geezer

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or, you can simply change the boiling point of any substance by altering its pressure. Pressure cookers are quite good at doing that.
 

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