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Half way down the page it states 260mbar is 26.39kPa. This is at odds with the article for Pascals, which states that 1 bar = 100,000 Pascals. — Preceding unsigned comment added by 86.160.105.124 ( talk) 18:37, 2 June 2011 (UTC)
There should be discussion of the phenomenon of boiling point elevation in solutions, that the boiling point of salt or sugar water is higher than the boiling point of pure water, and why. -- Dominus 05:54 Apr 20, 2003 (UTC)
Looking at the definition of boiling and the bit about adding heat not changing the temperature, would a better definition for boiling point be the maximum temperature a a substance can be increased to as a liquid? Martschink 18:04, 24 Jun 2005 (UTC)
What is the difference between heat and temperature?
A lot of different sites give different numbers on the boiling points of various elements, particularly Rhenium and Tungsten. This site gives Re's as 5627 and W's as 5660 Kelvin. Wikipedia currently has Re at 5869 and W at 5828 Kelvin. Chemicalelements.com has Re at 5900.15 °K, W at 5933.15 °K. So who do we believe? There's a disagreement that ranges almost three hundred degrees Kelvin here. Mr. Billion 17:49, 24 Jun 2005 (UTC)
The first sentence states:
The boiling point of a substance is the maximum temperature at which a liquid can remain a liquid.
That is incorrect. There is no such thing as "The boiling point". Every liquid has different vapor pressures at different temperatures. Graphs of vapor pressure versus temperature of a liquid are called "vapor pressure curves". Thus, any liquid may have an infinite number of boiling points since such curves have an infinite number of points. The correct definition of a liquid's boiling point is "the temperature at which the vapor pressure of the liquid equals the pressure surrounding the liquid." Thus, a liquid in a vacuum environment has a lower boiling point than when the liquid is at atmospheric pressure. And a liquid in a high pressure environment has a higher boiling point than when the liquid is at atmospheric pressure. That's how high-pressure steam is made ... by boiling water that is at a high pressure. This is elementary, high school chemistry!
The second paragraph in the article states:
A somewhat clearer (and perhaps more useful) definition of boiling point is "the temperature at which the vapor pressure of the liquid equals the atmospheric pressure."
That is also incorrect. That only defines what is called the "atmospheric boiling point" or the "normal boiling point" ... which is only one of the infinite number of boiling points a liquid may have. The title of this article is "Boiling point" ... it is not "Atmospheric boiling point".
This article was first created in September of 2001, which is over 6 years ago. It is mind-boggling to think that the above definitions were never questioned during all that time. This isn't rocket science or quantum physics, it's simple high school chemistry.
I regret having to be so blunt, but much of this article deserves that bluntness. Wikipedians who don't really understand simple chemistry and physical chemistry should not edit this article. - mbeychok 08:15, 6 October 2007 (UTC)
Can someone please explain to me the difference between steam point and boiling point?
Or is it the same thing? well what is the boiling point in celsius please —Preceding unsigned comment added by 124.176.44.153 ( talk) 05:09, 17 May 2008 (UTC)
never mind i don't want to anymore
My kid looked up the defintion of boiling point here on Wikipedia and got a headache. This is overly complicated. Give a basic laymen term definition then go into the doctoral-orgasmic Ph.D. bulls**t. —Preceding unsigned comment added by 71.188.231.28 ( talk) 23:32, 17 February 2010 (UTC)
what is principle of boiling point and melting point? —Preceding unsigned comment added by 115.248.151.2 ( talk) 10:46, 28 January 2011 (UTC)
Hi. Wikipedia is very useful in providing data, such as the boiling point of numerous chemicals. Does anyone know if those are normal boiling points or standard boiling points? For some things, it does make a difference. Thank you! El Zarco 08:22, 27 November 2011 (UTC)
This article is skimpy. A number of factors influence boiling points, such as atomic weight of elements and types of bonding of compounds. It would be nice to have a section discussing these factors. — Preceding unsigned comment added by Skysong263 ( talk • contribs) 22:44, 18 December 2011 (UTC)
Hello,
I was just using the Clausius-Clapeyron equation on this page and I believe you may have missed out a variable in the equation, which you stated as:
T_B = \Bigg(\frac{\,R\,\ln(P_0)}{\Delta H_{vap}}+\frac{1}{T_0}\Bigg)^{-1}
But it is without the relative pressure calculation "(P0/P)" that is requisite. It should therefore be:
T_B = \Bigg(\frac{\,R\,\ln(\frac{P_0}{P})}{\Delta H_{vap}}+\frac{1}{T_0}\Bigg)^{-1}
If I have misunderstood anything and this was intentional for some reason or another, I apologise, I am not an expert on chemistry or thermodynamics.
NiklasZ ( talk) 11:29, 26 March 2012 (UTC)
198.177.184.17 ( talk) 23:36, 5 February 2015 (UTC) Typo? The variable definition states: "P = is the vapour pressure of the liquid at the pressure of interest . . ." Shouldn't it state that P = the vapor pressure of the liquid at the temperature of interest (temp not pressure)? Vapor pressure is a function of temperature. As stated it does not seem to make sense. Also, the equals sign & the word "is" are redundant - delete the word "is".
I've added a few parts from this article at heat transfer, here. Prokaryotes ( talk) 16:31, 5 April 2014 (UTC)
To
User:Materialscientist,
I think the addition of the latest graph, which is the image
File:Boiling point vs molar mass graph.png, is a very good addition for the article. However, it has been placed in the article at too small a size and is difficult to make out easily. I think I'll enlarge it some day. It shows the effect of
molar mass and compound
polarity on a compound's boiling point. It might be nice to put in separately a little information on
isomers too.
H Padleckas (
talk) 12:16, 10 June 2014 (UTC)
As of 3/5/2015, reference 7 points to a McGraw-Hill textbook appendix instead of the actual IUPAC publication, which can be found here on pages 1246-1247 132.170.57.13 ( talk) 19:59, 5 March 2015 (UTC)
Need a reference for the following quote:
"For example, water boils at 100 °C (212 °F) at sea level, but at 93.4 °C (200.1 °F) at 2,000 metres (6,600 ft) altitude"
But the United States Dept of Agriculture states "With each 500-feet increase in elevation, the boiling point of water is lowered by just under 1 °F" [1]
Therefore, at 6600 feet, water boils at 208 F Therefore, at 2km, water boils at 97.8 Celsius
Cleverwater ( talk) 14:34, 6 November 2016 (UTC)
This is the
talk page for discussing improvements to the
Boiling point article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This
level-5 vital article is rated B-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||
|
Half way down the page it states 260mbar is 26.39kPa. This is at odds with the article for Pascals, which states that 1 bar = 100,000 Pascals. — Preceding unsigned comment added by 86.160.105.124 ( talk) 18:37, 2 June 2011 (UTC)
There should be discussion of the phenomenon of boiling point elevation in solutions, that the boiling point of salt or sugar water is higher than the boiling point of pure water, and why. -- Dominus 05:54 Apr 20, 2003 (UTC)
Looking at the definition of boiling and the bit about adding heat not changing the temperature, would a better definition for boiling point be the maximum temperature a a substance can be increased to as a liquid? Martschink 18:04, 24 Jun 2005 (UTC)
What is the difference between heat and temperature?
A lot of different sites give different numbers on the boiling points of various elements, particularly Rhenium and Tungsten. This site gives Re's as 5627 and W's as 5660 Kelvin. Wikipedia currently has Re at 5869 and W at 5828 Kelvin. Chemicalelements.com has Re at 5900.15 °K, W at 5933.15 °K. So who do we believe? There's a disagreement that ranges almost three hundred degrees Kelvin here. Mr. Billion 17:49, 24 Jun 2005 (UTC)
The first sentence states:
The boiling point of a substance is the maximum temperature at which a liquid can remain a liquid.
That is incorrect. There is no such thing as "The boiling point". Every liquid has different vapor pressures at different temperatures. Graphs of vapor pressure versus temperature of a liquid are called "vapor pressure curves". Thus, any liquid may have an infinite number of boiling points since such curves have an infinite number of points. The correct definition of a liquid's boiling point is "the temperature at which the vapor pressure of the liquid equals the pressure surrounding the liquid." Thus, a liquid in a vacuum environment has a lower boiling point than when the liquid is at atmospheric pressure. And a liquid in a high pressure environment has a higher boiling point than when the liquid is at atmospheric pressure. That's how high-pressure steam is made ... by boiling water that is at a high pressure. This is elementary, high school chemistry!
The second paragraph in the article states:
A somewhat clearer (and perhaps more useful) definition of boiling point is "the temperature at which the vapor pressure of the liquid equals the atmospheric pressure."
That is also incorrect. That only defines what is called the "atmospheric boiling point" or the "normal boiling point" ... which is only one of the infinite number of boiling points a liquid may have. The title of this article is "Boiling point" ... it is not "Atmospheric boiling point".
This article was first created in September of 2001, which is over 6 years ago. It is mind-boggling to think that the above definitions were never questioned during all that time. This isn't rocket science or quantum physics, it's simple high school chemistry.
I regret having to be so blunt, but much of this article deserves that bluntness. Wikipedians who don't really understand simple chemistry and physical chemistry should not edit this article. - mbeychok 08:15, 6 October 2007 (UTC)
Can someone please explain to me the difference between steam point and boiling point?
Or is it the same thing? well what is the boiling point in celsius please —Preceding unsigned comment added by 124.176.44.153 ( talk) 05:09, 17 May 2008 (UTC)
never mind i don't want to anymore
My kid looked up the defintion of boiling point here on Wikipedia and got a headache. This is overly complicated. Give a basic laymen term definition then go into the doctoral-orgasmic Ph.D. bulls**t. —Preceding unsigned comment added by 71.188.231.28 ( talk) 23:32, 17 February 2010 (UTC)
what is principle of boiling point and melting point? —Preceding unsigned comment added by 115.248.151.2 ( talk) 10:46, 28 January 2011 (UTC)
Hi. Wikipedia is very useful in providing data, such as the boiling point of numerous chemicals. Does anyone know if those are normal boiling points or standard boiling points? For some things, it does make a difference. Thank you! El Zarco 08:22, 27 November 2011 (UTC)
This article is skimpy. A number of factors influence boiling points, such as atomic weight of elements and types of bonding of compounds. It would be nice to have a section discussing these factors. — Preceding unsigned comment added by Skysong263 ( talk • contribs) 22:44, 18 December 2011 (UTC)
Hello,
I was just using the Clausius-Clapeyron equation on this page and I believe you may have missed out a variable in the equation, which you stated as:
T_B = \Bigg(\frac{\,R\,\ln(P_0)}{\Delta H_{vap}}+\frac{1}{T_0}\Bigg)^{-1}
But it is without the relative pressure calculation "(P0/P)" that is requisite. It should therefore be:
T_B = \Bigg(\frac{\,R\,\ln(\frac{P_0}{P})}{\Delta H_{vap}}+\frac{1}{T_0}\Bigg)^{-1}
If I have misunderstood anything and this was intentional for some reason or another, I apologise, I am not an expert on chemistry or thermodynamics.
NiklasZ ( talk) 11:29, 26 March 2012 (UTC)
198.177.184.17 ( talk) 23:36, 5 February 2015 (UTC) Typo? The variable definition states: "P = is the vapour pressure of the liquid at the pressure of interest . . ." Shouldn't it state that P = the vapor pressure of the liquid at the temperature of interest (temp not pressure)? Vapor pressure is a function of temperature. As stated it does not seem to make sense. Also, the equals sign & the word "is" are redundant - delete the word "is".
I've added a few parts from this article at heat transfer, here. Prokaryotes ( talk) 16:31, 5 April 2014 (UTC)
To
User:Materialscientist,
I think the addition of the latest graph, which is the image
File:Boiling point vs molar mass graph.png, is a very good addition for the article. However, it has been placed in the article at too small a size and is difficult to make out easily. I think I'll enlarge it some day. It shows the effect of
molar mass and compound
polarity on a compound's boiling point. It might be nice to put in separately a little information on
isomers too.
H Padleckas (
talk) 12:16, 10 June 2014 (UTC)
As of 3/5/2015, reference 7 points to a McGraw-Hill textbook appendix instead of the actual IUPAC publication, which can be found here on pages 1246-1247 132.170.57.13 ( talk) 19:59, 5 March 2015 (UTC)
Need a reference for the following quote:
"For example, water boils at 100 °C (212 °F) at sea level, but at 93.4 °C (200.1 °F) at 2,000 metres (6,600 ft) altitude"
But the United States Dept of Agriculture states "With each 500-feet increase in elevation, the boiling point of water is lowered by just under 1 °F" [1]
Therefore, at 6600 feet, water boils at 208 F Therefore, at 2km, water boils at 97.8 Celsius
Cleverwater ( talk) 14:34, 6 November 2016 (UTC)