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What's the story on solder these days?
Ian Wade wrote: What kind of solder should one use these days? Find out whether the components are RoHS compliant. If they aren't, your old solder will do. If they are, you'll need lead-free solder. 73 Mike G4KFK |
What's the story on solder these days?
In message , Ian Wade
writes I am looking into the possibility of buying a kit to assemble, but have come across this statement in the warranty Ts and Cs: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The use of acid-core solder, water-soluble flux solder, or any corrosive or conductive flux or solvent will void this warranty in its entirety. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ My current reel of no-name solder is several years old, and I have no idea whether it complies or not (but I suspect not). What kind of solder should one use these days? Hi Ian, It may or may not help, but this is a subject that comes up regularly on the Elecraft reflector. So much so they have a separate section on the web site. See if this helps: http://www.elecraft.com/solder_sources.htm Trev G3ZYY -- Trevor Day UKSMG #217 www.uksmg.org |
What's the story on solder these days?
In message . com, The
Radio Amateur Formerly Known As G4KFK writes Ian Wade wrote: What kind of solder should one use these days? Find out whether the components are RoHS compliant. If they aren't, your old solder will do. If they are, you'll need lead-free solder. 73 Mike G4KFK Seems you need to ignore my link Ian if thats the case. Sri Trev -- Trevor Day UKSMG #217 www.uksmg.org |
What's the story on solder these days?
Trevor Day wrote: Seems you need to ignore my link Ian if thats the case. Or, if the kit came from the USA, he could ignore what I said :-) The Murraycans aren't in the EEC (or whatever it's called this week), so I don't s'pose they're too worried about complying with RoHS. 73 Mike G4KFK |
What's the story on solder these days?
Hi Ian
I suspect they are talking about plumbers soldering methods that use such fluxes etc. Rosin core or the more current electronic fluxes will be fine, which is probably what you roll is. There is also the move to lead free. These joints always look real bad! Cheers Bob VK2YQA (who works in a production RF/SMD environment..) Ian Wade wrote: What kind of solder should one use these days? |
What's the story on solder these days?
Lead free solder is impossible as solder is an alloy of lead and tin.
Anything else would not be solder! "The Radio Amateur Formerly Known As G4KFK" wrote in message ups.com... Ian Wade wrote: What kind of solder should one use these days? Find out whether the components are RoHS compliant. If they aren't, your old solder will do. If they are, you'll need lead-free solder. 73 Mike G4KFK |
What's the story on solder these days?
In article , "G8ASO (.¿.)
© T" writes "The Radio Amateur Formerly Known As G4KFK" wrote in message ups.com... Ian Wade wrote: What kind of solder should one use these days? Find out whether the components are RoHS compliant. If they aren't, your old solder will do. If they are, you'll need lead-free solder. Lead free solder is impossible as solder is an alloy of lead and tin. Anything else would not be solder! Wrong again, see: http://www.askoxford.com/concise_oed/solder?view=uk http://www.chemicool.com/definition/solder.html -- Ian G8ILZ |
What's the story on solder these days?
Prometheus wrote:
Lead free solder is impossible as solder is an alloy of lead and tin. Anything else would not be solder! Wrong again, see: http://www.askoxford.com/concise_oed/solder?view=uk http://www.chemicool.com/definition/solder.html And you will probably need to replace your soldering iron too. -- huLLy Tel: 07976 123278 villageidiot(at)sheepandmeths.co.uk ICQ 136-987-925 |
What's the story on solder these days?
In article , huLLy
writes Prometheus wrote: Lead free solder is impossible as solder is an alloy of lead and tin. Anything else would not be solder! Wrong again, see: http://www.askoxford.com/concise_oed/solder?view=uk http://www.chemicool.com/definition/solder.html And you will probably need to replace your soldering iron too. Unless it's a decent TCP in which case you might only need more mass rather than a higher temperature. One important note; do not mix solder types. -- Ian G8ILZ |
What's the story on solder these days?
G8ASO (.¿.) © T wrote: Lead free solder is impossible as solder is an alloy of lead and tin. Anything else would not be solder! OED "Solder. n. Fusible alloy used to join less fusible metals or wires." |
What's the story on solder these days?
Ian Wade wrote:
I am looking into the possibility of buying a kit to assemble, but have come across this statement in the warranty Ts and Cs: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The use of acid-core solder, water-soluble flux solder, or any corrosive or conductive flux or solvent will void this warranty in its entirety. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ My current reel of no-name solder is several years old, and I have no idea whether it complies or not (but I suspect not). What kind of solder should one use these days? While lead free solder is the norm now... The use of solder with lead is still permitted for... Private use. Repair of circuit boards that have leaded solder on them and a few other situations that I can't recall. Lead based solder looks likely to be on the market for some time to come. Dave |
What's the story on solder these days?
On Sun, 30 Jul 2006 01:31:49 -0700, The Radio Amateur Formerly Known As
G4KFK wrote: Ian Wade wrote: What kind of solder should one use these days? Find out whether the components are RoHS compliant. If they aren't, your old solder will do. If they are, you'll need lead-free solder. I thought it was the other way round - leaded solder is ok with all component types but lead free solder shouldn't be used with components where the leads have lead in the plating. All the manufacturers I've checked with say leaded solder is ok with RoHS compliant parts. Steve |
What's the story on solder these days?
Steve wrote: I thought it was the other way round - leaded solder is ok with all component types but lead free solder shouldn't be used with components where the leads have lead in the plating. All the manufacturers I've checked with say leaded solder is ok with RoHS compliant parts. From a compliance point of view, you can't mix either type, either way around. If you use leaded solder to assemble (or repair) an RoHS compliant device, it won't be RoHS compliant. |
What's the story on solder these days?
"The Radio Amateur Formerly Known As G4KFK" wrote in message ups.com... Ian Wade wrote: What kind of solder should one use these days? Find out whether the components are RoHS compliant. If they aren't, your old solder will do. If they are, you'll need lead-free solder. 73 Mike G4KFK I don't think there is any practical reason why you cannot use traditional lead based solder on RoHS components, is there? Its just another barmy EU regulation to make our lives difficult. There may be aguements the other way round - lead free solder requires a significantly higher temperature and components which are not specified to work with it could be damaged during assembly - I guess... Martin (G8FXC) |
What's the story on solder these days?
"MAB" me@here wrote in message
... "The Radio Amateur Formerly Known As G4KFK" wrote in message ups.com... Ian Wade wrote: What kind of solder should one use these days? Find out whether the components are RoHS compliant. If they aren't, your old solder will do. If they are, you'll need lead-free solder. 73 Mike G4KFK I don't think there is any practical reason why you cannot use traditional lead based solder on RoHS components, is there? Its just another barmy EU regulation to make our lives difficult. There may be augments the other way round - lead free solder requires a significantly higher temperature and components which are not specified to work with it could be damaged during assembly - I guess... Martin (G8FXC) It's all down to interfering busybodies who demand that anything considered harmless must be curtailed. Fumes from leaded solder especially in a confined area can be considered highly toxic and if 'sniffed in' in large amounts can send you loopy at best and kill you at worst. Therefore RoSH was dreamt up by someone with far too much time on their hands to try to make everyone's life safer. Makes you wonder why they don't concern themselves with the biggest killer of all time.. smoking.. well, the answer to that is simple... MONEY. 73' Graham (Living in a molly-coddled world. British Bulldog in the playground?...oooh noo far too dangerous, the kids may bump into each other.. shock horror) -- -.-. -... / .-. .- -.. .. --- Radio is only a Hobby. Don't let it rule your life... 73/51 - Graham, 26-Golf Charlie-19 (www.open-channel.co.uk) |
What's the story on solder these days?
The Magnum wrote:
Fumes from leaded solder especially in a confined area can be considered highly toxic and if 'sniffed in' in large amounts can send you loopy at best and kill you at worst. I didn't know Beanie done a lot of construction? And, considering we haven't heard from him in a while.... hmm? |
What's the story on solder these days?
MAB wrote: I don't think there is any practical reason why you cannot use traditional lead based solder on RoHS components, is there? Of course - from a practical viewpoint, it will work fine. From a compliance viewpoint though, you end up with a product labelled to the effect that it does not contain lead (or other harmful substances), that does in fact contain lead. |
What's the story on solder these days?
The Magnum wrote: It's all down to interfering busybodies who demand that anything considered harmless must be curtailed. Fumes from leaded solder especially in a confined area can be considered highly toxic and if 'sniffed in' in large amounts can send you loopy at best and kill you at worst. Shirley the fumes are from the flux, not the solder? RoHS is to address heavy metals in post-consumer waste re-entering the environment via landfill sites. |
What's the story on solder these days?
On Sun, 30 Jul 2006 23:45:07 -0700, The Radio Amateur Formerly Known As
G4KFK wrote: Steve wrote: I thought it was the other way round - leaded solder is ok with all component types but lead free solder shouldn't be used with components where the leads have lead in the plating. All the manufacturers I've checked with say leaded solder is ok with RoHS compliant parts. From a compliance point of view, you can't mix either type, either way around. If you use leaded solder to assemble (or repair) an RoHS compliant device, it won't be RoHS compliant. Yes - I meant my comment only about the metallurgy of the joint. As I understand it, private individuals aren't expected to abide by RoHS and it won't be applied to personal (as opposed to business) sales. Steve |
What's the story on solder these days?
Wel,, it depends on which Pb-Free alloy is chosen. There is no
industry-agreed standard composition. In general there are two competing systems: Tin-Silver (Sn-Ag) and Tin-Bismith (Sn-Bi). If Sn-Ag is used, then mixing standard Lead-Tin (Pb-Sn)with it is OK. If Sn-Bi is used, however, there is a low-melting ternary Pb-Sn-Bi compound that can cause you problems. Not all electronic component manufacturers have decided against Sn-Bi (it costs less than Sn-Ag). So the key is determining you have Sn-Ag solder on your Pb-Free component (or in some cases, no solder on the component). Roger "Steve" wrote in message ... On Sun, 30 Jul 2006 23:45:07 -0700, The Radio Amateur Formerly Known As G4KFK wrote: Steve wrote: I thought it was the other way round - leaded solder is ok with all component types but lead free solder shouldn't be used with components where the leads have lead in the plating. All the manufacturers I've checked with say leaded solder is ok with RoHS compliant parts. From a compliance point of view, you can't mix either type, either way around. If you use leaded solder to assemble (or repair) an RoHS compliant device, it won't be RoHS compliant. Yes - I meant my comment only about the metallurgy of the joint. As I understand it, private individuals aren't expected to abide by RoHS and it won't be applied to personal (as opposed to business) sales. Steve |
What's the story on solder these days?
"The Radio Amateur Formerly Known As G4KFK" wrote in
message ps.com... The Magnum wrote: It's all down to interfering busybodies who demand that anything considered harmless must be curtailed. Fumes from leaded solder especially in a confined area can be considered highly toxic and if 'sniffed in' in large amounts can send you loopy at best and kill you at worst. Shirley the fumes are from the flux, not the solder? Yes there are fumes from the flux, obviously. The lead content in the fumes from molten solder is still toxic. It is another of the reasons (apart from cost) that you won't find lead pipe in new houses or lead based paint. RoHS is to address heavy metals in post-consumer waste re-entering the environment via landfill sites. Yes it is. But I thought the waste side of the proposal was covered by the WEEE regulations and the RoSH covered the fact it is a Hazardous material to use .. period.(Please excuse the crass Americanism ;o) 73' Graham -- -.-. -... / .-. .- -.. .. --- Radio is only a Hobby. Don't let it rule your life... 73/51 - Graham, 26-Golf Charlie-19 (www.open-channel.co.uk) |
What's the story on solder these days?
On Mon, 31 Jul 2006 07:34:50 -0500, Roger wrote:
Wel,, it depends on which Pb-Free alloy is chosen. There is no industry-agreed standard composition. In general there are two competing systems: Tin-Silver (Sn-Ag) and Tin-Bismith (Sn-Bi). If Sn-Ag is used, then mixing standard Lead-Tin (Pb-Sn)with it is OK. If Sn-Bi is used, however, there is a low-melting ternary Pb-Sn-Bi compound that can cause you problems. Not all electronic component manufacturers have decided against Sn-Bi (it costs less than Sn-Ag). So the key is determining you have Sn-Ag solder on your Pb-Free component (or in some cases, no solder on the component). Thanks for that - I haven't encountered anything with Bismuth yet. Plain tin plating seems most common amongst what I handle. Steve |
What's the story on solder these days?
On Mon, 31 Jul 2006 03:43:41 -0700, The Radio Amateur Formerly Known As
G4KFK wrote: The Magnum wrote: It's all down to interfering busybodies who demand that anything considered harmless must be curtailed. Fumes from leaded solder especially in a confined area can be considered highly toxic and if 'sniffed in' in large amounts can send you loopy at best and kill you at worst. Shirley the fumes are from the flux, not the solder? RoHS is to address heavy metals in post-consumer waste re-entering the environment via landfill sites. Which makes it very frustrating that the net aimed at mobile phones and MP3 players turned into a sieve to encompass low volume long life items in fixed installations and even church organs.... Steve |
What's the story on solder these days?
The Magnum wrote:
"The Radio Amateur Formerly Known As G4KFK" wrote in message ps.com... The Magnum wrote: It's all down to interfering busybodies who demand that anything considered harmless must be curtailed. Fumes from leaded solder especially in a confined area can be considered highly toxic and if 'sniffed in' in large amounts can send you loopy at best and kill you at worst. Shirley the fumes are from the flux, not the solder? Yes there are fumes from the flux, obviously. The lead content in the fumes from molten solder is still toxic. It is another of the reasons (apart from cost) that you won't find lead pipe in new houses or lead based paint. except that there is NO LEAD CONTENT IN THE FLUX FUMES. Lead does not vaporize until much higher temperature than soldering temperatures... RoHS is to address heavy metals in post-consumer waste re-entering the environment via landfill sites. Yes it is. But I thought the waste side of the proposal was covered by the WEEE regulations and the RoSH covered the fact it is a Hazardous material to use .. period.(Please excuse the crass Americanism ;o) 73' Graham |
What's the story on solder these days?
Now are you seriously trying to tell me there are NO traces of lead in the flux fumes? Are you certain about that? I think you should ask Nick about that From what I hear he just looks at solder and it runs No doubt because of the heat DieSea |
What's the story on solder these days?
"litle ole me" ""nobody \"@ nowhere.com" wrote in message ... except that there is NO LEAD CONTENT IN THE FLUX FUMES. Lead does not vaporize until much higher temperature than soldering temperatures... Now are you seriously trying to tell me there are NO traces of lead in the flux fumes? Are you certain about that? 73' Graham -- -.-. -... / .-. .- -.. .. --- Radio is only a Hobby. Don't let it rule your life... 73/51 - Graham, 26-Golf Charlie-19 (www.open-channel.co.uk) |
What's the story on solder these days?
"DieSea" wrote in message
... Now are you seriously trying to tell me there are NO traces of lead in the flux fumes? Are you certain about that? I think you should ask Nick about that From what I hear he just looks at solder and it runs No doubt because of the heat DieSea LOL. In all seriousness though there must be an element of lead in the fumes no matter what the supposed vaporisation level of the solder is. As in much the same way as harmful levels of lead were found in water running through lead pipes. These pipes weren't at vaporisation temperature to pass small amounts into the water running through it. Likewise the flux core in the lead solder would 'surely' have a concentration of lead in it no matter how insignificant an amount it might be. 73' Graham -- -.-. -... / .-. .- -.. .. --- Radio is only a Hobby. Don't let it rule your life... 73/51 - Graham, 26-Golf Charlie-19 (www.open-channel.co.uk) |
What's the story on solder these days?
The Magnum wrote:
"DieSea" wrote in message ... Now are you seriously trying to tell me there are NO traces of lead in the flux fumes? Are you certain about that? I think you should ask Nick about that From what I hear he just looks at solder and it runs No doubt because of the heat DieSea LOL. In all seriousness though there must be an element of lead in the fumes no matter what the supposed vaporisation level of the solder is. As in much the same way as harmful levels of lead were found in water running through lead pipes. These pipes weren't at vaporisation temperature to pass small amounts into the water running through it. Likewise the flux core in the lead solder would 'surely' have a concentration of lead in it no matter how insignificant an amount it might be. 73' Graham yes, that would be called leaching, and lead does not leach into the air. it would also be due to water 'erosion' of the solder. it IS rather soft.. yes, I am serious. no lead in the solder fumes. if there was lead in the solder fumes, then most every ham end electronic tinkerer would have serious health problems. (hey, wait a minute... ;- just kidding. no lead in solder fumes.) |
What's the story on solder these days?
In all seriousness though there must be an element of lead in the fumes no matter what the supposed vaporisation level of the solder is. As in much the same way as harmful levels of lead were found in water running through lead pipes. These pipes weren't at vaporisation temperature to pass small amounts into the water running through it. Likewise the flux core in the lead solder would 'surely' have a concentration of lead in it no matter how insignificant an amount it might be. 73' Graham yes, that would be called leaching, and lead does not leach into the air. it would also be due to water 'erosion' of the solder. it IS rather soft.. yes, I am serious. no lead in the solder fumes. if there was lead in the solder fumes, then most every ham end electronic tinkerer would have serious health problems. Ahhhhhhh That explains it And Confirms the ramblings of MattD Where is he by the way Someone hasn't filled is boots with lead and heaved him overboard I hope Unlike Nick he will be missed DieSea |
What's the story on solder these days?
DieSea wrote: Someone hasn't filled is boots with lead and heaved him overboard I hope Sorry, but that's no longer possible. RoHS came into force on July 1st. They would have to have filled his boots with non-toxic lead substitute. As for heaving somebody overboard, please remember that Dihydrogen Monoxide restrictions will come into force as of September 1st. Please see http://www.dhmo.org/ for more details. |
What's the story on solder these days?
The Radio Amateur Formerly Known As G4KFK wrote: (snip) As for heaving somebody overboard, please remember that Dihydrogen Monoxide restrictions will come into force as of September 1st. Please see http://www.dhmo.org/ for more details. Good news for the soap-dodgers, then. 8-) |
What's the story on solder these days?
Steve wrote: (snip) Which makes it very frustrating that the net aimed at mobile phones and MP3 players turned into a sieve to encompass low volume long life items in fixed installations and even church organs.... that's much the normative behaviour of our interpretive legislators - take a simple EU directive, bloat it out of all proportion, then when there's a complaint, it can be pinned on those nasty EU beaurocrats. In the meantime they'll get knighthoods for being so diligent - much easier than polishing the handle on the big front door.. Ah, it's medication time. Nurse!!! |
What's the story on solder these days?
In article , litle ole me
writes except that there is NO LEAD CONTENT IN THE FLUX FUMES. Lead does not vaporize until much higher temperature than soldering temperatures... There will be lead in the fumes; molecules regularly detach themselves and float off into the air from liquids (and can also do so for some solids under certain conditions) at well below the vaporization temperature, perhaps you have not noticed that water at room temperature will evaporate, remember: molten is a liquid. This is why mercury spills are such a problem, and why several years ago laboratories (schools etc.) had to incur expense having floors lifted and mercury removed by special vacuum cleaners, and using mercury vapour detectors to variety 'safe' levels. A few weeks ago I had to clean a spill caused by a broken thermometer from a cupboard. -- Ian G8ILZ |
What's the story on solder these days?
Prometheus wrote:
In article , litle ole me writes except that there is NO LEAD CONTENT IN THE FLUX FUMES. Lead does not vaporize until much higher temperature than soldering temperatures... There will be lead in the fumes; molecules regularly detach themselves and float off into the air from liquids (and can also do so for some solids under certain conditions) at well below the vaporization temperature, perhaps you have not noticed that water at room temperature will evaporate, remember: molten is a liquid. This is why mercury spills are such a problem, and why several years ago laboratories (schools etc.) had to incur expense having floors lifted and mercury removed by special vacuum cleaners, and using mercury vapour detectors to variety 'safe' levels. A few weeks ago I had to clean a spill caused by a broken thermometer from a cupboard. so, what protection should we use when soldering? how much lead would have been ingested? Having worked in a production and engineering environment for many years, I would think that were there any risk of lead in solder fumes, there would be HUGE guidelines from the EPA. but, there are none. we had fans and filters to control the flux fumes, which were quite pungent.) in your logic above, chemicals that are far fro similar are being equated and their properties simplified. water and mercury are liquid at room temp. mercury, like lead does not evaporate at soldering temperatures. (for ref: vapor pressure of water at 100C is 760 MM, or 100X the below. try putting 37 C or even 200C in the math below, and I think the answer will be that the vap press is minute and unmeasurable.) _____ http://prola.aps.org/abstract/PR/v26/i6/p851_1 Vapor pressure of lead, 1118° to 1235°C was found to vary from 5.70 mm to 19.70 mm in good agreement with the equation log10p(mm)=-10372/T-log10T-11.35, which also fits the best results of Egerton at lower temperatures. The heat of vaporization of lead at its melting point is calculated to be 46,300 cal. The chemical constant comes out -1.40 which is close to the value -1.59 computed from the quantum theory of monatomic gases. ____ no one I know solders at 1118 degrees c or higher? water has a vapor pressure FAR lower than lead. please realize that the vapor pressure of lead and the vapor pressure of water are NOT close in value. by the above logic, my desk is evaporating. I know ice can evaporate. how do can the the number of formica molecules floating out of the kitchen counter be calculated or measured? here is a bit from wikipedia. Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. Most often the term is used to describe a liquid's tendency to evaporate. It is the tendency of molecules and atoms to escape from a liquid or a solid. At any given temperature, for a particular substance, there is a pressure at which the vapor of that substance is in equilibrium with its liquid or solid forms. This is the equilibrium vapor pressure or saturation vapor pressure of that substance at that temperature. The term vapor pressure is often understood to mean the saturation vapor pressure. A substance with a high vapor pressure at normal temperatures is often referred to as volatile. The higher the vapor pressure of a material at a given temperature, the lower the boiling point. the end. |
What's the story on solder these days?
what about resin lung then ? .......
|
What's the story on solder these days?
There may not have been any EPA guidelines in the past ... but there are
now. I see them every day, all solder stations in our plant haves mandated exhaust facilities - even labs. Particulates are more of a concern rather than vapors. Roger "litle ole me" ""nobody \"@ nowhere.com" wrote in message .. . Prometheus wrote: In article , litle ole me writes except that there is NO LEAD CONTENT IN THE FLUX FUMES. Lead does not vaporize until much higher temperature than soldering temperatures... There will be lead in the fumes; molecules regularly detach themselves and float off into the air from liquids (and can also do so for some solids under certain conditions) at well below the vaporization temperature, perhaps you have not noticed that water at room temperature will evaporate, remember: molten is a liquid. This is why mercury spills are such a problem, and why several years ago laboratories (schools etc.) had to incur expense having floors lifted and mercury removed by special vacuum cleaners, and using mercury vapour detectors to variety 'safe' levels. A few weeks ago I had to clean a spill caused by a broken thermometer from a cupboard. so, what protection should we use when soldering? how much lead would have been ingested? Having worked in a production and engineering environment for many years, I would think that were there any risk of lead in solder fumes, there would be HUGE guidelines from the EPA. but, there are none. we had fans and filters to control the flux fumes, which were quite pungent.) in your logic above, chemicals that are far fro similar are being equated and their properties simplified. water and mercury are liquid at room temp. mercury, like lead does not evaporate at soldering temperatures. (for ref: vapor pressure of water at 100C is 760 MM, or 100X the below. try putting 37 C or even 200C in the math below, and I think the answer will be that the vap press is minute and unmeasurable.) _____ http://prola.aps.org/abstract/PR/v26/i6/p851_1 Vapor pressure of lead, 1118° to 1235°C was found to vary from 5.70 mm to 19.70 mm in good agreement with the equation log10p(mm)=-10372/T-log10T-11.35, which also fits the best results of Egerton at lower temperatures. The heat of vaporization of lead at its melting point is calculated to be 46,300 cal. The chemical constant comes out -1.40 which is close to the value -1.59 computed from the quantum theory of monatomic gases. ____ no one I know solders at 1118 degrees c or higher? water has a vapor pressure FAR lower than lead. please realize that the vapor pressure of lead and the vapor pressure of water are NOT close in value. by the above logic, my desk is evaporating. I know ice can evaporate. how do can the the number of formica molecules floating out of the kitchen counter be calculated or measured? here is a bit from wikipedia. Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. Most often the term is used to describe a liquid's tendency to evaporate. It is the tendency of molecules and atoms to escape from a liquid or a solid. At any given temperature, for a particular substance, there is a pressure at which the vapor of that substance is in equilibrium with its liquid or solid forms. This is the equilibrium vapor pressure or saturation vapor pressure of that substance at that temperature. The term vapor pressure is often understood to mean the saturation vapor pressure. A substance with a high vapor pressure at normal temperatures is often referred to as volatile. The higher the vapor pressure of a material at a given temperature, the lower the boiling point. the end. |
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