How do you purify naphthalene and aniline?
Q. I don't understand these homework problems from my lab on extractions: Suppose you had a mixture of naphthalene and aniline. Propose a procedure to obtain pure naphthalene and aniline samples. The other problem is: Suppose you had a three-component mixture with naphthalene, aniline, and benzoic acid. Propose a procedure to separate this mixture into its three components.
Asked by Thing - Tue Feb 19 02:32:11 2008 - - 1 Answers - 0 Comments
A. Aniline forms an ionic compound with hydrochloric acid (C6H5NH3+ + Cl-) which is soluble in water. Naphtalene isn't, so you can separate the organic phase from the water. Repeat a couple of times, and the aniline will be removed from the organic phase. You can regain the aniline by adding ammonia, so that the aniline will be solvable in a lipophile medium - e.g. ether. Adding benzoic acid to the mix complicates things only slightly. First extract the remaining organic phase with an alkaline solution, e.g. NaOH. Only benzoate will go into the watery phase. You can precipitate the benzoic acid from the watery phase by adding a strong acid. Then continue as above.
Answered by jorganos - Tue Feb 19 04:17:00 2008
Q. I don't understand these homework problems from my lab on extractions: Suppose you had a mixture of naphthalene and aniline. Propose a procedure to obtain pure naphthalene and aniline samples. The other problem is: Suppose you had a three-component mixture with naphthalene, aniline, and benzoic acid. Propose a procedure to separate this mixture into its three components.
Asked by Thing - Tue Feb 19 02:32:11 2008 - - 1 Answers - 0 Comments
A. Aniline forms an ionic compound with hydrochloric acid (C6H5NH3+ + Cl-) which is soluble in water. Naphtalene isn't, so you can separate the organic phase from the water. Repeat a couple of times, and the aniline will be removed from the organic phase. You can regain the aniline by adding ammonia, so that the aniline will be solvable in a lipophile medium - e.g. ether. Adding benzoic acid to the mix complicates things only slightly. First extract the remaining organic phase with an alkaline solution, e.g. NaOH. Only benzoate will go into the watery phase. You can precipitate the benzoic acid from the watery phase by adding a strong acid. Then continue as above.
Answered by jorganos - Tue Feb 19 04:17:00 2008
What masses and percentage of C and H are present in naphthalene?
Q. Naphthalene is a hydrocarbon that is used for mothballs. A 0.3239 gram sample of naphthalene was burned in a C-H combustion train to produce 1.100 grams of carbon dioxide and 0.1809 gram of water. What masses and percentage of C and H are present in naphthalene? C___g C___% H___g H___%
Asked by twilight_fan - Sun Feb 3 11:47:04 2008 - - 1 Answers - 0 Comments
A. Moles CO2 = moles C = 1.100 g / 44.0098 g/mol = 0.02499 Mass C = 0.02499 mol x 12.011 g/mol = 0.3002 g % C = 0.3002 x 100 / 0.3239 = 92.69 Moles water = 0.1809 g / 18.02 g/mol =0.01004 Moles H = 2 x 0.01004 = 0.02008 Mass H = 0.02008 mol x 1.008 g/mol =0.02024 g % H = 0.02024 x 100 / 0.3239 = 6.249
Answered by Dr.A - Sun Feb 3 11:58:01 2008
Q. Naphthalene is a hydrocarbon that is used for mothballs. A 0.3239 gram sample of naphthalene was burned in a C-H combustion train to produce 1.100 grams of carbon dioxide and 0.1809 gram of water. What masses and percentage of C and H are present in naphthalene? C___g C___% H___g H___%
Asked by twilight_fan - Sun Feb 3 11:47:04 2008 - - 1 Answers - 0 Comments
A. Moles CO2 = moles C = 1.100 g / 44.0098 g/mol = 0.02499 Mass C = 0.02499 mol x 12.011 g/mol = 0.3002 g % C = 0.3002 x 100 / 0.3239 = 92.69 Moles water = 0.1809 g / 18.02 g/mol =0.01004 Moles H = 2 x 0.01004 = 0.02008 Mass H = 0.02008 mol x 1.008 g/mol =0.02024 g % H = 0.02024 x 100 / 0.3239 = 6.249
Answered by Dr.A - Sun Feb 3 11:58:01 2008
When you add salicylic acid-naphthalene mixture in a diethyl ether with a saturated aqueous sodium bicarbonate?
Q. When you add salicylic acid-naphthalene mixture in a diethyl ether with a saturated aqueous sodium bicarbonate solution, what kind of gas do they form?
Asked by miss orgo - Wed Oct 15 13:24:04 2008 - - 1 Answers - 0 Comments
A. CO2(g) is evolved... Here's the balanced equation. C6H4(OH)-COOH (salicylic acid) + NaHCO3 (sodium bicarbonate) --> C6H4(OH)-COO-Na+ (sodium salicylate) + CO2 (carbon dioxide) + H2O A wash with aqueous sodium barcarbonate solution is usually done to remove any unreacted acidic reagent (salicylic acid, in this case) from the reaction mixture. As you can see, salicylic acid reacts with sodium bicarb to form sodium salicylate, which is water soluble are therefore goes into the water layer. Meanwhile, the organic layer now only contains naphthalene, which can be recovered by evaporation of the diethyl ether solvent. Hope this helps!!!
Answered by David M - Wed Oct 15 13:30:45 2008
Q. When you add salicylic acid-naphthalene mixture in a diethyl ether with a saturated aqueous sodium bicarbonate solution, what kind of gas do they form?
Asked by miss orgo - Wed Oct 15 13:24:04 2008 - - 1 Answers - 0 Comments
A. CO2(g) is evolved... Here's the balanced equation. C6H4(OH)-COOH (salicylic acid) + NaHCO3 (sodium bicarbonate) --> C6H4(OH)-COO-Na+ (sodium salicylate) + CO2 (carbon dioxide) + H2O A wash with aqueous sodium barcarbonate solution is usually done to remove any unreacted acidic reagent (salicylic acid, in this case) from the reaction mixture. As you can see, salicylic acid reacts with sodium bicarb to form sodium salicylate, which is water soluble are therefore goes into the water layer. Meanwhile, the organic layer now only contains naphthalene, which can be recovered by evaporation of the diethyl ether solvent. Hope this helps!!!
Answered by David M - Wed Oct 15 13:30:45 2008
What is a perfect solvent for naphthalene ?
Q. Is the melting point of naphthalene high or low?
Asked by BEAN - Wed Jul 22 07:44:13 2009 - - 2 Answers - 0 Comments
A. aromatic solvents such as toluene or xylene are probably the best for dissolving other aromatic compounds such as naphthalene, but the usual organic solvents will work as well. These include ethyl acetate, ether, THF, and dichloromethane... the melting point of naphthalene is relatively low at 80.26 degrees C, which is why it is an easy solid to sublime... Hope this helps!!!
Answered by David M - Wed Jul 22 07:55:35 2009
Q. Is the melting point of naphthalene high or low?
Asked by BEAN - Wed Jul 22 07:44:13 2009 - - 2 Answers - 0 Comments
A. aromatic solvents such as toluene or xylene are probably the best for dissolving other aromatic compounds such as naphthalene, but the usual organic solvents will work as well. These include ethyl acetate, ether, THF, and dichloromethane... the melting point of naphthalene is relatively low at 80.26 degrees C, which is why it is an easy solid to sublime... Hope this helps!!!
Answered by David M - Wed Jul 22 07:55:35 2009
What is the solvent and solute of a Naphthalene ball?
Q. Our topic this week is all about Solubility. But, I have a hard time identifying the solute and the solvent of a given solution. I took a quiz about it but our teacher will not tell what's the answer.
Asked by dAiNx - Tue Sep 2 09:36:30 2008 - - 2 Answers - 0 Comments
A. In any solution ; The major component is solvent, The minor component(s) is / are solute(s). In your case, If Napthalene Ball has 95 % Naphthalene + 5 % p-Dichlorobenzene ---> Naphthalene is Solvent ; p-Dichlorobenzene is Solute.
Answered by Real Chemist - Tue Sep 2 10:09:36 2008
Q. Our topic this week is all about Solubility. But, I have a hard time identifying the solute and the solvent of a given solution. I took a quiz about it but our teacher will not tell what's the answer.
Asked by dAiNx - Tue Sep 2 09:36:30 2008 - - 2 Answers - 0 Comments
A. In any solution ; The major component is solvent, The minor component(s) is / are solute(s). In your case, If Napthalene Ball has 95 % Naphthalene + 5 % p-Dichlorobenzene ---> Naphthalene is Solvent ; p-Dichlorobenzene is Solute.
Answered by Real Chemist - Tue Sep 2 10:09:36 2008
How harmful actually is the smell of Naphthalene? What's the best way to get rid of strong smell from the sofa
Q. We have a 9 month old baby and we have just moved into the flat. Not sure yet if the landlady will agree to getting rid of sofa. We really don't know what to do...
Asked by gameT - Fri Jul 4 16:04:54 2008 - - 1 Answers - 0 Comments
A. Best solution is to hire a professional like Coit and have them steam clean your sofa. Hot steam will just about remove everything.
Answered by lightpulse - Fri Jul 4 19:25:01 2008
Q. We have a 9 month old baby and we have just moved into the flat. Not sure yet if the landlady will agree to getting rid of sofa. We really don't know what to do...
Asked by gameT - Fri Jul 4 16:04:54 2008 - - 1 Answers - 0 Comments
A. Best solution is to hire a professional like Coit and have them steam clean your sofa. Hot steam will just about remove everything.
Answered by lightpulse - Fri Jul 4 19:25:01 2008
How can you separate a mixture of salt, naphthalene (mothball ingredient) and charcoal?
Q. The mixture is mixed with water.
Asked by BCT - Tue Aug 11 10:35:22 2009 - - 1 Answers - 0 Comments
A. Substances are purified by different techniques depending on difference in either physical or chemical properties of substances present in the mixture. In your mixture all the three differ in their solubility in water and densities Salt---soluble in water Charcoal --- In soluble and sink to bottom (high density) Naphthalene---In soluble and floats on water (low density) Naphthalene---In soluble and floats on water hence you can remove Charcoal --- In soluble and sink to bottom, separated by means of filtration Salt---soluble in water,if you boil the solution ,water gets evaporates leaving behind the salt
Answered by GRK - Tue Aug 11 11:02:12 2009
Q. The mixture is mixed with water.
Asked by BCT - Tue Aug 11 10:35:22 2009 - - 1 Answers - 0 Comments
A. Substances are purified by different techniques depending on difference in either physical or chemical properties of substances present in the mixture. In your mixture all the three differ in their solubility in water and densities Salt---soluble in water Charcoal --- In soluble and sink to bottom (high density) Naphthalene---In soluble and floats on water (low density) Naphthalene---In soluble and floats on water hence you can remove Charcoal --- In soluble and sink to bottom, separated by means of filtration Salt---soluble in water,if you boil the solution ,water gets evaporates leaving behind the salt
Answered by GRK - Tue Aug 11 11:02:12 2009
Formation of Naphthalene balanced equation and then the combustion equation as well?
Q. Naphthalen (C10H8) is a solid aromatic compound often sold as mothballs. The complete combustion of this substance to yield CO2(g) and H20(l) at 25*C yields 5154 kJ/mol. A)Write a balanced equation for the formation of naphthalene from the elements B)Write a balanced equation for the combustion of naphthalene:
Asked by Stephanie P - Fri Mar 20 13:06:20 2009 - - 1 Answers - 0 Comments
A. 10 C + 4 H2 = C10H8 C10H8 + 12O2 = 10 CO2 + 4 H2O + 5154 kJ
Answered by Dr.A - Fri Mar 20 13:37:39 2009
Q. Naphthalen (C10H8) is a solid aromatic compound often sold as mothballs. The complete combustion of this substance to yield CO2(g) and H20(l) at 25*C yields 5154 kJ/mol. A)Write a balanced equation for the formation of naphthalene from the elements B)Write a balanced equation for the combustion of naphthalene:
Asked by Stephanie P - Fri Mar 20 13:06:20 2009 - - 1 Answers - 0 Comments
A. 10 C + 4 H2 = C10H8 C10H8 + 12O2 = 10 CO2 + 4 H2O + 5154 kJ
Answered by Dr.A - Fri Mar 20 13:37:39 2009
Seperating Naphthalene from Potassium Bromide in a Mixture?
Q. We are seperating components in mixtures using sublimation,extraction,de cantation and filtration. I know sublimation will seperate Napthalene but I dont know after that.
Asked by Trish - Sun Sep 17 20:46:16 2006 - - 3 Answers - 0 Comments
A. Naphthalene is organic, potassium bromide is an inorganic salt. Add an organic solvent (such as diethyl ether) to the mixture. The naphthalene will dissolve in the solvent, the KBr won't. Filter off the KBr, then the solution of diethyl ether will contain the naphthalene. Allow the solvent to evaporate. Presto.
Answered by The ~Muffin~ Man - Sun Sep 17 20:57:55 2006
Q. We are seperating components in mixtures using sublimation,extraction,de cantation and filtration. I know sublimation will seperate Napthalene but I dont know after that.
Asked by Trish - Sun Sep 17 20:46:16 2006 - - 3 Answers - 0 Comments
A. Naphthalene is organic, potassium bromide is an inorganic salt. Add an organic solvent (such as diethyl ether) to the mixture. The naphthalene will dissolve in the solvent, the KBr won't. Filter off the KBr, then the solution of diethyl ether will contain the naphthalene. Allow the solvent to evaporate. Presto.
Answered by The ~Muffin~ Man - Sun Sep 17 20:57:55 2006
Suggest two ways to seperate naphthalene from urea?
Q. Give me a simple way to do that is proven to work, not difficult enough to a degree where i cant understand it. ( I am in AP chem)
Asked by shashank - Wed Aug 22 18:25:08 2007 - - 2 Answers - 0 Comments
A. 1. Recrystallize urea from naphthalene. 2. Sublime naphthalene from urea. 1. Add water to the mixture. Boil. Let cool. Filter the liquid. Naphthalene should crystallize from the cooling liquid. Collect the naphthalene from the filter paper. Evaporate the water to collect the urea. 2. Heat the mixture. Place dry ice (CO2[s]) in a watch glass just above the heated mixture. The naphthalene condenses on the underside of the watch glass. The urea remains behind.
Answered by steve_geo1 - Wed Aug 22 19:03:43 2007
Q. Give me a simple way to do that is proven to work, not difficult enough to a degree where i cant understand it. ( I am in AP chem)
Asked by shashank - Wed Aug 22 18:25:08 2007 - - 2 Answers - 0 Comments
A. 1. Recrystallize urea from naphthalene. 2. Sublime naphthalene from urea. 1. Add water to the mixture. Boil. Let cool. Filter the liquid. Naphthalene should crystallize from the cooling liquid. Collect the naphthalene from the filter paper. Evaporate the water to collect the urea. 2. Heat the mixture. Place dry ice (CO2[s]) in a watch glass just above the heated mixture. The naphthalene condenses on the underside of the watch glass. The urea remains behind.
Answered by steve_geo1 - Wed Aug 22 19:03:43 2007
How long would a 500W heater take to melt 1kg of naphthalene at its melting point?
Q. How long would a 500W heater take to melt 1kg of naphthalene at its melting point?
Asked by scrm92 - Sun Oct 19 08:17:11 2008 - - 1 Answers - 0 Comments
A. Heat of fusion of naphthalene is 148.3 J/g. If the time taken = t sec, then 500 t = 1000*148.3 => t = 148300/500 sec = 297 sec = nearly 5 minutes.
Answered by Madhukar Daftary - Sun Oct 19 08:27:39 2008
Q. How long would a 500W heater take to melt 1kg of naphthalene at its melting point?
Asked by scrm92 - Sun Oct 19 08:17:11 2008 - - 1 Answers - 0 Comments
A. Heat of fusion of naphthalene is 148.3 J/g. If the time taken = t sec, then 500 t = 1000*148.3 => t = 148300/500 sec = 297 sec = nearly 5 minutes.
Answered by Madhukar Daftary - Sun Oct 19 08:27:39 2008
Why is naphthalene insoluble in water, regardless of pH?
Q. I understand why is isn't soluble in water. But why can't it be ionized in aqueous solution?
Asked by l.elam89 - Sat Feb 20 19:30:39 2010 - - 2 Answers - 0 Comments
A. the pKa of hydrocarbons are very high, something like 50 which means you need to have a pH of 50 to have half of the solution ionized. You could ionize it with a super acid, but the super acid won't work in water, it needs to be in a special solvent. The reason is that water will turn into hydronium ion and this has a sort of limit or approximately -5 pH. Hydroxide has a similar limit too, if you try to add a super base.
Answered by Matthew - Sat Feb 20 20:15:12 2010
Q. I understand why is isn't soluble in water. But why can't it be ionized in aqueous solution?
Asked by l.elam89 - Sat Feb 20 19:30:39 2010 - - 2 Answers - 0 Comments
A. the pKa of hydrocarbons are very high, something like 50 which means you need to have a pH of 50 to have half of the solution ionized. You could ionize it with a super acid, but the super acid won't work in water, it needs to be in a special solvent. The reason is that water will turn into hydronium ion and this has a sort of limit or approximately -5 pH. Hydroxide has a similar limit too, if you try to add a super base.
Answered by Matthew - Sat Feb 20 20:15:12 2010
Structure of naphthalene in weakly acidic environment?
Q. How would the structure of Naphthalene and benzoic acid look like in a weakly acidic environment? A weakly basic environment?
Asked by Jamie H - Mon Apr 7 16:29:00 2008 - - 1 Answers - 0 Comments
Q. How would the structure of Naphthalene and benzoic acid look like in a weakly acidic environment? A weakly basic environment?
Asked by Jamie H - Mon Apr 7 16:29:00 2008 - - 1 Answers - 0 Comments
How can I get rid of bats? Is mothballs/naphthalene bad to use in my attic??
Q. How can I get rid of bats? Is mothballs/naphthalene bad to use in my attic??
Asked by ms2715 - Wed Aug 20 12:20:31 2008 - - 2 Answers - 0 Comments
A. Not all bats are protected, as far as preserving your house as habitat, although contacting an interested organization might be useful, Your state should have a department of game and inland fisheries or something like that which might be able to steer you in the right direction. Because they are considered to be environmentally wonderful, but an occasional rabies vector, it would be good to get them to live elsewhere. If you can figure out where they get in and out, just wait until they are gone at night, and screen off their access. sometimes, during the day a one way trap can be placed over the way out, and they can be collected that way. They are extremely delicate creatures, so as recommended above, getting the right help… [cont.]
Answered by character - Wed Aug 20 12:47:30 2008
Q. How can I get rid of bats? Is mothballs/naphthalene bad to use in my attic??
Asked by ms2715 - Wed Aug 20 12:20:31 2008 - - 2 Answers - 0 Comments
A. Not all bats are protected, as far as preserving your house as habitat, although contacting an interested organization might be useful, Your state should have a department of game and inland fisheries or something like that which might be able to steer you in the right direction. Because they are considered to be environmentally wonderful, but an occasional rabies vector, it would be good to get them to live elsewhere. If you can figure out where they get in and out, just wait until they are gone at night, and screen off their access. sometimes, during the day a one way trap can be placed over the way out, and they can be collected that way. They are extremely delicate creatures, so as recommended above, getting the right help… [cont.]
Answered by character - Wed Aug 20 12:47:30 2008
What are the boiling point and freezing point of a 5.18 m solution of naphthalene in benzene?
Q. (The boiling point and freezing point of benzene are 80.1 C and 5.5 C, respectively.)
Asked by KR - Thu Apr 17 20:46:05 2008 - - 1 Answers - 0 Comments
A. kf = 5.12 delta T = 5.12 x 5.18 = 26.5 f.p. = 5.5 - 26.5 = - 21.0 C kb = 2.53 delta T = 2.50 x 5.18 = 12.95 b.p. = 80.1 + 12.95 = 93.05 C
Answered by Dr.A - Fri Apr 18 10:17:10 2008
Q. (The boiling point and freezing point of benzene are 80.1 C and 5.5 C, respectively.)
Asked by KR - Thu Apr 17 20:46:05 2008 - - 1 Answers - 0 Comments
A. kf = 5.12 delta T = 5.12 x 5.18 = 26.5 f.p. = 5.5 - 26.5 = - 21.0 C kb = 2.53 delta T = 2.50 x 5.18 = 12.95 b.p. = 80.1 + 12.95 = 93.05 C
Answered by Dr.A - Fri Apr 18 10:17:10 2008
Is Naphthalene crystals in my ceiling bad for my health?
Q. Can anyone tell me medically the risks of having mass amounts of naphthalene scattered throughout my ceiling, even sitting on exhaust fan covers in kitchen and bathroom. The owner has just done this hoping to deter possoms but now my house stinks of mothballs. Is it toxic to inhale or just ingest. Thankd
Asked by Jasmine - Wed Jul 2 15:14:48 2008 - - 1 Answers - 0 Comments
Q. Can anyone tell me medically the risks of having mass amounts of naphthalene scattered throughout my ceiling, even sitting on exhaust fan covers in kitchen and bathroom. The owner has just done this hoping to deter possoms but now my house stinks of mothballs. Is it toxic to inhale or just ingest. Thankd
Asked by Jasmine - Wed Jul 2 15:14:48 2008 - - 1 Answers - 0 Comments
Naphthalene sublimes easily upon heat. How do I separate a mixture of naphthalene and NaCl?
Q. Naphthalene sublimes easily upon heat. How do I separate a mixture of naphthalene and NaCl?
Asked by hetrp - Tue Sep 12 15:15:21 2006 - - 7 Answers - 0 Comments
A. Naphthalene will sublime easily, Sodium Chloride will not. Heat the mixture of Naphthalene and NaCl causing the Naphthalene to sublime into a gas. Place a cooled surface above the fumes (such as a flask filled with ice water). The cooled surface will cause the Naphthalene vapors to return to the solid phase. Meanwhile, the NaCl will remain in the original container since it will be unaffected by the heating process. This is obviously the anwer your question is going for since it included the fact that Naphthalene sublimes easily and did not mention its solubility at all.
Answered by mrjeffy321 - Tue Sep 12 15:47:54 2006
Q. Naphthalene sublimes easily upon heat. How do I separate a mixture of naphthalene and NaCl?
Asked by hetrp - Tue Sep 12 15:15:21 2006 - - 7 Answers - 0 Comments
A. Naphthalene will sublime easily, Sodium Chloride will not. Heat the mixture of Naphthalene and NaCl causing the Naphthalene to sublime into a gas. Place a cooled surface above the fumes (such as a flask filled with ice water). The cooled surface will cause the Naphthalene vapors to return to the solid phase. Meanwhile, the NaCl will remain in the original container since it will be unaffected by the heating process. This is obviously the anwer your question is going for since it included the fact that Naphthalene sublimes easily and did not mention its solubility at all.
Answered by mrjeffy321 - Tue Sep 12 15:47:54 2006
Naphthalene is a white solid. Does it absorb light in the visible or in the ultraviolet range?
Q. Explain pls.
Asked by oo5ice5oo - Wed Apr 16 11:07:35 2008 - - 1 Answers - 0 Comments
A. It doesnt absorb in the visible range because if it did it would be colorful... if something appears white it means that all colors in the visible spectrum are being reflected (not absorbed). And yes it does have absorbance peaks in the UV spectrum... as described in the link I pasted below.
Answered by Isopropyl_Dog - Wed Apr 16 11:57:41 2008
Q. Explain pls.
Asked by oo5ice5oo - Wed Apr 16 11:07:35 2008 - - 1 Answers - 0 Comments
A. It doesnt absorb in the visible range because if it did it would be colorful... if something appears white it means that all colors in the visible spectrum are being reflected (not absorbed). And yes it does have absorbance peaks in the UV spectrum... as described in the link I pasted below.
Answered by Isopropyl_Dog - Wed Apr 16 11:57:41 2008
How to number groups on Naphthalene?
Q. For instance, 2-Naphthalenecarbaldehyde , why would the CHO group not be labeled as 1?
Asked by Matthew - Fri Feb 26 23:43:48 2010 - - 1 Answers - 0 Comments
A. The numbering isn't quite like it would be in benzene. The numbering of a naphthalene always starts next to the ring junction, and goes systematically around both rings, with the H-bearing C's getting a number first (see The junction carbons are numbered last, but since they never take a substituent in a naphthalene, it's kind of moot. The reason it's done that way is that you want to define where the substituents are relative to that ring junction: if you think about it, simply calling the spot where there's a substituent C-1 would mean you have two possible substituted naphthalenes, both of which would be called 1-naphthanecarbaldehyde (depending on the substituent, of course), and the name would not distinguish between the two… [cont.]
Answered by Steve Watton - Sat Feb 27 10:56:13 2010
Q. For instance, 2-Naphthalenecarbaldehyde , why would the CHO group not be labeled as 1?
Asked by Matthew - Fri Feb 26 23:43:48 2010 - - 1 Answers - 0 Comments
A. The numbering isn't quite like it would be in benzene. The numbering of a naphthalene always starts next to the ring junction, and goes systematically around both rings, with the H-bearing C's getting a number first (see The junction carbons are numbered last, but since they never take a substituent in a naphthalene, it's kind of moot. The reason it's done that way is that you want to define where the substituents are relative to that ring junction: if you think about it, simply calling the spot where there's a substituent C-1 would mean you have two possible substituted naphthalenes, both of which would be called 1-naphthanecarbaldehyde (depending on the substituent, of course), and the name would not distinguish between the two… [cont.]
Answered by Steve Watton - Sat Feb 27 10:56:13 2010
What do you observe upon heating Naphthalene?
Q. is it a physical or a chemical change?
Asked by frigid - Fri Jan 9 06:11:30 2009 - - 2 Answers - 0 Comments
A. That depends strongly on the temperature T and the pressure (which I am ignoring here for the sake of simplicity). If T is below the melting point of naphthalene (80.3 deg C) it is a solid (with a tendency to sublime easily.) If T is above the melting point it is a liquid. The normal boiling point is around 218 deg C. If T keeps rising eventually naphthalene will decompose into smaller hydrocarbon molecules. Further increase of T will generate carbon and hydrogen atoms. At extreme T the atoms involved will become a plasma (an ionized gas). Going from solid to liquid to vapor are all physical processes. Decomposition and plasma formation are chemical processes.
Answered by schillm - Fri Jan 9 06:49:17 2009
Q. is it a physical or a chemical change?
Asked by frigid - Fri Jan 9 06:11:30 2009 - - 2 Answers - 0 Comments
A. That depends strongly on the temperature T and the pressure (which I am ignoring here for the sake of simplicity). If T is below the melting point of naphthalene (80.3 deg C) it is a solid (with a tendency to sublime easily.) If T is above the melting point it is a liquid. The normal boiling point is around 218 deg C. If T keeps rising eventually naphthalene will decompose into smaller hydrocarbon molecules. Further increase of T will generate carbon and hydrogen atoms. At extreme T the atoms involved will become a plasma (an ionized gas). Going from solid to liquid to vapor are all physical processes. Decomposition and plasma formation are chemical processes.
Answered by schillm - Fri Jan 9 06:49:17 2009
From Yahoo Answer Search: 'naphthalene'
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Dispatch Online, South Africa
Empty trash regularly, and keep trash away from the house. l Fix dripping faucets or leaks as cockroaches are attracted to water. l Put naphthalene balls on corners. Roaches hate their smell. l Prevent bugs from coming up the drain. ...
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Mari Kallersjo
Mon, 18 Jan 2010 00:00:00 GM
The insecticides dichlorvos, paradichlorobenzene and . naphthalene. have been commonly used to eradicate pest insects from natural history collections. However, it is not known how these chemicals affect the DNA of the specimens in the ...
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