saskwche Posted September 1, 2009 Posted September 1, 2009 How can you tell the purity of a solute if let say i was give a bottle of H2O2 and i wasn't sure of the purity of it? Would I have to perform tests to figure out the purity cause i was thinking why not just use molar mass and try and figure out how pure it is, but then i thought to myself what if it has impurities (which is very likely) in it then the measurements would not be precise. So what im asking is if there are tests that i could use that are inexpensive and if so what are they called? My reason for asking is just out of couriosity and I love chemistry so I like expanding my knowledge of it, so in advance thanks to all of those who help me out with my noob questions
Mumbles Posted September 1, 2009 Posted September 1, 2009 I'm not sure how you plan to use molar mass to access purity, nor how you will measure it without a mass spectrometer. The most accurate way would be a titration. A slightly less accurate way would be freezing point depression. There are tables around the interrnet for freezing point vs concentration. Boiling point could be used too, but some would be destroyed in the heating process. You could always add some MnO2, and measure the volume of the gas evolved. Pretty simple HS chem experiment.
saskwche Posted September 1, 2009 Author Posted September 1, 2009 I'm not sure how you plan to use molar mass to access purity, nor how you will measure it without a mass spectrometer. The most accurate way would be a titration. A slightly less accurate way would be freezing point depression. There are tables around the interrnet for freezing point vs concentration. Boiling point could be used too, but some would be destroyed in the heating process. You could always add some MnO2, and measure the volume of the gas evolved. Pretty simple HS chem experiment. In your opinion which would be easiest for a non experienced guy like myself to test the purity?
Mumbles Posted September 1, 2009 Posted September 1, 2009 It's hard to tell, as I don't know how little experience you have. The last suggestion, with the volume of O2 generated, is probably the easiest. Why do you have hydrogen peroxide with a completely unknown concentration, and what are you trying to do with it that it is so critical anyway? There might be an easier way to accomplish what you want to do.
saskwche Posted September 1, 2009 Author Posted September 1, 2009 (edited) It's hard to tell, as I don't know how little experience you have. The last suggestion, with the volume of O2 generated, is probably the easiest. Why do you have hydrogen peroxide with a completely unknown concentration, and what are you trying to do with it that it is so critical anyway? There might be an easier way to accomplish what you want to do. Read my OP and your questions will be answered. I didnt mean with H2O2 i was just using it as an example what if it was lets say it was a acid like 50mls of HCl and i didnt know the purity of it, id have to use a different method to test the purity correct? Another question, how would i go about extracting certain ingredients from lets say a beverage? Ive seen these machines but i forgot the name for them. They spin solutions really fast and separate the solutes in the solution by mass but you dont think it would work with lets say a Coke since the ingredients have been saturated right? Edited September 1, 2009 by saskwche
Swede Posted September 1, 2009 Posted September 1, 2009 (edited) Purity is different from concentration. 30% H2O2 is considered pure if it has nothing except H2O2 and water. If there are sodium or chloride ions floating around, it is not pure. The concentration of something like an acid can be determined by adding known amounts of a base like NaOH and measuring the pH using litmus paper, phenolpthalein, or a good pH meter. Each chemical of interest will probably have a different method to determine the concentration. Another example - if I have an unknown amount of barium nitrate dissolved in water, then I can add an amount of epsom salt (magnesium sulfate) which will knock the barium out of solution as barium sulfate. You collect and weigh the barium sulfate, and from that data, you can derive how much barium nitrate was in the solution to begin with. Determining purity can be harder. Same example, barium nitrate. Let's say it is contaminated with sodium chloride - salt, but we don't know how much. I weigh out a known quantity of the contaminated barium nitrate, say 0.10 moles, and dissolve it. I use the epsom salts to precipitate as much barium sulfate as possible. If I get only 0.098 moles of barium sulfate, then I know that the original barium nitrate had 2% contamination, since the contaminants remains dissolved. This is very simplistic, and to determine the actual contaminants often requires equipment that is very expensive and complicated. All of this is the very basics of chemistry. It all starts with the concept of the mole, and molar masses. Edited September 1, 2009 by Swede
Mumbles Posted September 1, 2009 Posted September 1, 2009 Boooooo, test for sodium contamination with ICP-AES But yes, pretty much every chemical requires it's own unique test. Since you say you're so interested in chemistry, perhaps you should go out and read and learn some of it. It will be far more useful to you than having us try to detail every inane test you can come up with. The instrument you're talking about is probably a centrifuge, although, I wouldn't say it separates stuff by mass quite as well as it condenses all the solid particulates.
Arthur Posted September 1, 2009 Posted September 1, 2009 Go buy yourself a copy of an old guide to qualitative analysis. The VOGEL books Quantitative and Qualitative analysis were old school wet chemistry books on the tests for lots of species. Look in Abebooks dot (your country) Old guides are often better for home chemists as the techniques do not need milti million pound equipment budgets. By far the best guide to purity and concentration is to deal only with suppliers that you can trust. Most aspects of pyro do NOT need great purity, most pyro formulae were invented before the high purity ranges of chemicals existed!
saskwche Posted September 1, 2009 Author Posted September 1, 2009 (edited) Thank you guys a lot. Question about MnO2 Does this need to be purchased through a chemical supplier or can this chem be obtained easily cause i was thinking of trying to make my own battery for the heck of it with MnO2 and Zinc but im not sure what else i would need and if its even safe to make it. Also could i just use MnO2 from dead batteries or would i need to buy or get obtain some from something and to make the battery so it could release energy would i need to add a acid or something as well? By the way im just trying this for the hell of it or would it be a waste of materials? Edited September 1, 2009 by saskwche
flying fish Posted September 2, 2009 Posted September 2, 2009 Read my OP and your questions will be answered. I didnt mean with H2O2 i was just using it as an example what if it was lets say it was a acid like 50mls of HCl and i didnt know the purity of it, id have to use a different method to test the purity correct? Another question, how would i go about extracting certain ingredients from lets say a beverage? Ive seen these machines but i forgot the name for them. They spin solutions really fast and separate the solutes in the solution by mass but you dont think it would work with lets say a Coke since the ingredients have been saturated right? As mumbles pointed out, centrifuges separate suspensions, not solutions. Even some suspensions (nano-scale) might not be separable by centrifuging. Reminds me of something my boss said when we were using a suspension for something..."I'd like that shaken, not centrifuged" I also don't think Coke is "saturated", I think you could certainly dissolve plenty more sugar in there if you tried . The soluability of sugars in water is fairly extreme, actually. Could it be that you are thinking of organic extractions? For instance, you can extract caffeine from beverages with Dichloromethane (a liquid that is not miscible with water). Sometimes they use centrifuges in that case to separate emulsions.
saskwche Posted September 2, 2009 Author Posted September 2, 2009 As mumbles pointed out, centrifuges separate suspensions, not solutions. Even some suspensions (nano-scale) might not be separable by centrifuging. Reminds me of something my boss said when we were using a suspension for something..."I'd like that shaken, not centrifuged" I also don't think Coke is "saturated", I think you could certainly dissolve plenty more sugar in there if you tried . The soluability of sugars in water is fairly extreme, actually. Could it be that you are thinking of organic extractions? For instance, you can extract caffeine from beverages with Dichloromethane (a liquid that is not miscible with water). Sometimes they use centrifuges in that case to separate emulsions. Would it be possible to extract just 1 or 2 things from lets say a energy drink or would it be to hard?
Mumbles Posted September 2, 2009 Posted September 2, 2009 You need to be far more descriptive with your posts. Yes, it is possible to extract 1 or 2 things, but not any 1 or 2 things. For instance, it would be very easy to extract the water from everything else. Since you're beating around the bush, it seems you might be interested in caffeine specifically. Theres nothing else really of interest in them that you can't just buy at the grocery store. Just look at how hard it was to get that information. As you will see, coffee or tea are better sources. http://www.google.com/#hl=en&safe=off&...733483af0cc9d26
saskwche Posted September 2, 2009 Author Posted September 2, 2009 You need to be far more descriptive with your posts. Yes, it is possible to extract 1 or 2 things, but not any 1 or 2 things. For instance, it would be very easy to extract the water from everything else. Since you're beating around the bush, it seems you might be interested in caffeine specifically. Theres nothing else really of interest in them that you can't just buy at the grocery store. Just look at how hard it was to get that information. As you will see, coffee or tea are better sources. http://www.google.com/#hl=en&safe=off&...733483af0cc9d26 Mumbels you got to chill out man haha im just asking questions. Im not really trying to do anything im just asking questions that come to mind. Is it just me or are you becoming irritated with my irrelevant questions lol? If so i can stop but im just trying to learn more since i cant ask what i really want to cause you guys will think im just going to make some explosives are either hurt myself or someone in the process lol. Just to clear up one of the reasons for joining the site was to learn about explosives but since i am not "qualified" or "trusted" yet to know about them im asking BS questions to at least learn others stuff while im here. Also ive seen recipes on how to make high explosives and i dont really want to take the risk of killing myself but i like learning about them and knowing what they do. To some it may sound as a excuse to get my hands on tuts for making some but promise you guys im not ignorant when it comes to explosives. Sure im not completely informed but trust me i dont have the balls or the money to make any. This being said would it be possible to direct me to a link where i could learn about thermobarics or would someone correctly teach me about them. Not asking for tuts on how to make them but how they work.
TheSidewinder Posted September 2, 2009 Posted September 2, 2009 We aren't going to discuss thermobarics here. That's really off-topic, since it fits neither Pyrotechnics nor Chemistry (per se). And to my knowledge it hasn't been discussed in the HE section, either. There's not a whole lot o' chemistry involved with a thermobaric device anyway: Disperse a flammable substance in air, in the right concentration, and then ignite it at JUST the right time after dispersal. Sounds simple. It isn't. That said, we ask that topics and replies be in the right section and SOMEHOW related to Pyrotechnics and/or Chemistry. There's nothing wrong with asking questions, saskwche. It's what you ask, and the way you react to valid information. Ignoring the cautions of those who know better won't score you any points. If you want to learn pyrotechnics, start small and show your results here. Then move up from there.
Mumbles Posted September 2, 2009 Posted September 2, 2009 In case you're unaware how it works, you have to go through me to get HE access anyway. It's based on intelligence, maturity, and responsibility. You're batting around 0 for 3 right now. Annoying me doesn't help your case either.
Ralph Posted September 2, 2009 Posted September 2, 2009 saskwche people arnt keen on answering questions like my permanagenate flash is slow can any one sell me dark flake. but this is a pyrotechnic forum which is free for all to use so long as the folow the guidelines no one is withholding information on how to make explosives if you took a little time to look around you would find hours of reading of the safe preparation perfection testing and using of black powder. I cant speak for mumbles but when he is looking at the posts you have made if you ask "bs questions" that seem to be pointless he isnt about to grant you acsess. also people here arnt your parents or the police they dont really care if you make HE im sure every one would want you to do so safely. also weather you have the "balls" or not you can most certainly afford HE a couple killos of ammonium nitrate costs less than a can of coke
saskwche Posted September 2, 2009 Author Posted September 2, 2009 @thesidewinder Yea i hear where your coming from but im also new to the forum so I havent really checked it out yet(will do now though) so thats why im asking off topic Q's on this thread since i got people attention cause on my older forum youd have to get someones attention to get some decent help and that does not seem like a problem here so ill change my approach on how I research. @mumbles Wasn't specifically asking for access yet but if what i ask falls under that category ill hold of till ive met the requirements. Btw sorry for the irrelevant Q's saskwche people arnt keen on answering questions like my permanagenate flash is slow can any one sell me dark flake. but this is a pyrotechnic forum which is free for all to use so long as the folow the guidelines no one is withholding information on how to make explosives if you took a little time to look around you would find hours of reading of the safe preparation perfection testing and using of black powder. I cant speak for mumbles but when he is looking at the posts you have made if you ask "bs questions" that seem to be pointless he isnt about to grant you acsess. also people here arnt your parents or the police they dont really care if you make HE im sure every one would want you to do so safely. also weather you have the "balls" or not you can most certainly afford HE a couple killos of ammonium nitrate costs less than a can of coke Back to what I told sidewinder im new and dont really know how to use this forum yet but your right so i wont make excuses I know how these forums work so ill start following rules correctly.
Swede Posted September 4, 2009 Posted September 4, 2009 Boooooo, test for sodium contamination with ICP-AES Booo-YOU Mumbles if you have access to one of those:http://www-odp.tamu.edu/publications/tnote...29/technot2.htm I'd love to play with a modern device and see what they do these days. The computerization must be phenominal. Instead of leafing through a gigantic volume of spectra, you probably click a button and do a database search. REAL men don't need computerized mass spec, GC, etc. Saske, we DO have an inherent interest in your activities, not in a bad way. As Ralph mentioned, no one wants anyone to get hurt. But if something bad happened, the first thing they would do is confiscate your computer, and well, there we are. Our goal is display pyrotechnics under an almost rigid safety hierarchy. It is best for all concerned and makes the hobby more legit. Besides, most of us participate for the challenge, and a nice shell is 100X harder than a boomer. Good luck!
saskwche Posted September 4, 2009 Author Posted September 4, 2009 and a nice shell is 100X harder than a boomer. Hell yea it does but I really cant make anything like that around here without the risk of getting caught and as you see I do have things i want to do in my near future so i much stay out of trouble for now. I want to thank you for encouraging me to continue unlike most people around here who call me a terrorist lol.
Miech Posted September 5, 2009 Posted September 5, 2009 Well, there is an easy way to roughly determine the concentration of a H2O2 solution involving an accurate scale and an as accurately determined quantity of H2O2 solution. Given the maximum standard trade solution is about 30% by mass, I wouldn't expect to find a higher concentration. Now, take the H2O2 and acidify it using an overdose of HCl. Then, drop in a chunk of copper, bigger than possibly could be fully dissolve. Try to keep the heat down a bit, it should never get even close to boiling. After any bubbling has stopped, take plastic (!!!) tweezers and take out the remainders of the piece of copper. Now boil down the solution completely (outside or in a fume hood, as HCl fumes will escape the solution) and assure the product is brown (anhydrous) in color. Now weight the final product. Knowing that one mole of H2O2 is consumed for every mole of copper, you can calculate the amount of moles that were in the quantity of H2O2 solution you started with. Some more calculating gives you moles per liter, which then can be converted to mass percent. Yes, it does take some calculations and basic knowledge, but in my opinion you should master this before you get to using stuff like H2O2 for reactions. It's not your best friend after all.
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