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Re: Forensics C

Posted: December 4th, 2010, 10:34 pm
by Vizard007
A couple square inches sounds just about right.

Re: Forensics C

Posted: December 22nd, 2010, 4:36 pm
by personasaurus rex
For powders people out there, is there a trick to be able to tell the flame color of certain powders? Because some of them (like the green and the purple) are so faint that half the time you can barely see it. Also, does anyone know why for a lot of the powders that are supposed to burn a certain color they just burn the same orange? It's definitely not the stick burning but it's not supposed to be that color.

Re: Forensics C

Posted: December 22nd, 2010, 5:22 pm
by austinfhs
Sometimes some substances don't burn as readily as they should. Also, you have to consider that what you are burning may not be a pure substance, but mixed with some impure substances. Other reasons could be that you're not positioning the substance within the flame correctly and the flame is not powerful enough. What substance are you having trouble IDing? With enough practice you should be able to identify the flame tests, even though there is not much color coming out. Even though there is no real trick to tell the flame color, so it is more accurate if you use chemical reactions to identify the powder. You can Google some flowcharts that can help you do this, depending on the substance at quest.

Re: Forensics C

Posted: December 22nd, 2010, 5:40 pm
by personasaurus rex
austinfhs wrote:Sometimes some substances don't burn as readily as they should. Also, you have to consider that what you are burning may not be a pure substance, but mixed with some impure substances. Other reasons could be that you're not positioning the substance within the flame correctly and the flame is not powerful enough. What substance are you having trouble IDing? With enough practice you should be able to identify the flame tests, even though there is not much color coming out. Even though there is no real trick to tell the flame color, so it is more accurate if you use chemical reactions to identify the powder. You can Google some flowcharts that can help you do this, depending on the substance at quest.
the worst ones are like potassium chloride, because the color is a faint purple that 1) blends in with the bunsen burner blue and 2) it's so faint that I can never see it. Sometimes boric acid is pretty bad too because the green shows up not regularly.

Re: Forensics C

Posted: December 22nd, 2010, 9:27 pm
by jazzy009
personasaurus rex wrote: the worst ones are like potassium chloride, because the color is a faint purple that 1) blends in with the bunsen burner blue and 2) it's so faint that I can never see it. Sometimes boric acid is pretty bad too because the green shows up not regularly.
I think you may need to be a little more patient with your flame tests; boric acid and potassium chloride are extremely distinguishable! Those, combined with lithium chloride, make for an easy test!

Also (reading earlier posts), all sodiums will burn orange. Not only that, but the sodium stains your loop (what fun!). So if you're getting a constant orange and can tell it's a sodium, you definitely need to clean your loop with acid before running another test with it.

Re: Forensics C

Posted: December 23rd, 2010, 12:02 pm
by personasaurus rex
jazzy009 wrote:
personasaurus rex wrote: the worst ones are like potassium chloride, because the color is a faint purple that 1) blends in with the bunsen burner blue and 2) it's so faint that I can never see it. Sometimes boric acid is pretty bad too because the green shows up not regularly.
I think you may need to be a little more patient with your flame tests; boric acid and potassium chloride are extremely distinguishable! Those, combined with lithium chloride, make for an easy test!

Also (reading earlier posts), all sodiums will burn orange. Not only that, but the sodium stains your loop (what fun!). So if you're getting a constant orange and can tell it's a sodium, you definitely need to clean your loop with acid before running another test with it.
Thank you so much!
and what "loop" are you talking about? o_O

Re: Forensics C

Posted: December 23rd, 2010, 3:13 pm
by austinfhs
personasaurus rex wrote:What "loop" are you talking about? o_O
It's the little wire thing that you use to hold the powder solutions to conduct flame tests.

Re: Forensics C

Posted: December 23rd, 2010, 6:08 pm
by personasaurus rex
austinfhs wrote:
personasaurus rex wrote:What "loop" are you talking about? o_O
It's the little wire thing that you use to hold the powder solutions to conduct flame tests.
oh wow whaaat? we just use wooden splints hahahhahahahaa... could that be affecting our results?

Re: Forensics C

Posted: December 23rd, 2010, 6:12 pm
by austinfhs
personasaurus rex wrote:oh wow whaaat? we just use wooden splints hahahhahahahaa... could that be affecting our results?
Seeing as the wood probably burns ... yes, although a pure metal loop still burns orange. However, your results should be much clearly using the loop because it will burn the powder more than the wood that you have been using.

Re: Forensics C

Posted: December 23rd, 2010, 6:15 pm
by personasaurus rex
austinfhs wrote:
personasaurus rex wrote:oh wow whaaat? we just use wooden splints hahahhahahahaa... could that be affecting our results?
Seeing as the wood probably burns ... yes, although a pure metal loop still burns orange. However, your results should be much clearly using the loop because it will burn the powder more than the wood that you have been using.
oh my... that would eliminate a lot of the problems we're having... thank you so much!! =]