| Pages:
1
..
11
12
13
14
15
..
103 |
DraconicAcid
International Hazard
Posts: 4278
Registered: 1-2-2013
Location: The tiniest college campus ever....
Member Is Offline
Mood: Semi-victorious.
|
|
Yes.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
|
|
|
Zyklon-A
International Hazard
Posts: 1547
Registered: 26-11-2013
Member Is Offline
Mood: Fluorine radical
|
|
Flash powder + sulfuric acid--> bang?
I made some KCLO3 and Al flash powder, and put less than half a gram outside, then I added a drop of 98% H2SO4, I
waited about 10 seconds, and then it popped. It was really loud, it reminded me of NI3. The flash powder did not burn at all though, it was
scattered over the ground. Is this a well known fact? Has anyone else done this before?
Edit: Maybe the ClO2 that is formed is exploding?
[Edited on 26-1-2014 by Zyklonb]
|
|
|
Metacelsus
International Hazard
Posts: 2531
Registered: 26-12-2012
Location: Boston, MA
Member Is Offline
Mood: Double, double, toil and trouble
|
|
Chlorates and sulfuric acid explode, especially in the presence of fuels. (The chloric acid formed is VERY reactive.)
|
|
|
Zyklon-A
International Hazard
Posts: 1547
Registered: 26-11-2013
Member Is Offline
Mood: Fluorine radical
|
|
I just took about .25 grams of the same flash, added the drop of sulfuric acid, and proceeded to hit it with a hammer, before it popped by itself.
The boom was massive! My ears are still ringing, it actually wasn't that loud for me, because I was so close, but my mom, in the house said it was
really loud. I also felt the shock wave. I am quite impressed.
|
|
|
alexleyenda
Hazard to Others
Posts: 277
Registered: 17-12-2013
Location: Québec, Canada
Member Is Offline
Mood: Busy studying chemistry at the University
|
|
I've got an Ethanol/Isopropyl alcohol mix, is it possible to isolate ethanol? Their BP is only 3-4 °C different so i'm not sure distillation would be
effective. BTW, I only have a graham condenser.
|
|
|
DraconicAcid
International Hazard
Posts: 4278
Registered: 1-2-2013
Location: The tiniest college campus ever....
Member Is Offline
Mood: Semi-victorious.
|
|
Quote: Originally posted by alexleyenda  | | I've got an Ethanol/Isopropyl alcohol mix, is it possible to isolate ethanol? Their BP is only 3-4 °C different so i'm not sure distillation would be
effective. BTW, I only have a graham condenser. |
Even if they had a twenty degree difference in boiling point, these two liquids are likely to form an ideal solution, and will not separate very well
with distillation.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
|
|
|
alexleyenda
Hazard to Others
Posts: 277
Registered: 17-12-2013
Location: Québec, Canada
Member Is Offline
Mood: Busy studying chemistry at the University
|
|
I see, they probably made it on purpose so it is not possible to distill it. I will use the solution as a solvant then, correct me if i'm wrong but it
should show approximately the same properties as pure ethanol.
|
|
|
Zyklon-A
International Hazard
Posts: 1547
Registered: 26-11-2013
Member Is Offline
Mood: Fluorine radical
|
|
Question:
Why is strontium so cheap? strontium. All the other alkali metals/alkaline earth metals are much more expensive.(except Mg)
Lithium=$150/100g
Sodium=$89/140g
Potassium=$75/5g
Rubidium=$140/1g
Cesium=$140/1g
Beryllium=$15/1g
Magnesium=$3.50/25g
Calcium=$23/50g
Strontium=$85/5lbs
Barium=$140/50g
prices from Gallium Source.com
You have to pay $60 for shipping though
[Edited on 28-1-2014 by Zyklonb]
|
|
|
thebean
Hazard to Others
Posts: 116
Registered: 26-9-2013
Location: Minnesota
Member Is Offline
Mood: Deprotonated
|
|
How can I tell when an organic compound has decomposed in solution? Today I was trying to recrystallize acetaminophen when the solution began to turn
a yellowy/tan color. I've seen this when recrystallizing other organic compounds on occasion, so I began wondering if that was a sign that I was
losing yield.
"You need a little bit of insanity to do great things."
-Henry Rollins
|
|
|
Zyklon-A
International Hazard
Posts: 1547
Registered: 26-11-2013
Member Is Offline
Mood: Fluorine radical
|
|
Question:
I have a sample of a metal wire, I don't know what it is.
It came with my little brothers chemistry set, and for some reason it wasn't labeled.
It's very soft and it felt like solder, but I think it's a pure element. At first I though it was lead or tin, but when I tried to melt it, I found
out otherwise, I could melt it, but the spoon (I melted it in a spoon) was red hot- a lot hotter than necessary to melt lead or tin.
Any quantitative tests I can do?
Edit: Wow I'm dumb, it's zinc, I found two labels in a corner of the pack, one was for iron, the other zinc,I knew my sample Zn immediately,
because, it wasn't magnetic, and I can't melt Iron at all.
[Edited on 30-1-2014 by Zyklonb]
|
|
|
thebean
Hazard to Others
Posts: 116
Registered: 26-9-2013
Location: Minnesota
Member Is Offline
Mood: Deprotonated
|
|
I'm confused by my theoretical yield calculations. I found a piece of literature on the production of diphenylamine via a phosphoric acid catalyzed
reaction between phenol and aniline. I decided that I would carry the reaction out but on a different scale. After my calculations the molar ratio
between aniline and diphenylamine appeared to be 1:2. I was going to used .1 moles of aniline and thus if everything went perfectly, .2 moles of
diphenylamine. Then I looked at the masses of the aniline and diphenylamine. 9.31g of aniline to yield 38.45g of diphenylamine. The ratio of aniline
to phenol is 1:1 so I would be using 9.41g of phenol. This appears to violate the law of conservation of matter, so I was wondering if I was wrong and
if possible where I may have gone wrong.
"You need a little bit of insanity to do great things."
-Henry Rollins
|
|
|
alexleyenda
Hazard to Others
Posts: 277
Registered: 17-12-2013
Location: Québec, Canada
Member Is Offline
Mood: Busy studying chemistry at the University
|
|
Well yes, you are obviously wrong, around 20 g of matter can't be created out of nowhere, as you said, you violate the law of conservation of matter.
Your aniline : diphenylamine 1:2 ratio makes no sense, you double your reagents out of nowhere. To make a simplified equation, (A being aniline, B
phenol and AB the products)
you say : A + B ---> 2AB
while it should be : 2A + 2B --> 2AB
or in fact simply if we divide by 2 everywhere : A + B --> AB.
It is like if you say I will use one TV screen and make two TV out of it :p (yeah I know, the exemple sucks but you get the point). You did not give
enough details about your calculations and did not give your reference, so it is not really possible to help you more than that, but you clearly made
a major error somewhere. The only thing here that is near to a 1:2 ratio is molar mass of aniline : molar mass of diphenylamine, or the ratio amine
group:benzene ring in the product. You may somehow have given the first one, while the second one is quite random :p
One possibility would be that they asked you to use a 2:1 ratio aniline : diphenylamine, in other words to use double the amount aniline so that the
reaction goes faster and somehow you understood it the other way. It is hard to say without your source and your calculations details.
[Edited on 31-1-2014 by alexleyenda]
[Edited on 31-1-2014 by alexleyenda]
|
|
|
thebean
Hazard to Others
Posts: 116
Registered: 26-9-2013
Location: Minnesota
Member Is Offline
Mood: Deprotonated
|
|
You're exactly right! It's a 2:1 
"You need a little bit of insanity to do great things."
-Henry Rollins
|
|
|
Metacelsus
International Hazard
Posts: 2531
Registered: 26-12-2012
Location: Boston, MA
Member Is Offline
Mood: Double, double, toil and trouble
|
|
Sanity check on sulfur analogs
A carbonyl is more electrophilic than a thiocarbonyl, right?
Also, a thiolate is a better leaving group (less basic) than an alkoxide, right?
So, for nucleophilic acyl substitution, which would be a better substrate: an O-ethyl thioester or an S-ethyl thioester? Does the leaving group matter
more than the carbonyl?
RC=S-OEt vs. RC=O-SEt
Does nucleophilic acyl substitution even make sense with thioesters?
[Edited on 1-2-2014 by Cheddite Cheese]
|
|
|
blargish
Hazard to Others
Posts: 166
Registered: 25-9-2013
Location: Canada
Member Is Offline
Mood: Mode Push
|
|
Topic for high school research project?
Hey guys,
I'm doing a chemistry research project at school and I'm having difficulty in finding a topic. My original idea was to synthesize hydrazine sulfate
via the hofmann rearrangement and the hypochlorite - ketazine process, then compare purity with iodimetry. This got rejected because apparently we are
not allowed to be in contact with any substances that may possibly be carcinogenic (hydrazine sulfate). I was wondering if anyone had any interesting
ideas of an area I could explore; not too complicated, but not too simple either. Something that would require a nice experiment and give me good data
to work with. I don't mean to be asking for spoon-feeding here, but any ideas would be appreciated.
BLaRgISH
|
|
|
alexleyenda
Hazard to Others
Posts: 277
Registered: 17-12-2013
Location: Québec, Canada
Member Is Offline
Mood: Busy studying chemistry at the University
|
|
How can I clean bismuth/bismuth oxide from a stainless steel cauldron if it is even possible?
[Edited on 5-2-2014 by alexleyenda]
|
|
|
elementcollector1
International Hazard
Posts: 2684
Registered: 28-12-2011
Location: The Known Universe
Member Is Offline
Mood: Molten
|
|
| Quote: Originally posted by blargish | | I was wondering if anyone had any interesting ideas of an area I could explore; not too complicated, but not too simple either. Something that would
require a nice experiment and give me good data to work with. I don't mean to be asking for spoon-feeding here, but any ideas would be appreciated.
|
Quantitative electrolysis of silver nitrate to form metallic silver?
Titration of NaOH/ HCl?
Thermite, with % yields?
Spitballing here.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
|
|
|
Brain&Force
Hazard to Lanthanides
Posts: 1302
Registered: 13-11-2013
Location: UW-Madison
Member Is Offline
Mood: Incommensurately modulated
|
|
| Quote: Originally posted by blargish | Hey guys,
I'm doing a chemistry research project at school and I'm having difficulty in finding a topic. My original idea was to synthesize hydrazine sulfate
via the hofmann rearrangement and the hypochlorite - ketazine process, then compare purity with iodimetry. This got rejected because apparently we are
not allowed to be in contact with any substances that may possibly be carcinogenic (hydrazine sulfate). I was wondering if anyone had any interesting
ideas of an area I could explore; not too complicated, but not too simple either. Something that would require a nice experiment and give me good data
to work with. I don't mean to be asking for spoon-feeding here, but any ideas would be appreciated. |
Tollen's reagent?
Coordination chemistry of Cr, Co, Ni, Cu?
Rare earth salts fluorescence/magnetism?
Effectiveness of transition metal catalysts in the decomposition of hydrogen peroxide?
pH-mediated fluorescence of pyridine?
At the end of the day, simulating atoms doesn't beat working with the real things...
|
|
|
Zyklon-A
International Hazard
Posts: 1547
Registered: 26-11-2013
Member Is Offline
Mood: Fluorine radical
|
|
I found this Liebig condenser for only $10.00, it is ground glass jointed and 350mm long. Does it look like it will be suitable for laboratory use?
|
|
|
Mailinmypocket
International Hazard
Posts: 1351
Registered: 12-5-2011
Member Is Offline
Mood: No Mood
|
|
Wow, its actually the price for two of them! Doesn't mention the brand or anything though... Sometimes with super cheap glass I have found that the
tapers do not make a good seal, then again...at that price there isn't much to lose!
|
|
|
Zyklon-A
International Hazard
Posts: 1547
Registered: 26-11-2013
Member Is Offline
Mood: Fluorine radical
|
|
Yeah, I saw it said ''Package Quantity 2'', but I wasn't sure what it meant. I think I might get it, that's the cheapest I've ever seen for a Liebig
condenser.
[Edit] Ok, I just ordered it, and it should be here in ~5 days.
[Edited on 7-2-2014 by Zyklonb]
|
|
|
GoldGuy
Harmless
Posts: 45
Registered: 24-11-2013
Location: Toronto, ON
Member Is Offline
Mood: Not sure if awake or in a dream where Im trying to fully awake.
|
|
Anybody know a methylamine synth (preferably from hexamine) in which NO di or trimethylamine is formed?
I saw a synth where the hexamine is reduced by iron/zinc/al or alltogether in the presence of HCl.... The synth didn't specify how much metal to use
so basically my other question is:
Can hexamine be over reduced this type of synth?
[Edited on 7-2-2014 by GoldGuy]
|
|
|
jock88
National Hazard
Posts: 505
Registered: 13-12-2012
Member Is Offline
Mood: No Mood
|
|
I wish to alloy some bismuth with Iron. But bismuth will not dissolve in Iron.
What could you recomment to add to the mix this is similar to bismuth (if it is even sensible to say that) so that I may get a few percent of bismuth
to alloy with the Iron. I am thinking of Antimony?
|
|
|
forgottenpassword
Hazard to Others
Posts: 374
Registered: 12-12-2013
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by GoldGuy | Anybody know a methylamine synth (preferably from hexamine) in which NO di or trimethylamine is formed?
I saw a synth where the hexamine is reduced by iron/zinc/al or alltogether in the presence of HCl.... The synth didn't specify how much metal to use
so basically my other question is:
Can hexamine be over reduced this type of synth?
[Edited on 7-2-2014 by GoldGuy] |
Reduction of nitromethane.
|
|
|
Boron Trioxide
Harmless
Posts: 42
Registered: 18-6-2012
Member Is Offline
Mood: No Mood
|
|
I have a question about divided cell electrolysis, in most descriptions the cell has a semi-permeable membrane and salt bridge presumably to allow the
flow of ions and therefore electric current.
However as a proper semi-permeable membrane is hard to find, would it not be possible to replace the membrane with a specifically chosen non-reactive
metal to allow much greater current to flow, then adding a salt bridge for ion transfer? This would provide much extra current flow, which has always
been a problem for me with only a salt-bridge.
So why would this not work?
|
|
|
| Pages:
1
..
11
12
13
14
15
..
103 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
