Social Chemistry

My company is giving away a free Ipad for people spending $4000 on an order. What kind of crazy promotions have you seen from your chem company?

Fri, 25 May 2012 18:44 GMT

I work at a company that sells antibodies and they just started a promotion for a free Ipad3 if you spend $4000 on an order. The first thing that popped into my mind is a bunch of grad students or post-docs in a research lab trying to scrounge up enough grant money to buy $4000 worth of reagents from us just so they can fight over who keeps the Ipad...Or a professor trying to come up with an excuse of an experiment to buy that much in reagents just to get the Ipad. What other kind of promotions have you guys seen that are way out there? I find this hilarious.

I posted as a self post so I don't get people thinking I'm actually promoting my company...or karma whoring.

submitted by chocoboi
[link] [3 comments]

High school chemistry EEI

Fri, 25 May 2012 16:56 GMT

I'm doing an EEI on enzymes. I'm using catalase and hydrogen peroxide to produce oxygen. The oxygen is then collected into a measuring cylinder. My three variables are the concentration of catalase, concentration of hydrogen peroxide and the temperature of both. Increasing the concentration of catalase is supposed to speed up the reaction, which it has, but it is meant to decrease the time of the reaction, which it also has. I have calculated the theoretical yield and our actual yield is really close. My question is, how do you calculate the theoretical time the reaction should occur for. I asked my teacher if there is a way to do it and he said that there is however it is beyond a highschool kid. I get A+'s in chemistry and top the class, so I would really like to impress him by being able to calculate the theoretical time of each reaction.
Catalase concentrations are 5%, 10%.....30% with 1% hydrogen peroxide, both kept at 40°C.

Thanks for your help

Best way to wash a lab coat?

Fri, 25 May 2012 14:41 GMT

I'm not sure if putting it in the washer would be a wise idea.

submitted by salvamag
[link] [6 comments]

Sorry if this is the wrong place, but I figured someone here could answer this. Would rain-x ruin sunglasses?

Fri, 25 May 2012 14:06 GMT

I don’t know why it would, but I’d hate to ruin my sunglasses by doing something that I’m unsure of.

EDIT: The sunglasses are polarized if that makes a difference.

submitted by ISS5731
[link] [3 comments]

chloroform

Fri, 25 May 2012 11:29 GMT

Why is not chlorofom a base?Cl could make a bond with hydrogen through free electron pair,or not?
Thanks

how separate these substances from each other?

Fri, 25 May 2012 10:59 GMT

I like to play with chemistry and wondering if anyone here can help me a bit.
I possess a mixture containing
fatty alcohol ethoxylate CAS No. 68439-45-2. 5-10%
gamma butyrolactone cas No. 96-48-0 60-100%
glycol ether CAS No. 005131-66-8 10-30%
orange terpenes CAS No. 8028-48-6 1-5%

Someone here who knows how I can achieve this? I possess in general a reflux distillation with a column like this http://www.ebay.com/itm/New-24-40-Reflux-Condenser-/370611122106?pt=LH_DefaultDomain_0&hash=item564a24efba#ht_919wt_1110 can distinguish the different substances from each other whith this? or someone who has some good advice? someone who does not know but who still know where I can dedicate my knowledge, do not hesitate to answer

thanks for answers

MOVED: Question regarding 'molar feed ratio' for atom transfer radical polymerization

Fri, 25 May 2012 06:43 GMT

This topic has been moved to Materials Chemistry forum.

http://www.chemicalforums.com/index.php?topic=59289.0

Question regarding 'molar feed ratio' for atom transfer radical polymerization

Fri, 25 May 2012 06:34 GMT

I am trying to emulate a coating process for a 316L stainless steel substrate. One of the steps calls for the atom transfer radical polymerization of poly(ethylene glycol) methacrylate. I have a pretty clear understanding of all the other steps involved but I am a bit unclear with one step.

"Surface initiated atom-transfer radical polymerization of PEGMA should be carried out using a [PEGMA (4mL)]:[CuBr]:[CuBr2]:[2,2’-bipyridine] molar feed ratio of [100]:[1]:[0.2]:[2] in 4 mL of N,N’-dimethylformamide"

I interpreted the molar feed ratio to mean mix the above substances in DMF at a ratio of [100 mol]:[1 mol]:[0.2 mol]:[2 mol] or an equivalent ratio, but I just want to make sure I'm not over simplifying it.
any help would be greatly appreciated

Δ[C]/Δt

Fri, 25 May 2012 05:27 GMT

In the reaction:
A+2B 2C
the starting concentration of substances A and B are 0.3mol/dm³ and 0.5mol/dm³. The speed constant of the reaction is 0.4dm⁶/mol²s. Calculate Δ [C]/Δt:
a)at the beginning of the reaction
b)after some time, when the concentration of substance A reduces by 0.1mol/dm³.

The problem is that I don't have the answer so I need someone to check my thoughts:
a)V=k[A][ B]²=Δ [C]/Δt*1/2
Δ [C]/Δt=0.06mol/dm³s
b)Same equation. but the concentrations of A and B are 0.2mol/dm³ and 0.3mol/dm³
Δ [C]/Δt=0.0072mol/dm³s
Correct?

Reaction between phosphorous and nitrogen?

Fri, 25 May 2012 02:36 GMT

I really do not know, but I do not think that elemental phosphorous readily reacts nitrogen directly. There seems to be very little information about this available.

"phosphorous nitride, P3N5
White, odorless, tasteless; decomposes into its elements in vacuum at high temperature. Insoluble in all solvents. Heating with water in a sealed tube to 180 °C decomposes P3N5, forming H3PO4 and NH3. Oxygen affects it (ignition) only at temperatures above 600 °C."
Handbook of Preparative Inorganic Chemistry 2nd ed

Another source described "another form of phosphorous nitride sublimes" towards 1000 °C. The heat of formation of P3N5 was experimentally calculated at "70.4 cals" (-43.9 kcal/mol ?).

"Above 800 °C, P3N5 decomposes, evolving nitrogen: P3N5 --> 3 PN + N2
Phosphorous(III) nitride, PΞN, ... is metastable with respect to decomposition into P2 and N2, PN --> 1/2 P2 + 1/2 N2; Δ= -98 kJ ), but at low temperatures it polymerises into a coloroless phosphorous(III) nitride. In addition to the above compounds, there are intractable yellow to brown nitrides with high melting points and stoiciometries that lie somewhere between PN and P3N5.
"Inorganic Chemistry", Egon Wiberg, A. F. Holleman, Nils Wiberg, p737

None of the sources I have found make any mention to direct reaction between P4 and N2.

"Thus phosphorus nitride is formed comparatively readily only when nitrogen interacts with atomic phosphorus..."
The literature data on the methods of preparation, structures, and properties of phosphorus nitrides PN, poly(phosphorus nitrides) (PN), (P3N5), ... are surveyed and their practical applications, formed as a result of the direct binding of molecular nitrogen... are examined.
"Phosphorus Nitrides", Evgenii V Borisov and E E Nifant'ev

I suppose the ideal experiment would bring vaporised P4 at a high temperature in contact with nitrogen gas, then see if any PN polymer formed as a powder. Simply trying to heat solid phosphorous with nitrogen would not work, because the nitride would potentially form a protective coating, with a high decomposition temperature, that would inhibit further reaction.

Atmospheric pollution

Fri, 25 May 2012 01:54 GMT

Which is correct
(1) Photochemical smog is oxidizing in character and is formed during winter
(2) Winter smoke is reducing in character due to absence of SO2 and carbon particles
(3) Particulates of size about 2-3 microns can enter lungs directly
(4) Prop-2-ene-1-al on oxidation with O3, NO2 forms PAN

elimination, substitution and addition reaction

Thu, 24 May 2012 22:32 GMT

The reaction in below hyperlink
hxxp://imgur.com/ooKI6

I and II represent

(1) Substitution, elimination
(2) Elimination, substitution
(3) Substitution, addition
(4) Addition, elimination

Explain Why?

Elimination, Substitution or addition reaction

Thu, 24 May 2012 22:26 GMT

Any GPC users out there?

Thu, 24 May 2012 21:57 GMT

So I'm recently graduated (last December) and have a job at a plastics factory as a lab chemist. As you could imagine, we have a GPC. Since I haven't had any exposure to anything GPC related, I was wondering if anyone with experience could offer a few tips or pointers they found useful in their dealings. We actually have two GPCs, one that runs at ambient temp, and another at high temp (150 C). The ambient uses THF, and we currently have TCB running through the high temp, but are currently looking at other solvents that are not UV active, as we would like to be able to use the UV detector on the high temp.

I realize GPC had a falling out, one might say, in the analysis world and that not many may work with it, but from what my boss and others have told me, it is making a comeback.

Thanks

submitted by fecallube
[link] [4 comments]

Gas Laws Diagram

Thu, 24 May 2012 21:25 GMT

Hi, I was studying the gas laws over my sophomore year of high school for my Chem I class and I came upon this idea for a new diagram
displaying the three gas variables and their relations. Can someone please tell me if my diagram I made is correct or incorrect?
Thanks in advance,
Alex
hxxp://www.flickr.com/photos/79361773@N08/?uploaded=1&gic_cookie=bda52fdf9f87b5982df1de146d0fa147

{MOD Edit} break link, attach image

Crystals that reformed after I had washed my product out of a round bottom flask with solvents

Thu, 24 May 2012 21:17 GMT

submitted by Zodiathan
[link] [15 comments]

Temperature conversion Formula

Thu, 24 May 2012 20:57 GMT

Formula for changing ferenheit to celcius C=degree in celcius F=degree in ferenheit

F=C•1.8+ 32 C=F-32divided by 1.8

Formula for turning Kelvin into celcius and celcius into Kelvin K=Kelvin C=celcius

C=K-273.15 K=C+273.15

Formula for changing celcius into Rankine abs Rankine into celcius

C=R-491 divided by1.8 R=C•1.8+491

The • means multiply

submitted by argonfluorohydride
[link] [3 comments]

Thallium and Aluminum oxidation states

Thu, 24 May 2012 19:05 GMT

How come aluminum's oxidation number is +3 and thallium's (stable) oxidation number is +1, and they both are in group 3A? It seems like thallium should have the higher oxidation state because it's bigger than aluminum, so wouldn't it be easier to ionize?