Chemistry's topics - tribe.net

Esterification of Vanillin In Presence of Acid

2008-07-23T08:01:13Z

Not sure what happens here when vanillin reacts with acetic anhydride n the presence of an acid...

The NMR of the acid product shows peaks at - ppm (integration) -
2.1 (6.37)
2.3 (2.90)
3.8 (3.00)
7.1 (3.22)
7.6 (1.08)

im really bad at NMRs... so im not getting too far with this..

thanks!

posted in Chemistry - 5 replies

Marketing at it's finest!

2008-07-03T23:55:48Z

Too much!

http://www.eppendorf.com/int/hawkpopup.php?contentid=13

posted in Chemistry - 1 reply

Vanillin and Acetic Anhydride

2008-05-09T22:36:32Z

Figured out the products and mechanism under basic conditions but still haven't figured out what happens with base! I have a mass spec of that product and its showing it formula mass to be around 255. Anyone know what happens or what it is?

posted in Chemistry - 3 replies

Question...How do I determine the % of alkaloids in a plant.

2008-04-19T10:53:30Z

I figure that if I put a set amount of plant material in a soxhlet with the right solvent and do a very complete extractions. I will do many triels with the same plant material. I will dehydrate them all and weigh them with a good miligram scale. I will also do a series of them except I will defat the plant material first. I want to compare the amount of yield from different batched of the same plant. Any suggestions as to a better way to do this? Please help me out.

posted in Chemistry - 3 replies

Medicinal Chemistry positions?

2008-04-11T20:06:58Z

Does anyone know of medicinal chemistry (drug discovery) openings in the SF Bay Area? I prefer working with small or start-up companies. Please PM if you have any leads.

Thank you,
Troy

posted in Chemistry - 2 replies

I'm looking for a chemical engineer... Know any?

2008-04-10T13:44:28Z

Hello chem tribesters! :D

I'm a graphic design student, taking a class in sustainable design, and I have a question or two that would probably be best answered by someone with a background in chemical engineering. Know any that I might be able to email?

thanks!

talia

posted in Chemistry - 1 reply

Pchem..

2008-03-08T17:09:22Z

or whatever you want to call it. Its about to start. I dont know what to expect other than derivatives, and lots of math. Maybe none of you could help me with what to expect as each school seems to have a different version of this class. But I would like to hear stories of your Pchem class as it seems to be the character revealing class for chem people.

Stories?...

posted in Chemistry - 25 replies

HPLC question

2008-02-24T18:24:38Z

How much of a sample or "standard" of the pure substance I am testing for do I need so that I can identify peaks for an HPLC test?

posted in Chemistry - 1 reply

Is this entirely true? The "two sticks of dynamite" portion is that about which I am wondering....

2007-11-05T01:09:27Z

The note and link below were forwarded to me.

========================================================

This is a very dramatic and short 30-second clip shows how to properly and improperly deal with a common kitchen fire: oil aflame in a pan.

“At firefighting training school they would demonstrate this with a deep fat fryer out on the fire field. An instructor in a fire suit and using an 8 oz cup at the end of a 10 foot pole would toss water onto the grease fire. The water, being heavier than the oil, sinks to the bottom where it
instantly becomes superheated. The explosive force of the steam blows the burning oil up and out. On the open field, it became a thirty foot high fireball that resembled a nuclear blast. Inside the confines of a kitchen, the fire ball hits the ceiling and fills the entire room.

Also, do not throw sugar or flour on a grease fire. One cup creates the explosive force of two sticks of dynamite.”

http://www.ranaldofamily.com/SWF/KitchenOilFire.wmv

========================================================

I checked at Snopes.com to see if this tidbit is rated "partially true," as I expect, but did not find it listed.

If the writer is talking about a cup of flour aerosolized and ignited while suspended in the air, as with lycopodium powder, then I can at least see where s/he might be led to think a cup of flour has the explosive force bound in two sticks of dynamite -certainly an entire cup of fine particles from just about any flammable material would make a dangerously large flash and bang if ignited while suspended in air. But would the resultant explosive force actually be equivalent to that liberated from two sticks of dynamite? I wonder. Likewise, while sugar does have a relatively large amount of chemical energy bound in the molecule, would simply tossing a cup of sugar into a pan of flaming oil release two dynamite sticks' worth of explosive force? This seems unlikely. Alfred Nobel would have made his fortune that way rather than with TNT if so, it would seem.

My heart goes out to the gal who discovered the part about water and flaming oil the hard way.

Any comments on the "two sticks of dynamite" portion?

posted in Chemistry - 1 reply

New Tribe: GLBT Scientists,Techs, & SciStudents

2007-10-20T01:06:57Z

Announcing a social networking forum on Tribe for GLBT scientists.

http://tribes.tribe.net/glbtscientists

This tribe is a social networking forum for Gay, Lesbian, Bi, Trans, Intersex, Queer, and friendly heterosexual Allies in the sciences and technical professions (including allied medical fields). Discussion of topics directly related to the science of same-sex attraction is welcome, as is inviting discussion regarding career considerations for GLBTIQA folks in the sciences, questions and requests for assistance related to queer science topics, posting of queer science humor, and--of course--flirting. What would a social networking group for GLBTIQA scientists, techs, science educators, and science students be without humor and flirting? Anyone and everyone who joins this tribe is also highly encouraged to become an official member of NOGLSTP, the National Organization of Gay & Lesbian Scientists and Technical Professionals (www.noglstp.org) -you will be glad you did!

posted in Chemistry - 0 replies

mathCad

2007-09-28T03:13:11Z

i'm fairly sure that mathCad will cause the demise of my hopeful chem major.
that damn thing is constantly crashing, and somehow, it seems to KNOW when i'm about to save. or when i've just figured out how to replicate a complicated formula.

whiz! bang! beep....beep....beep.

do you want to send an error report?

silly contraption.

posted in Chemistry - 5 replies

O... Chem! Advice for a newby?

2007-09-21T05:41:53Z

O-Chem has just kicked off at a brisk pace- my prof is operating under the assumption that we have solid chemistry backgrounds and has launched in full force. Unfortunately, I took my gen chems elsewhere in a really intense/ abbreviated format and I seem to be a tad behind on the knowledge others have brought it.

Can anyone provide a list of concepts to review or teach myself to really be prepared for whats to come and is already rapidly unfolding? Any advice on study techniques are also welcome... It looks like this will seriously involve a ton of drawing and memorizing... correct?

posted in Chemistry - 15 replies

random biochem question

2007-09-04T01:21:37Z

hey all,
was wondering if anyone knew of a good website that shows exactly what angles psi and phi are in an amino acid chain. my biochem book is kind of confusing because it's hard to tell which plane they are saying these two angle are in, which direction, etc (not to mention it's kind of hard to explain).

thanks much!

posted in Chemistry - 0 replies

deindrimers

2007-08-02T20:00:42Z

hey all,
just got an email about this new product from a company in australia that has completed phase one trials. the article from the american chemical society is very interesting and all encompassing since these molecules (dendrimers) are being developed for use elsewhere in medicine. i also received two other articles from other sources following the acs link. any thoughts on these?

take care,
ben

http://pubs.acs.org/cen/coverstory/83/8324dendrimers.html

http://news.yahoo.com/s/po/20070731/co_po/microbicidallubereportedtoblockhiv

http://money.cnn.com/news/newsfeeds/articles/prnewswire/LNTU00424072007-1.htm

posted in Chemistry - 0 replies

Mercury Thermometers?

2007-07-24T23:36:58Z

Hi all!
I need mercury thermometers (Specifically ASTM 11C and 3C), but nobody will ship them to CA anymore... Does anyone know of an in-state supplier?

posted in Chemistry - 1 reply

Biochemistry examples

2007-06-22T00:56:01Z

OK. We're exploring protein separation techniques. The Prof is not always clear on what he wants. Hes said that we do not need to know the amino acids, but then three days later on the test we are asked which amino acids will be on a protein on the inside of a plasma membrane, outside the cell, and inside the cell. Also we were asked what roles each of the amino's played in general. like histidine is a positive polar, and the like. So Im a little edgy when trying to decipher what he wants. But I don't have time to just memorize everything, and all things biochemical. So, this brings me to my quiz tomorrow. Hes asked us to read about working with proteins, and study up on chromatography, electrophoresis, and activity of the proteins.
Im guessing what he would ask us to do and Ive come up with a potential Q. Could you please come up with an answer?

Q. How would you separate out a medium sized(500dalton) protein with a charge of [ -.97] in pH 6.4. out of a mixture?

Or would a better question be

Q.How would you determine the size, and charge of a protein?

AM I right in thinking that size, charge, and active sites are the only things you can separate proteins by?

posted in Chemistry - 12 replies

To be a chemistry highschool teacher.

2007-04-08T09:34:14Z

education is one of those things that people will pin you to the wall to talk about. At least those that have wrestling training do.

But what I wanted to ask was: In being a teacher, what should my tactics be? Strategy? how should my examples flow? WHAT DO I DO?
In a little bit I'll restate my questions, but I hope for some answers now so I can construct those real questions.

posted in Chemistry - 7 replies

To where I have never gone before...

2007-04-04T06:49:24Z

Biochem starts monday here at EWU(pronounced Ewwwwwww.) and im not wooried, but thats mostly because I havent heard anyone wax edgar allen poe about it. Nor for that matter HP lovecraft about it(the fungi of yuggoth removed the skin from the poor biochem student and replaced it with wings made of Velveeta cheese). Im not sure what the intention of biochem is. could someone enlighten a good little Ochem student(who is all about the electron density, claisen condensation and bromination)?

posted in Chemistry - 4 replies

wanted: freeware chart application

2007-03-09T17:42:25Z

Howdy folks

I'm looking for an easy-to-use, decent quality freeware application that can generate clean graphic files. It would be extremely helpful for my work. I currently spoof charts in Illustrator, but there has to be a better way - something that's chart/graph specific.

I'd like to generate output not unlike these graphs:
http://wings.buffalo.edu/aru/ARUappendC.htm

Any ideas?

Thanks!

Barnaby

posted in Chemistry - 1 reply

Further adventures

2007-02-06T06:16:43Z

Ok so here I am week three into 1st qtr of Ochem. Trying to remember all the constituents of a lewis base and acid. Keeping in mind all the conformers, cis and trans. Just getting into basic organic reaxctions like addition, subtraction, elimination. Ive just been told that this is the easy part. Well thats good to hear. Ive been waiting for the other boot to drop for weeks now. I was told that Ochem was VERY hard, and so far it hasnt been. Its been a cake walk. There hasnt been a single thing I havent been able to do within 10 minutes. Is the supposition that its going to get harder in the next few weeks for real? or is this another boot suspended in midair forever?

posted in Chemistry - 29 replies

Call For Makers!

2007-02-02T20:47:31Z

We are pleased to announce Bay Area Maker Faire 2007!

Organized by the staff of MAKE and CRAFT magazines, Maker Faire is a newfangled fair that brings together science, art, craft an engineering in a fun, energized, and exciting public forum. The aim is to inspire people of all ages to roll up their sleeves and become makers. This family-friendly event showcases the amazing work of all kinds of makers--anyone who is embracing DIY and wants to share their accomplishments with an appreciative audience. Last year, we had 20,000 people at Maker Faire.

Maker Faire Bay Area will take place May 19-20, 2007 at the San Mateo Fairgrounds. We are also adding Maker Faire Austin for October 20-21, 2007 at the Travis County Fairgrounds. This call is primarily for Maker Faire Bay Area but you can indicate if you are interested in participating in Maker Faire Austin.

We encourage you to join the fun and propose a maker exhibit, performance or workshop. You can submit a proposal through the web using the link described below or you can come show us your work at a Maker Faire "audition" on Saturday, February 24 at TechShop in Menlo Park, CA.

http://www.makerfaire.com

Proposals: We invite proposals for Maker workbench exhibits, workshops, presentations and performances for the Maker Faire. We are interested in proposals from individuals as well as from groups such as hobbyist clubs and schools.

Maker Workbench: Our standard setup for Makers is a six-foot long workbench. You can use this workbench to display your work and/or demonstrate how you make something. Some makers don't need workbenches, typically because they have a large object or they set up outside. Please provide a short description of what you make and what you will bring to Maker Faire. Please link to photographs or videos of what you make. Let us know about any requirements you have, such as electricity, Internet, ventilation, etc.

Interactive Performance: We're seeking performances that will engage and entertain the attendees and enable them to interact in a fun way. The performances may be tied to a stage or roving through the fairgrounds as a kind of street theatre. Performances could be musical or theatrical, but they could also be a collaborative building process. For example, you might work with attendees to put something large together in an hour.

Presentation: These includes audio-visual presentations intended for showing a project (or process) that cannot be brought to the faire, or a special project that requires AV resources. These presentations are limited to 20 minutes. Please describe the topic of your presentation and what kind of media (audio/video) that you will have. As a general rule, PowerPoint presentations are not appropriate for this event unless they are unusually entertaining.

Demonstration Workshop: A demonstration workshop is a show-and-tell session on how to make something. We're looking for makers who can demonstrate (and teach) particular skills, techniques or processes. You should start off by explaining your materials and tools and then step-through a build process, sharing your knowledge and interacting with the audience. Sessions should be under 30 minutes in length and may be repeated on the program. Please describe the subject of your workshop and what kind of setup you need for it.

Application Form: Please go to the following URL and fill it out to apply for participation as a maker. http://makerfaire.com/bayarea/2007/proposal/

All proposals will be reviewed and we will notify makers of acceptance via email by March 19, 2007.

NOTE: Presenters whose talks are accepted will receive free registration to Maker Faire. We cannot pay for travel and accommodations. (We do make exceptions under some circumstances.) If you have any questions about participating in Maker Faire, please contact Natalie Villalobos by email: info@makerfaire.com. Please let Natalie know if you plan to come to the audition at TechShop.

Key Points:

* Maker Proposal Due: Midnight (PST): Feb. 27, 2007

* Maker Faire Bay Area Audition: Saturday Feb. 24, 2007

* Notification of Acceptance: March 19, 2006

* Confirmation of Participation: April 2, 2007

* Maker Faire Bay Area: May 19-20, 2007; Saturday 10-6 pm; Sunday 10-5pm.

* Maker Faire Austin: October 20 .. 21, 2007

* Application Form: http://makerfaire.com/bayarea/2007/proposal/

Commercial Exhibitors If you are a commercial maker or you work for a company that would like to exhibit at Maker Faire, please contact Sherry Huss sherry@oreilly.com.

posted in Chemistry - 0 replies

chemistry blog, definitely worth reading

2007-01-23T02:49:48Z

this is from a student of Barry Trost's at Stanford.

http://blog.tenderbutton.com/

he recently stopped writing to focus on other things but it will be archived...

posted in Chemistry - 1 reply

water & ice

2007-01-14T16:13:36Z

This is something that has puzzled me for quite some time: why is solid water (ice) less dense than liquid water? Any idea?

Kevin

posted in Chemistry - 14 replies

Redox Schmedox

2007-01-06T02:55:22Z

Okay, I'm trying to figure out the order in which redox reactions would take place in an open flame environment for a specific compound.

Specifically, i need to know which atom is most likely to get affected first in open burning of ethyl acetate. I'm concerned that a burn by-product might be acetone, and I've heard bad things about open acetone burning.

any help is greatly appreciated...

posted in Chemistry - 2 replies

Vit. D lab question

2006-12-27T20:52:56Z

I posted this in the Biochem tribe, but no one answered, so I thought I would give it a shot here before I start making long-distance phone calls.

Is anyone familiar with the tests required to determine circulating 25(OH)D levels to determine someone's vitamin D nutritional status? Price, how long the results take, what labs to use, etc?

Thanks,
Grandma

posted in Chemistry - 4 replies

Gearing up for Organic chem, 1st in the series.

2006-12-23T18:26:42Z

So I have decided to start memorizing the functional groups. what a ketone is, what a alkyne is...

My question is, What else should I do? I will have limited time to study, So Id like to have a prioritized study schedule. What is most important, and what should I study now while I have a month before class starts.

posted in Chemistry - 16 replies

Serious question about analytical instruments

2006-11-23T20:30:12Z

Can anyone recommend a good vendor(s) for some analytical instruments?

I need a conductivity probe, 0 to 2000 uS/cm
thermocouples, -5 to 35 C
and a flow meter that can measure as low as 20 ml/min but can be scaled up.
They all have to communicate with some type of Data Module with a USB port.

Not a joke. I need them for a project and I haven't done this sort of thing in years.
I am going crazy sifting thru vendor webpages and am looking for some shortcuts.

Dave

posted in Chemistry - 1 reply

Newbie looking for guidance

2006-11-15T20:36:49Z

I'm new to Chemistry practices and in the process of trying to put together a small lab. Is there someone in the Seattle area who would be willing to guide me along personally?

posted in Chemistry - 0 replies

torn...

2006-11-15T00:07:04Z

So Im taking quantitativ analysis, and ochem 353. On one side I remember that chemistry is supposed to be fun, intense, and imagination inspiring. on the other I remember that it is a hard science and that math is a backbone, or at least a pelvis(mixing metaphors?) and that I should be rigorous with my education. But it seems that two such different classes could exist within the same field. quant is pretty much pure numbers, while ochem is pure beauty. I was talking with Venkatasen about fischer projections of sugars, and mutarotation under basic rections, in particular with fructose, and wondering where in the chemistry of cooking I could promote mutarotation of sugars with an ingredient that was edible. The discussion was all about chemistry and its practical applications, and the possibility of making one sugar into another sugar by some age old method. I like talking about real chemistry(real in the sense that even normal people have a desire for it) an example would be transforming the basic amines of stinky fish into a heavenly aroma using orange juice to neutralize the amines. Or using the natural monosodium glutamates that occur in tomatos to make things taste better. Or even the simpleNaCl and vinegar that makes small quantities of HCl insitu.
The torn part come in the quant class where its lots of ph, log, [x], [x]^2, E=Ecell-.05916/n * ln(q), etc..... Im SURE there are chem folks who find teh beauty in the ln(q), whereas I find the beauty in the synthesis of a micheal rxn, or of methylation of an organic. Butu personally in the sense of what I will try to take and respect and acknowledge as being the most important part of chemistry, well, Im torn...

or maybe Iv just had one too many belgian beers and Im waxing poetic about Ochem. hm.

posted in Chemistry - 6 replies

wanted: newbie resources

2006-10-16T04:28:26Z

Hi folks

I'm looking for web-based tutorials etc that can introduce me to the basics of chemistry and chemical reactions. One thing that I'd really like, for example, is to have a better understanding of the naming conventions of chemicals. Any resources you can direct me towards would be greatly appreciated.

Bio- or organic chemistry resources would be best of all, as I'm starting to look at pharmacology.

Many thanks!
Barnaby

posted in Chemistry - 6 replies

Oh haha!

2006-09-06T14:52:51Z

If you're not part of the solution, you're part of the precipitate.
- Henry J. Tillman

A Chemical is a Substance that:

An organic chemist turns into a foul odor.
An analytical chemist turns into a procedure.
A physical chemist turns into a straight line.
A biochemist turns into a helix.
A chemical engineer turns into a profit.

posted in Chemistry - 7 replies

APchem

2006-07-30T17:24:48Z

Did anyone take the advanced placement chemistry exam in high school?
Did you pass?

I thought it was rather difficult.
The first year my high school had an ap chem class one person got a five, one person got a four, and the rest didn't pass. I don't know how this last year (my senior year) did, but I certainly didn't do very well (or pass ><).

posted in Chemistry - 4 replies

DEEEP into Ochem Lab...

2006-07-13T04:29:30Z

So Im taking Ochem 2nd qtr, and Ochem lab this qtr, and not really regretting it, buut I wish I hadnt taken at least one of the other classes. I just dont have time to do everything. Right now we are doing a 2-ethyl-1,3-hexanediol conversion to a ketone. A specific reaction. Im trying to figure out why the aldehyde doesnt form. My assumption would be that for the aldehyde to form a primary carbocation would form, which is why that mechanism isnt favored. Any thoughts O Chem comrades? Im looking at a IR spec for the diol, and for my product. they are so awfully similiar that Im forced to admit that I have very little product, and mostly reactant. But my Carbon oxygen double bond is strong[60%transmittance]and no spikes in the 2700 to 2800 range. my first spike is at 2875 which is also in the starting diol.
My next foray starts Monday[which'll be #5] so IM sorry for not letting you in on all the other labs;). Im sure you may have had more important things to do. Tomoorow I start hydrocarbon analysis with Bromine, KMnO4, Ignition, RI, and IR. yippee! Im gonna be a real live Ochemist someday.

posted in Chemistry - 16 replies

GOOD SOURCES FOR CHEMISTRY JOB LISTINGS

2006-07-10T23:26:32Z

Hi,
Anyone got one or two of these?
I have to renew my ACS membership I guess, but does anyone know of any other good sources for job listings?
I'm at Masters level, so bear that in mind.
Thanks e one. ;)

posted in Chemistry - 1 reply

Newbie seeks chemist for answers...

2006-07-10T02:28:35Z

Hi, I'm Denise Denise and I've just joined this tribe.
Why am I here you ask? Well, I'm here to ask a question. The truth is that I'm no chemist and havent ever even taken a college level science class. Do I like Chemistry? I don't really know that much about it to form a preference. What I do like is fire and that's why I'm here.
Boric Acid specifically. I understand that old people soak their feet in this stuff and that it's used as an anti-roach powder.
is it generally toxic?
If I were to mix it in denatured alcohol and light it on fire to create a green flame, would the fumes be toxic? Why and to what degree? Should I be concerned with storing a mix like this?
Can you give me any info that might lead to a greater understanding of safety for this fire spinner? Any info would be much appreciated.

Muchas gracias.
~DD

posted in Chemistry - 7 replies

acid base extraction for kids

2006-07-09T19:44:42Z

I teach a science summer camp and was wondering if anyone had a simple acid/base recipe for extracting caffine from instant coffee that I could do with my class

posted in Chemistry - 1 reply

thesis in one week

2006-06-07T07:29:05Z

SHOOT ME NOW!
;)

posted in Chemistry - 2 replies

UsefulChem project

2006-02-02T14:13:34Z

There appears to be several organic chemistry enthusiasts here who might be interested in new challenges. I run an open science project at http://usefulchem.blogspot.com and would welcome contributions and opinions on the synthetic issues that we face. Most of the posts now focus on the synthesis and testing of new anti-malarial agents based on a diketopiperazine framework. Any help, including identifying commercial sources (or donations) of the starting materials we need (http://usefulchem-molecules.blogspot.com) is welcome.

posted in Chemistry - 0 replies

So whats it like...

2006-01-21T19:59:48Z

To be a chem teacher? My plan is to get my bachleors in chem, then go for a masters in education. Anyone want to put in their 6.02*10^23 cents?

Whats it like to be a chem engineer? Or a environmental chemsit? Or...(Fill in blank here.)

posted in Chemistry - 13 replies

RECRYSTALLIZATION POINTERS PLEASE

2005-12-16T09:12:16Z

Hi all, I'm new but I'm just going to shoot a question:
I am trying to make a POM TMA salt, however, I cannot get the damn thing to recrystallize in CH3CN, and that is my solvent of choice here.
So, let's say after I have made the precipitate and dried it and now I add a minimum of CH3CN, then put it in the freezer, the damn thing won't recrystallize. I 've tried this with the vial cap on and off with parafilm over it. Another student suggested poking holes in the top of the parafilm with a needle, and letting it set for a week. Just to let you know , this hasn't been synthesized before, therefore no seed crystal to work with. I am also trying the glass stirring rod trick and crossing my numbed fingers every day. Anyone else have a suggestion? PLEASE?

posted in Chemistry - 3 replies

Apomorphine synthesis

2005-11-21T06:23:25Z

Has any one found a one pot synthesis or any simple synthesis of apomorphine? just curious, the drug is so expensive, yet looks so easy to sythesize from an organic source? I'm just wondering why such a high price for such a simple molecule?

posted in Chemistry - 3 replies

Clumsy Chemists

2005-11-14T17:29:44Z

I want to buy my own glassware to be able to perform synthesi (if thats how you say it plural!). Any pointers anyone, on price, whereabouts, anything? Any stories of major breakages or funny stuff? I break glassware all the time!

posted in Chemistry - 5 replies

biology chem whatever.

2005-11-09T22:52:55Z

I happened to run across someones notes in my chem class. and at first I thought they were for chem, but then I started reading closer, and found out they were high level bio. So, then whats the difference between chem and bio if they use the same tools, examine the same processes, do the same experiments in a test tube, and speak the same language? I know there is also animal observation in some aspects of biology, but if that only occurs in a few branches of bio, then shouldnt it be separated out from biology?

posted in Chemistry - 2 replies

Labwork

2005-10-29T00:49:28Z

Had a lab today. Was winklers method of finding dissolved O2 in a H2O sample. Was very tedious. I think I did it right. Took bloody long though. Whats the longest lab some of you took? 3 1/2 hours? 4 hours?

posted in Chemistry - 3 replies

SOME POSSIBLY USEFUL POINTERS

2005-10-28T22:42:07Z

Read the problem carefully, moving your lips if necessary.

Find the best way to think of the problem in the most concrete terms.

Draw the problem, if possible.

List the important information items in the problem. (GIVEN AND FIND)

Know the background material for the problems.

Follow the problem-solving method your teacher gives you, if one is given.

Understand and use the units of quantities.

Know your own weakest points so you can be wary of them.

Go back and check your work. Use the units of the measurements to check your work. If the answer does not make sense, something is wrong.

posted in Chemistry - 1 reply

Electron Configurations

2005-10-28T22:35:55Z

Simple question:

Is it possible to understand in depth the mechanisms between electron configurations and atomic orbitals, I mean beyond what they usually teach in chem 101, with only an elementary understanding of calculus? And if so where could I find a more in depth explanation of the mechanisms behing electron configurations?

I'm just not satisfied with the way my chem 101 class is glossing over electron configurations. I want to know *why* atoms tend to be more stable when the orbitals are filled, and *why* sub-orbitals require 2 electrons with opposite spin etc. etc. I know it probably involves some quantum mechanics, but does anyone know of a source that goes more in depth of atomic orbitals than what chem 101 textbooks do?

posted in Chemistry - 3 replies

Ever have fun...

2005-10-28T22:22:31Z

Ever have fun doing chem problems in the back of a book while drinking fine belgian ales and listening to Juno reactor? Fo some reason Im having a ball right now. Doing half cell reactions for school. Finding it really fun. Am I alone in this? Or do other people enjoy practicing various eqns? redox/rate rxn/gibbs. I hope Im not all alone in this, but let me know.

posted in Chemistry - 4 replies

Five-Fold Bond

2005-10-14T20:22:52Z

For the First Time, a Five-Fold Bond

Much of chemistry is about understanding how bonds are made and broken. For most of the history of chemistry, only single, double or triple bonds were known. Multiple bonds are particularly important in carbon chemistry, but only certain metals are theoretically capable of more than triple bonds, said Philip Power, professor of chemistry at UC Davis and senior author on the paper.

The dark red crystals were synthesized by Tailuan (Peter) Nguyen, a graduate student in Power's laboratory. The chromium-based compound is stable at room temperature but decomposes in the presence of water, and spontaneously ignites when exposed to air.

To make the compound, Nguyen and Power attached large carbon-based molecules to chromium atoms, constraining how they could behave. They were then able to coax the chromium atoms to bond with each other. The multiple bonding was confirmed by X-ray crystallography and magnetic measurements.

As far as we know, no comparable compound exists in nature, Power said.

In addition to Nguyen and Power, other authors on the paper were postdoctoral researcher Andrew Sutton, theorist Marcin Brynda and crystallographer James Fettinger at the UC Davis chemistry department; and Gary Long, professor of chemistry at the University of Missouri, Rolla. Peter Klavins and Long Pham at the UC Davis physics department carried out magnetic measurements for the study.

The work is published online in Science Express and will appear in the print version of the journal Science later this year.

Source: UC Davis

http://www.physorg.com/news7244.html

posted in Chemistry - 0 replies

back to school to prove to dad that im no fool

2005-09-17T06:03:45Z

so, after taking a very hectic year off school, im back full force. i decided to take chemistry "just for fun" [i enjoy it, but its hard for me]. ive got a few fairly severe learning disabilities, including but not limited to short term memory loss, and severe dyslexia [verbal and visual]. I did really well in high school chemistry, and all my other classes. graduated with a 3.75gpa, and was in the top 50 out of nearly 400 in my graduating class, but for whatever reason this year, the work just seems insane. Im keeping my head above water, but i really want to do better than just "getting by with a passing grade"... so my question is this.

is anybody who knows basic chemistry an online rat [meaning youre on most all the time] and willing to take chem questions from a silly girl just trying to get an education? i can get a tutor through the school if i need one, but there arent that many and i have a really hectic schedule between work, school and taking care of a 2 year old, so an online tutor would really help.

posted in Chemistry - 0 replies

PROBLEM SOLVING SKILLS IN CHEMISTRY

2005-09-14T18:42:52Z

In general, ACCURACY needs to increase rather than speed. Any technical literature is concentrated, and any form of “speed reading” is a waste of time on informationally dense material. Instead, devices to increase comprehension are necessary, such as mental models, finger counting, lip movement, figure drawing, or reading aloud to another person.

Intelligence may be defined as the ability to do abstract reasoning. Weaker students jumble abstract reasoning from lack of ability to grasp the entire problem at “one shot”. The next step for a weaker student is to give up for lack of a way to even get started. The best students support abstraction with concrete ideas. It is not the ability of the better student to fully grasp the complete abstraction that sets them apart, BUT THE ABILITY TO ORGANIZE A PROBLEM SO THAT NO PART OF IT IS TOO DIFFICULT. The idea behind the abstraction becomes more apparent as the idea is used. Another way to put that is that the better student does not usually have more efficient mental “hardware” but better “software”.

One tool for the development of better methods of problem solving is to take a short standard intelligence test and later analyze the results. The number of correct answers is not the most important data, but the analysis of how to “concrete” each question and how to spot potential errors on a case-by-case basis can help students see some ways to improve their personal analytical reasoning ability.

The use of a standardized test will give an ability to see a broad general group of problems that are each “informationally neutral”, that is, having no need for a body of background information other than the very rudimentary, such as the number system, the alphabet, and the ability to define words. Indeed, on any IQ test some questions require just word definition knowledge. In coursework, though, a body of knowledge is needed to interpret the questions. In chemistry some of this material may have to be known by rote in order to most efficiently perform on tests. Some examples of material that should be know by rote are the symbols of elements, polyatomic ions, some valences, measurements and the conversion factors among them, dimensions and the symbols for them, and some common names for materials. There are several ways to learn rote material, to include flashcards, pair quizzing, mnemonic devices, and reading aloud. Class time is poorly spent on rote material, but it is the teacher's responsibility to point out which material is a candidate for rote learning. There is, unfortunately, no way to “pour” this information into a student. That basic maturity of recognizing something that must be done and DOING it is necessary as a prerequisite.

We say that the math is difficult for the students, but they can do the arithmetic very well on the calculators they have. The real stumbling blocks are difficulties organizing the problem and a lack of background rote information. The problem-solving technique needs to be practiced first with trivial problems and then with increasingly difficult problems. “Practice makes perfect” seems to be true; the best way to learn what can go wrong in a problem is to make the mistake yourself, find the mistake, and learn from your mistake. Again, from the initial observations, any problem that can not be thought out completely in the head needs an overall ‘roadmap’ toward a solution and an orderly implementation of the pathway in which each step is demonstrable. For some good ideas on solving problems that are not the “formal” type of chemistry homework problem, see Polya's book, “How to Solve It.” For chemistry problems involving a formula, one pathway is the W5P method to be introduced later. For most conversion problems (many of the chemistry problems), the Dimensional Analysis system, also to be introduced later, is a splendid framework. The point is that with a good framework in which to think of the problem, a complicated problem is merely a series of simple problems.

posted in Chemistry - 0 replies

SOME POINTERS ON GENERAL STUDYING

2005-09-14T18:42:08Z

Keep up with the course. Catch up as quickly as you can if you fall behind.

Know all rote material perfectly.

Understand all concepts before going on.

Thoroughly memorize all background material you are assigned.You will need it later.

Keep a close watch on the assignments for the course. Call other students if you must.

Find a good place to study. It must be comfortable, quiet, well-lit, and have all the things you need.

Find a good consistent time for studying chemistry.

Review lectures as soon afterward as you can.

Determine which study methods are best for you.

Study with others if it helps you. Choose study partners who are serious about learning.

posted in Chemistry - 0 replies

HOW TO SURVIVE BASIC CHEMISTRY

2005-09-14T18:39:22Z

In many high schools and colleges the basic chemistry course is the one that causes most concern among students. With everything going right, chemistry can be a fun but challenging course. Under poor conditions, your first chemistry course can be a real spittin’, cussin’ nightmare. The study of chemistry may be different from anything else you have ever done. In fact, there are several different topics in chemistry THAT MAY NEED TYPES OF STUDYING TAILORED TO THE TOPIC. Basic chemistry is a survey course in chemistry (That is, it covers a little bit of everything.) with emphasis on common chemicals and study techniques. The aim is to give you some chemical and general scientific literacy rather than train you to be a chemist. This outline is to: (a) tell you what to expect in most courses, (b) show you some methods of study for the course, and (c) show you some directions you can turn to for help, if you should need it.

The most useful advice is to stay up with or ahead of the class. As the Red Queen said to Alice, “Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!” If you fall significantly behind in basic chemistry, it is hard to catch up, but catching up is the only way to continue. The material "snowballs" in this course. By that I mean that the basic facts that need to be learned or memorized at the beginning are going to be used later in the course. Fluency in the basic material is necessary for you to be able to understand and learn the more complex ideas in the course. Chemtutor can help you keep up by showing you study methods, explanations, and other ways to learn the material.

We have found that students do better by having a quiz over a small amount of material. Act as if you will have a quiz every class period. These quizzes would either ask you to memorize some basic material or to use some of the material in a math process or a basic idea about chemistry. Designing and giving yourself quizzes to help you schedule your studying will prepare you for the major tests. Chemtutor usually has a Quickquiz or some math problems available to you to help you. If you are studying with someone, teach it to each other. The teacher always learns more than the student. (If you have it together sufficiently well to present it to someone else, you know it a lot better.)

Many students find studying with others from the same class is a lot of help. If you get together in a group of three or four, you will always have someone to study with. If you study with other students, it is easier to call them for missed assignments if you must be out.

posted in Chemistry - 0 replies

HELP!

2005-08-31T05:32:59Z

SYNTHESIS : A solution of 6.7 g KOH in 100 mL H2O, under an inert atmosphere and magnetically stirred, was brought to 75 °C, and 10 g ergotamine tartrate (ET) added. The reaction mixture turned yellow as the ergotamine went into solution over the course of 1 h. The stirring was continued for an additional 3 h. The reaction mixture was cooled to about 10 °C with an external ice bath, and acidified to a pH of about 3.0 by the dropwise addition of 2.5 N H2SO4. White solids started to appear early in the neutralization; approximately 60 mL of sulfuric acid was required. The reaction mixture was cooled overnight, the solids removed by filtration, and the filter cake washed with 10 mL Et2O. The dry solids were transferred to a beaker, suspended in 50 mL 15 % ammonia in anhydrous ethanol, stirred for 1 h, and separated by decantation. This extraction was repeated, and the original decantation and the second extract combined and filtered to remove a few hundred milligrams of unwanted solids. The clear filtrate was stripped of solvent under vacuum, the residual solids dissolved in 50 mL of 1% aqueous ammonia, and this solution was acidified as before with 2.5 N H2SO4. The precipitated solids were removed by filtration and washed with Et2O until free of color. After drying under vacuum to a constant weight, there was obtained 3.5 g of d-lysergic acid hydrate, which should be stored in a dark, sealed container.
A suspension of 3.15 g d-lysergic acid hydrate and 7.1 g of diethylamine in 150 mL CHCl3 was brought to reflux with stirring. With the external heating removed, there was added 3.4 g POCl3 over the course of 2 min, at a rate sufficient to maintain refluxing conditions. The mixture was held at reflux for an additional 5 min, at which point everything had gone into solution. After returning to room temperature, the solution was added to 200 mL of 1 N NH4OH. The phases were separated, the organic phase dried over anhydrous MgSO4, filtered, and the solvent removed under vacuum. The residue was chromatographed over alumina with elution employing a 3:1 C6H6/CHCl3 mixture, and the collected fraction stripped of solvent under hard vacuum to a constant weight. This free-base solid can be recrystallized from benzene to give white crystals with a melting point of 87-92 °C. IR (in cm-1): 750, 776, 850, 937 and 996, with the carbonyl at 1631. The mass spectrum of the free base has a strong parent peak at mass 323, with sizable fragments at masses of 181, 196, 207 and 221.

This base was dissolved in warm, dry MeOH, using 4 mL per g of product. There was then added dry d-tartaric acid (0.232 g per g of LSD base), and the clear warm solution treated with Et2O dropwise until the cloudiness did not dispel on continued stirring. This opaqueness set to a fine crystalline suspension (this is achieved more quickly with seeding) and the solution allowed to crystallize overnight in the refrigerator. Ambient light should be severely restricted during these procedures. The product was removed by filtration, washed sparingly with cold methanol, with a cold 1:1 MeOH/Et2O mixture, and then dried to constant weight. The white crystalline product was lysergic acid diethylamide tartrate with two molecules of methanol of crystallization, with a mp of about 200 °C with decomposition, and weighed 3.11 g (66%). Repeated recrystallizations from methanol produced a product that became progressively less soluble, and eventually virtually insoluble, as the purity increased. A totally pure salt, when dry and when shaken in the dark, will emit small flashes of white light.

can anyone explain this synthesis is an easy manner? kinda like a synthesis for dummies.... assuming ihave little to no xperience in chemistry could you explain it in lamyans terms? and how likely do you think it would be for an inexperienced chemist to succesfully synthesize this? any help would be greatly appreciated

posted in Chemistry - 3 replies

Computer Aided Chem

2005-08-18T19:21:40Z

Hello, I'm a physics major about to undertake my first college Chem course, and really looking forward to it. I actually had Linus Pauling's textbook General Chemistry lying around my house and have read it off and on for a couple years (I really like the book). I have a student question:

I notice there is a elective class in my college's course catalog for a class on Computer Aided Chemistry. The class was full so I couldn't enroll. But I'm generally an autodidact anyways. I was wondering what is the most proffesional but affordable Computer Aided Chemistry (is it generally abbrieviated to CAC, like CAD?) program out there that I could teach myself? Is there a standard? Is it an affordable standard? And if it's not generally affordable to most students what is a good student alternative? I taught myself how to use Mathematica, so I don't see why I can't teach myself howe to use a CAC program. Any suggestions?

posted in Chemistry - 2 replies

experienced chemist needed

2005-08-12T10:32:30Z

sorry to offer such a vague description but....

an experienced chemist is needed(pay will be provided)... for info on the project PM me or quantaman

posted in Chemistry - 1 reply

Chemistry grad students

2005-07-29T02:42:05Z

Wondering how many chem university students are on here, or if the entire website is bent on street chemistry and drugs, mmmmkaaay?

posted in Chemistry - 5 replies

NMR resources?

2005-05-17T17:38:09Z

So, I am taking second semester oh! chem. I am about to complete the class, but I was wondering if there were any recomended readings, websites, etc. where I can learn more about NMR.
I have developed, well, a sort of fetish for NMR (especially H-NMR) and am now really interested in learning more.

(Or for that matter, if you know of a good book or website that you thought was interesting, lemme know because I really liked the class!)

posted in Chemistry - 4 replies

A good term paper topic?

2005-05-14T01:34:18Z

Hi - I am taking a cell bio course and am writing a paper whose topic has to do with recent (since 1995) medical advances in the treatment of a particular illness from a cell bio perspective.

Can anybody suggest an illness or advance where much progress has been made recently? Perhaps one where the developement created a major paradigm shift in how the disease was viewed. Something where I can show marked a marked evolution in the treatment of the disease overall?

No, I'm not trolling for term paper writers, I can do my own research, just a topic idea. Any suggestions would be great!

Thanks,
Andreas

posted in Chemistry - 2 replies

Chemistry Inspiration?

2005-05-14T01:33:36Z

Hi everybody - I'm currently knee-deep in the study of Organic Chemistry, and I am wondering if anybody here has any suggestions for books or media that might serve to inspire and help me gain a better fundamental understanding of the subject.

I am not talking about specific study guides or anything like that (I have plenty of them). What I'm talking about here is books on subjects where a part of the discussion in order to explain the main topic are subtopics that gives one a better understanding of organic (or any other), chemistry. You know, to start thinking more like a chemist.

If I were studying astronomy or physics for instance, there would be countless NOVA episodes. If I was studying animal behavior, there would be countless of Animal Planet shows or whatnot that would help me understand how astromers, physicists or animal biologists think about their work. In those classes, you can always tell the students that have an edge in understanding a subject because of having spent many hours watching shows like that. They understand somewhat more naturally how experts in those fields view the problems in their fields, and by extention better learn what it is to have those skills.

Can anyone here recommend anything that can help me better acquire the skills of chemistry above and beyond just crankin' out those problems in the books, and can help me start thinking more like a chemist?

Thanks for any info or tips....

- Andreas

posted in Chemistry - 5 replies

Hello

2005-03-27T20:35:58Z

I'm new , I just began a chemistry class(introductory inorganic) that is extremely interesting. I have tons of questions, I'm sure that some of them are pretty ridiculous or are not so simple to answer but I just wanted to see who is on this tribe that I can pick the brains of.

Thanks

posted in Chemistry - 9 replies

we need pictures

2005-01-14T05:13:06Z

does anyone have any cool chem pictures? please post :)

posted in Chemistry - 2 replies

Best viewer?

2004-12-13T16:49:31Z

I'm playing with Chime and Rasmol and wondering if there's a standard or "best" molecule viewer/drawing tool.

posted in Chemistry - 5 replies

ammonia complexing

2004-08-27T20:45:47Z

hey tribesters...
I am searching everywhere to see if someone knows a little something about ammonia. I'm trying to fix ammonia in water (either DI or NaCl water) to test it in a spectrophotometer.

My question is:
does anyone know a cleaner complexing reagent other than citric acid and sodium potassium?

Using this to complex NH3 before adding alkaline KBr before letting it sit for 45 minutes in a warm water bath before adding bleach (CaClO in this case to cut down some of the inorganic junk found in NaClO- no good commercial chemically pure bleach to be found, and solutions by nature are more likely to junk up compared to dry compounds), arsenite, and then my dyes, sulfanilamide and NED solutions.

Anyone know anything about this?
thanks, Cris

posted in Chemistry - 3 replies

Water supplies

2004-08-27T20:42:11Z

(This same contamination effect is being seen in the states from hormones; birth control pills, growth hormones in livestock, etc. -GM)

PROZAC IN UK DRINKING WATER

So many Britons are now taking the antidepressant pharmaceutical drug Prozac that it is showing up in the water supply. With 24 million prescriptions for the "happy pills," the drug is finding its way into the water via treated sewage. Experts are debating the possible impacts to the environment and human health given this new constant exposure to low levels of the antidepressant.

Read more at:
http://www.organicconsumers.org/foodsafety/prozac080904.cfm

posted in Chemistry - 1 reply

Help Please

2004-06-30T01:48:38Z

First off...Hi new to this tribe. Hello to everyone.

It has been yrs. since I had Chemistry and I sucked at it then.

Could someone, please, in idiot terms explain "redox" and "non-redox" to me and how to figure out whether an equation is redox or not. I think I have read my book (which really is hard to understand)x1000. Any help would be great!

Thanks.

posted in Chemistry - 2 replies

Hottest

2004-06-29T01:12:15Z

Does anyone know of a more challenging, profitable, exciting professional aspect of chemistry today than "carbon nanotubes"?

I think that quantum "chemistry" of time-travel and alternate universes might be worth more in payoffs to stockholders (if there were or are any), but I don't think (intuitively) that most people would call that "chemistry" in the classical sense....

Why that is, I am unsure, although I am sure that the quantum mechanical aspects of reality that I am discussing certainly usually are not usually described as being limited within the apellation "chemistry".

What do other chemists/ chem fans think?

posted in Chemistry - 3 replies

Homework Help ~PLEASE

2004-04-11T19:36:50Z

Hi
I need help with balancing a chemical equation...anyone?

Butane Combustion problem:
C(sub4)H(sub10)[butane] + (a)__ (blank quantity)O(sub2)[oxygen] ==> (b)__ (blank quantity)CO(sub 2)[carbondioxide]+ (c)__ (blank quantity) H(sub2)O

easier to look at:
Butane + (a)__Oxygen ==> (b)__ CarbonDioxide + (c)__Water

or:
C4H10 + __O2 ==> __ CO2 + __H2O

The assignment says the problem is "unbalanced" and I need to know the numerical values of (a), (b), and (c) to balance. The second part of the question is "is it permissible for one or more of these numbers to contain a fraction?" These are all gases so I would guess "yes" but am not sure why (pulling on bits a parts from other things I have learned).

Mostly, I am coming up with an odd number of O2 and pretty frustrated with the assignment because this is not for a chem class...it's for Mineral Resources. Help is appreciated. I think if I can understand this I can get the other problems on my own.
Thanks.
-Rhonda

posted in Chemistry - 2 replies

books for sale

2004-04-06T21:13:06Z

I have a number of current intro chem books, any one need some?

I will be selling them on campus (dvc) unless someone wants them here first:

Zumdahl th ed, text and complete solutions guide

Ruso Silver intro chem 2nd ed. and CD
problem guide and work book, study gude and selected solutions.

Timberlake intro to general, organic and biological chem and lab
book --

I also have an answer guide for seager and slahbaugh 3rd ed, intro chem and organic.

Let me know (email me here at tribe) if you are interested and how much you can donate for such lovely books.

cheers

M

posted in Chemistry - 3 replies

Need to know

2003-11-27T18:57:46Z

What oxidation number/s is/are assigned to the oxygen in ozone?

posted in Chemistry - 3 replies

ONLINE HELP

2003-11-14T23:11:37Z

HIGHSCHOOL HELP: (good for any intro chem really)
*******************
http://www.chemistrycoach.com/tutorials-8.htm

http://www.chemistrycoach.com/high.htm

ORGANIC Chem help
*******************
http://www.chemhelper.com/

BASICS:
*******************
http://www.hyper-ad.com/tutoring/chemistry/

posted in Chemistry - 0 replies