Ask MetaFilter questions tagged with chemistry

Where can I learn more about synthetic elements?

mermaidcafe — Mon, 29 Apr 2013 14:15:09 -0800

I'm doing a creative writing project involving the history of synthetic elements. I've exhausted Wikipedia but haven't delved too much into other resources yet. Can someone recommend a website or book or other resource? I don't have a chemistry background, so I prefer information that isn't too technical. Alternately, if anyone here is an expert, feel free to share any info at all--it's all helpful.

Freshly grated parmesan cheese - turns blue in a copper bowl?

mikurski — Wed, 03 Apr 2013 00:28:40 -0800

My SO and I were having some italian-themed chicken wings, and had some fresh-grated parmesan cheese on the side in a copper bowl. After our meal, we were cleaning up and transferring the leftovers to the fridge for storage, and the cheese on the bottom of the bowl had turned a light blue. Does anyone know why this happened? Given that it happened over only a few hours to just the cheese in contact with the bowl, I'm thinking it was some kind of reaction with the copper.

Silent Science Videos To Entertain Teens?

The Whelk — Sun, 24 Mar 2013 12:26:02 -0800

Looking for videos to create a youtube playlist to entertain a group of science-minded teenagers for about 30 min that are largely visual. Sound is fine but the bulk shouldn't be someone talking to the class like an instructor - visualizations are best - ideally they should look really, really cool. Class is engineering focused, but chemistry, robotics, wobbly bridges, comp-sci, biology, are all welcome. Backstory: the kids are going to be holed up in a room for a while without their phones, the projector will be playing a pre-selected set of youtube videos.

What combination of these materials will create a cool reaction?

np312 — Sat, 23 Feb 2013 12:13:43 -0800

Chemistry-buffs, please help! I'm trying to figure out how to create as destructive a chemical reaction as possible (something along the lines of an acid eating through a base) using only limited materials. For story purposes, this reaction has to be created by using some combination of the following materials only: Copper
Bronze
Lead
Iron
Silver or Gold
Sulfur
Salt
Vinegar
Lye
Sodium Carbonate
Potassium Carbonate

PLEASE NOTE: I can't add any other materials, such as hydrogen peroxide or whatnot-- it had to be some combo of the above materials only.

The more violent the reaction the better, with the goal of having the mixture destroy/eat through one of the above materials. For example, merely taking the patina off copper is too weak a reaction to work for my story.

Water and Fire may be employed, but it can't be an experiment requiring any actual laboratory equipment, i.e. it must be simple enough to perform in the wild.

Thanks!

Not-OK Cupid

Anonymous — Mon, 18 Feb 2013 10:11:15 -0800

I've slept with a lot of guys and only enjoyed it with like 10% of them. Are my standards too high, or too low, or what? So I know a lot of people say that chemistry doesn't really matter in the long run in relationships, the spark always fades with time, you shouldn't choose partners just based on whether you feel attracted to them, etc.

Well. I (mid20s lady) very frequently find myself out on dates with guys who are fine! Interesting! Attractive! Funny! But I don't feel a spark. I don't feel attracted, but I don't feel put off or repulsed at all either. The guys are just, like, fine. And I figure- well, I might grow to feel more for them with a little more time and intimacy. (Generally I meet these guys online although not always- sometimes they ask me out IRL.)

And then, often, I hook up with these attractive funny smart guys who I don't feel much of a spark with... and it sucks. The sex just does nothing for me, even if I come. And then my ambivalence turns immediately to a feeling of NOPE NOPE NOPE and I stop seeing them because I realize that, no, I can't fool myself into liking THIS one, either. I can't tell you how many times this has happened. Too many.

I've felt that chemistry I lack with them before, though not very often. I'd say maybe seven or eight guys have made me feel this way- my mood improves when I'm around them, I look forward to the next time I see them, I have engaging conversations with them, and the idea of sex with them turn me on. And every one of them has been a guy I met in real life- NOT a guy from online. Some of those guys have been available, some not for various reasons. I've managed to sleep with two of them, and date one of those two- and I pursued them both initially. And sex with those two was far and away the best sex of my life, no question, not even close. The only times I've felt truly sexy, and the only times I've genuinely enjoyed giving head. The only times I've felt tingly when being touched, instead of feeling... nothing.

But. I don't know. It didn't work out with those two guys... and plenty of the guys I dropped for having no chemistry would probably have been good partners to me... so I'm of two minds. One part wants to stop online dating altogether because 30+ guys and zero chemistry equals bad idea, and get extremely picky about who I choose to sleep with, only doing it with guys who I feel this genuine attraction towards... even if that means going months or years without a date, because it happens so seldom. Another part wants to stop making such immediate assumptions, that just because I feel eh about a guy initially and don't love the sex right away I could never fall in love with him, and try harder and not run away immediately when that happens.

I don't know what to do. I only know that I'm tired of this and one way or another I want to fall in love again.

New job selling laboratory equipment, but have no lab/science experience

AMWKE1984 — Fri, 08 Feb 2013 06:40:32 -0800

I recently accepted a sales position within a company that sells laboratory equipment. (i.e. centrifuges, GC's, HPLC's, Thermal Cyclers, etc) I have no previous lab or science experience, so learning about a myriad of highly technical products/methods is a quite challenging. My main challenge comes from the fact that I need to engage in conversations with scientists, chemists, biologists on a daily basis. With no previous lab experience, I've been having a hard time talking to them on technical level. My biggest fear is asking about their work, and then sounding like an idiot for not knowing what the heck goes into carbon testing or any other lab procedure. (my B.A. is in marketing), so the sales part is not an issue.

Most of the other salespeople here come from lab backgrounds, or have degrees in the sciences. There are a few who are in my age/background who are doing well without the science knowledge.

What I'm looking for is a resource to better understand the flow of a lab. For example, if a lab is doing blood work, how do I know what pieces of lab equipment they are already using, and to maybe help understand the bath that a sample takes. I know I'll never be able to learn what someone has learned in 4-8 years of school/lab work, but I know I have the intangibles and the drive needed to succeed by learning whatever is necessary.

To summarize, what is the best method for me to understand the inner-workings of a lab, in order to at least have an idea of what their equipment needs are. I've found that science types like to talk a lot about the work they do, instead of me just asking if they have any equipment needs.

Thank you so much for the help!

Help me think through Lead in drinking water-- math, chemistry, biology

Anonymous — Tue, 29 Jan 2013 07:37:48 -0800

We're buying a house (still negotiating, hence the anonymity), and we have learned that the level of lead in the water is slightly above the expected range. Not knowing whether this is a big deal, I've tried to do some math to figure out whether being over the threshold is an object of legitimate concern (or whether the range is the fruit of a hyperactive regulatory state) and the process has led me to even more questions. The water test returned a level of 17ppb versus an "action level" of 15ppb. While not an order of magnitude over the limit (the old "action level" was ~3x the current reading, even) or anything, clearly this isn't ideal (and if we didn't have small children, I might even blissfully ignore it as "close enough" and go about my day) so I decided to perform some back-of-the-envelope math and subsequently I've begun to wonder whether this standard is too permissive. Please follow my math below:

A lead concentration of 15 parts per billion (I presume that the standard is set by volume) is roughly equivalent to 171 parts per billion by weight (lead is 11.4x as dense as water.)
A toddler drinks 1.3l of water per day, which weighs 2.86 lb. At 171 parts per billion of lead by weight, 2.86 lb of water contains .000008 ounces of lead. 365 days of this (with full retention) gets us to .0029oz, .08g,or 81,141 micrograms of lead.

Meanwhile, a healthy lead level for a toddler is 2 micrograms/deciliter of blood. Figure a toddler contains 10 deciliters of blood, and conclude that the bloodstream can safely can hold 20 micrograms.

Leading me to conclude that if the blood standards and the water standards are consistent, the permitted annual drinking intake is 4000x the permitted point-in-time blood content. Or I have misplaced a decimal point.

Now, I understand that lead isn't really metabolized and that it settles in the bones. So while I'm clearly over my head here (for starters, I'm comparing a stock and a flow), I'm not satisfied that 15ppb is safe and 17ppb is unsafe and I am rather alarmed. I wonder about the following:

1. I think I got all the conversions right. Did I?
2. Are either the water standard or the blood standard set with rigor? Or have the authorities simply designated some arbitrary percentile cutoffs?
3. Can the blood standard and the water standard be reconciled in a bottom-up fashion using known rates of lead metabolism and absorption? Or is it all top-down slicing?
4. By the time a child reaches 18 years of age, it's conceivable that despite never consuming "unsafe" water, he will have ingested 100,000x the weight of lead that his bloodstream can safely hold. It's quite alarming from a headline perspective (especially given all the "lead is really, really bad for kids" research generated over the past few years). If I knew what I was talking about, would I still be alarmed?

The one I like isn't the one it will probably work out with.

Pericardium — Wed, 23 Jan 2013 16:23:28 -0800

I'm a woman, 20s. I'm talking to two women - A and B. A has everything I want on paper, and there's a spark there... but there's more of a spark with B, who has next to nothing I want on paper. Is it a bad idea to pick B? I'm trying to be vague in case either of them happen to be members here. A has what I know I like in a partner from previous experience - talkative, job, car, outgoing, all around awesome. B has no job, no car and is shy and not very talkative. I also have a difficult time reading her due to aforementioned shyness.

I'm the type of person who likes to talk for hours and hours, likes activity-based things, and likes to be able to read the other person, which matches with A's preferences. B finds activity-things to be awkward due to the talking involved and prefers to do something like watch a movie. I also have a feeling that a lot of social activities I like to do with my partner are going to be out due to B's shyness. I went on two dates with B expecting there to be nothing there, and actually ended up really liking her.

The problem is I feel more sparks/butterflies with B, but I don't know if it could work long-term... A and I have a good long-term outlook and crazy chemistry but now I'm going to know that I could feel more of a spark with someone else. I don't feel anything when I kiss A, but my insides go wild when I kiss B. But I can be weird about kissing and sometimes that has to grow overtime... so I don't know if that should be a factor?

I've been taking things slow and neither person expects exclusivity yet, but with the rate things are going with A and I I'm guessing I'm going to get asked to be exclusive soon. If you were in this situation, who would you pick? Or would you throw them both back into the sea? Or maybe pick A and see if it just takes more time to see if the spark gets to the level it is with B? Is it a horrible, horrible idea to pick B and hope for the best? Am I overthinking all of this?

Smells like SCIENCE

mippy — Wed, 02 Jan 2013 15:34:03 -0800

After dropping chemistry post-GCSEs, I find myself reading a couple of books about perfume construction that have made me realise that molecules are interesting, and that if they're written about for a non-scientific audience, I understand and am engaged by them more. How can I learn more without being scared off by Really Hard Science? And are there other books or articles which deal with the construction of scents and smells? The books I've been reading are two by Chandler Burr - The Perfect Scent, about the development and manufacture of two particular perfumes (one a celebrity perfume, the other by a reknowned 'nose') and The Emperor of Scent, which is about the scientist/writer Luca Turin's theory of how scent is perceived by the nose - but my woeful chemistry/scientific knowledge has led me to put that to one side for the moment until I can understand it better. I also have The Canon, the guide to science for the non-scientific, though I haven't managed to get into it yet.

I've realised I'm fascinated by the descriptions of the chemistry of perfume - the huge companies that develop scents in labs, machines that can break down scents into exact molecular compositions and how some perfumers drop in infinitesmal concentrations of compounds to avoid 'piracy', the ways in which certain synthetics can completely change a smell molecule by molecule, the widely-used molecular compounds that the consumer has come to know as 'citrus' or 'fresh laundry' in household products. I'm interested in the idea that smells or fragrances work because their ingredients are arranged in a particular way on a molecular level, and I'd like to know how and why compounds and elements are used.

If chemistry at school was about this, I would have got an A. But I didn't, and now I'm wondering what else I can read which will hold the same fascination to me without being aimed at people who already have more of a grasp of how molecular structures etc. work, but which won't be difficult for my left brain to parse. Where should I go to learn more?

Other oils to protect steel

gray17 — Fri, 28 Dec 2012 09:37:12 -0800

I play an Array Mbira. The tines are made of spring steel. I have sweaty hands, so the tines tend to rust unless I coat them with oil. The folks who make the instrument recommend 3-In-One Oil, which is what I've been using. Does it contain anything toxic? Are there other oils I could use to protect the tines? The tines have a blue coating but that doesn't stop the rust. The coating has worn off on the tips where I play the instrument.

I occasionally play 12 string guitar as well, but I don't see any rust on the strings.

Polyester-friendly way to remove/dissolve Oasis wet floral foam

Chef Flamboyardee — Sun, 09 Dec 2012 13:49:37 -0800

How to remove/dissolve Oasis wet floral foam? Problem: must be polyester friendly. An art project involved sticking some glass rods into wet floral foam (that green stuff they put flowers in at the florist's), pouring polyester casting resin onto the foam, and then letting it set. The desired end result was this:



\     |     /   <- Glass rods

 \    |    /

==\===|===/==   <- Cast polyester plastic

   \  |  /

There was a release agent on the surface of the foam, but some plastic was able to travel down the glass rods into the holes they made in the foam. As a result, the lower ends of the rods (below the plastic layer) are coated in foam, which has been stuck to the rods via hardened polyester plastic.

The foam needs to go, since the glass and plastic all need to be clear. Is there a way to dissolve the foam without hurting the plastic? (The glass we're not worried about... unless you recommend HF. Which we won't use.) Right now we're planning to try and get the foam off mechanically, but that looks like it's going to be a big job.

(Floral foam is phenol formaldehyde plastic, for what it's worth.)

Bitter aftertaste in apple butter?

caaaaaam — Sat, 10 Nov 2012 18:38:32 -0800

I just made a large batch of apple butter (~8 pecks) in a giant uncoated copper kettle, cooked on top of a wood fire for the better part of the day. The texture is great, but there is a bitter aftertaste (stronger in some parts, like those from the side of the pot, than others) that slightly worries me — what could have caused it, and is it plausibly safe to eat? Sorry in advance for all the details in what boils down (ha) to a "can I eat it?" question, but I'd like to figure out what exactly is going on if possible.

A few possible explanations that I can think of:

1) Leached copper. The bitterness does not taste particularly metallic to me, but I would not be surprised if some amount of copper leached in during cooking.

The kettle is an antique, so had not been used for at least one or two generations. It was originally fairly dirty and tarnished, so I thoroughly scrubbed it with Brasso, then Barkeeper's Friend, and then dish detergent (with plenty of rinsing after each). At the end of cleaning, it was fairly shiny though still had several blackened areas that I could not remove (wood had previously been burnt inside the kettle, probably causing these marks).

Before cooking the apple butter, I also boiled about 2 inches of water in the pot as a final cleaning step and sloshed it around the sides. More of the tarnish disappeared, and the water turned kind of golden. In retrospect, that color change is a little unsettling... but making apple butter is what the kettle is for! So I continued anyways.

One last observation I made, to make things even more unappetizing: after removing the boiled water, and before adding the apples, the hottest part of the empty kettle bottom turned an iridescent blue surrounded by purple and other colors, looking kind of like a gasoline spill sunset. Beautiful— but, food-safe?

2) Peels and/or seeds. Maybe 5% of the total peel, and maybe ten or so seeds probably made it in. We added no extra sugar, so any bitterness from these would probably show through.

3) Smoke, ash. There was plenty of smoke going around as the breeze shifted directions, so some of the acridness could have made its way in.

4) Burning. A small area at the center of the bottom of the pot turned black from where the apple butter burned just a little.

From my framing of the question, perhaps you can tell that my main concern here is trying to convince myself that the apple butter does not contain unsafe levels of copper. I realize that no one can give me a definitive answer, and it is better to err on the side of caution, but if anyone has any experience with something like this, or can think of any tests I can do to narrow things down (other than eating all of it and waiting to see what happens), I'd appreciate your thoughts. Thanks.

Best pipettors for a biology lab

metaBugs — Sat, 03 Nov 2012 04:28:04 -0800

Lab workers: With which brand of pipette driver / pipettor should we stock our lab? My current lab is a mess of pipettors that won't hold a charge, stop mid-use and need shaking to restart, or simply don't work but haven't been discraded because someone might fix them one day. Inevitably, the two reliably working pipettors seem to have powerful migratory and nesting instincts; put one down for ten minutes and it'll find its way into another lab, possibly even into someone's drawer.

We have some money to buy some new pipettors. Huzzah. If you have some rock solid, reliable pipettors that have lasted for a few years (possibly with minor repair or replacing the battery), what brand/model are they?

How do you recognize a gifted chemist?

Egg Shen — Fri, 19 Oct 2012 11:01:39 -0800

How would a graduate chemistry student distinguish themselves as more gifted than their classmates? I am not a chemistry student - graduate or otherwise. I'm just a Breaking Bad fan who assumes that there must be some way that a chemistry professor would consider one student more promising than another - but has no idea how it would happen.

Test scores? Accuracy in handling the flasks and fluids and whatnot? Creative approaches to unsolved questions in the field?

Help me make mag spray and save $20 (SAIT)

jocelmeow — Tue, 09 Oct 2012 11:50:54 -0800

Calling all chemists: I'm trying to recreate a store-bought magnesium gluconate elixir spray and am having some trouble. I use this Vinco brand "ionic" magnesium gluconate spray sublingually to help with sleep. I spray some under my tongue each time I wake during the night. It boosts the amount of mag in my system faster than tablets (which I also take) and helps me get back to sleep.

It works well, but at $20 a bottle, which can get used up in less than a week, it's not a great deal. So I've been trying to achieve a workable homemade version. I'm having two issues:

- The homemade doesn't have the slightly sweet flavor of the store-bought version, and I can't figure out where the sweet flavor in the storebought is coming from. The storebought tastes sort of schnapps-y.

- The homemade also doesn't seem to help get me to sleep anywhere near as well as the store-bought version, and I can't figure out why that might be true. I can't use the homemade alone to get me to sleep; I can either do half a dozen sprays of store-bought or a combo of two sprays of store-bought and a dozen sprays of homemade and get to sleep. No matter how much homemade I use, it alone won't get me down.

- To further complicate matters, the new lot of store-bought I've recently started receiving doesn't work as well as the old (I have tested this blind several times with the same results) so I can't even count on just buying more of the "good stuff." The manufacturer tells me the new lot is "made from the same mother tincture" as the previous one, and they don't know why it's not working.

I have tried to pose innocuous questions to the company in order to find out more about the manufacturing process, but unsurprisingly, they are not forthcoming.

Making the stuff at home:

The store-bought spray is 20% grain alcohol, 80% water, with .89 mg/ml magnesium. The manufacturer told me the alcohol is for suspension and preservative purposes. There are no other ingredients mentioned besides those three.

I bought a bag of magnesium gluconate powder from PureBulk.com and 190 proof grain alcohol from the liquor store.

I figured these amounts out to reach the dosage the store-bought delivers:

5 tsp. magnesium (13000 magnesium gluconate, which is 700 mg elemental magnesium, since it's roughly 5% available)
150 ml 190 proof alcohol
+600 ml water
-------------------------------------
750 ml magnesium spray

Here are the preparation methods we've tried so far:

Method #1: We tried dissolving the magnesium in the water, and despite much warming and stirring, it didn't dissolve before we gave up after a few hours.

Method #2: We tried dissolving it in the grain alcohol, by letting it sit until it dissolved, which worked, then adding the water.

Method #3: We've also tried warming the alcohol slightly and stirring it in, and that caused it to dissolve a bit faster, then adding the water.

The result from both #2 and #3 tastes the same: a little burn-y and slightly bitter, not at all like the sweet schnapps-y, liqueur-like flavor of the storebought.

So my questions for you:

Where the heck is that sweet flavor coming from in the store-bought? Is it possible there's some other ingredient that doesn't need to be listed? Could it be glycerin? What else could it be?

Is there some method of creating this sort of thing that's available to a supplement company that's not possible in my kitchen? Could that mystery method be creating the sweet flavor without any other ingredients?

Is there a place I could send the good stuff to have it tested as to ingredients?

Any ideas on how to replicate the store-bought more successfully?

Thanks, hivemind!

Better living through chemistry?

Lame_username — Wed, 26 Sep 2012 06:57:09 -0800

Are there unpleasant compounds in plastic (specifically Britta filters) that are soluble in pure ethanol that I don't want to drink? I enjoy making home-made liquors (specifically infusions) like limoncello. I use a 190 proof Everclear as my solvent to extract the lemon oils (or fruit or whatever). Based on a tip I read online, my habit is to filter the alcohol in a new Britta filter before I soak the flavoring agent in the alcohol. I know that Everclear is only distilled once and I believe that it contains some impurities that contribute to a very harsh character. I further believe that the charcoal filtration has led to a much smoother taste in my finished product.

However, last night whilst studying to make my latest creation (a raspberry liquor), I came across a claim that highly concentrated alcohol is a very effective solvent for dissolving chemicals out of the plastic. The most knowledgeable sounding folks suggest that it will specifically dissolve the "plasticizer." However, other folks say that the liquor industry uses plastics to ship and store their alcohol and that it must therefore be approved by the FDA.

I'm told that the plastic used by Britta is either NAS (some kind of styrene) or SAN (Styrene Acrylonitrile). I think my pitcher is of the SAN variety, but I'm not entirely certain.

I've tried to find some kind of definitive food safety website, but get myself entangled in lots of unrelated stuff about BPA. My stuff is never heated, but it does make some sense that alcohol is an effective solvent and that Britta probably didn't design for that purpose. For what its worth, the alcohol is in contact with the plastic for perhaps a couple of hours at most. All subsequent steps are in glass. What do you think of the relative risk level?

Is there a brain chemistry boomerang effect?

Anonymous — Thu, 13 Sep 2012 17:48:17 -0800

Can going off and then later back on an antidepressant "do" something to your brain chemistry or is in some other way unsafe or unwise? Ten years ago, I had a number of quite bad things happen and I became clinically depressed. My therapist put me on a low dose of Lexapro, which did wonders. I felt "normal" and discovered that I probably had been low-grade depressed for many, many years prior to the clinical depression episode.

I was on Lexapro with very few side effects for two years, and eventually weaned off of it at the suggestion of a new general practioner (I had moved across country, did not have a therapist, felt fine without one), as life circumstances had changed as I was feeling quite good.

That was five years ago. Though I have bouts of anxiety and can feel myself getting low-grade depressed during times of great stress, I seem to be able to battle it with regular exercise and wholesome outdoor activities. I am glad to have learned what works for me.

Jump forward – several big issues hit at once (grave illness of loved one, financial distress), and I went to see this same doc to ask if he thought my going back on Lexpro would be a good idea. I felt at times as if a crushing depression was just around the corner. My doc was out, and the MD on call that day told me that to go back on an antidepressant was dangerous, as brains often don’t respond the same way to a drug after being off it, and I was, essentially playing with fire as far as my brain chemistry was concerned.

I suspect she had some axe to grind about meds. I had never met her before; when I told her as part of my history discussion that I had depression and PTSD from childhood and had been on meds, including Clonopin and Lexapro, but off of them for several years, she told me people overdiagnosed themselves, overused antidepressants in general, and that she suspected fewer people were clinically depressed than they thought. Which, okay, sometimes, sure, but she implied that I was one of those people and reiterated that going back on anything was really reckless.

I ended up walking out and not getting meds. And while I feel mostly okay, I do wonder if meds would help me get through this extremely lousy time with more resilience. However, I do not want to potentially do something to my brain chemistry that cannot be undone.

I do think she was a jerk, but she planted doubt. Has anyone heard of this? Can going off and then later back on an antidepressant "do" something to your brain chemistry or is in some other way unsafe or unwise?

Chisel me of a chunk of dessert, will ya?

sourwookie — Mon, 20 Aug 2012 11:47:59 -0800

Food chemists! Help me make a sorbet! Challenge level: Spoonable AND sugar free. So the idea is I want to make a sweet creamy fruit sorbet. Traditionally, in addition to fruit purees and juices (ingredients I intend to use) there is a lot of sugar or corn syrup (ingredients I don't intend to use). ARTIFICIAL SWEETENER IS A-OK WITH ME. So if I want to punch up the sweet factor with Splenda, Stevia, etc that's cool.

The problem: I can make a juice/puree/sweetener mix and churn it in my ice cream maker and it's good to go right then. But when I pack it into the freezer for eating later it brickifies due to all the water. The traditional solution (Solution? Ha! Get it?) is to use sugar--lots of it. Or sometimes people will use vodka as an "anti-freeze". The problem with sugar is I don't want to use it and my concern with vodka is that in the absence of sugar I would have to use so much of it I have crossed into something other than dessert territory.

So are there any additives: anti-freezes, emulsifiers, anything to break up those ice crystals and keep it spoonable during storage? I'm not afraid of things not found at the supermarket, so if I have to order something normally used for more commercial use I'm OK with that. Thanks!

Nature's egg timer?

londonmark — Wed, 15 Aug 2012 05:14:57 -0800

What readily available materials change state at a constant, predictable rate in an easily observable manner? As I understand it, carbon dating works because we can calculate the decay of carbon 14 fairly accurately (and apologies to any physisists reading this if that's a sloppy attempt at explaining it). I'm after things that work in a similar fashion, but over much shorter timescales and in an immediately observable way. Like an egg timer, but without the mechanical construction. Are there, for example, any materials that oxidise at a steady state (without the need to control environment)?

Why is baking soda slippery?

Prince_of_Cups — Thu, 05 Jul 2012 11:53:58 -0800

Solutions of baking soda (sodium bicarbonate) and potassium metabisulfite in water are both slippery to the touch. Why is that?

Chemist looking for non-chemistry work

aleatorictelevision — Fri, 11 May 2012 08:09:36 -0800

I'm a current senior graduating with a degree in chemistry from a fairly selective liberal arts problem. The catch is that I really, really do not want a job in a chemistry lab when I graduate. I'm looking for ideas for alternative career options that would be realistic for a chemistry graduate. I've had reserach experience in environmental chemistry(water chemistry), but am not quite sure about grad school and really am not looking forward to a dead-end lab technician job.

I'm utilizing my school's career center and my connections, but I'm mainly just looking for personal stories or ideas.

I would love to have a job in the environmental field, particularly a job that involves being outdoors, but being indoors isn't a dealbreaker.

I have fairly strong quantitative and qualitative reasoning skills and have a fair amount of experience programing. Any ideas?

What ever became of James Burke's little spheres?

This_Will_Be_Good — Wed, 09 May 2012 18:49:36 -0800

In the final episode of James Burke's "Connections", he describes a secret experiment mixing CuSO4 and NaOH, and the potential uses for the result. That was the late 1970s--I am curious what actually happened since then. I was just re-watching James Burke's original "Connections" series. If you haven't watched Connections, I highly recommend it. I think it is one of the most perfectly executed productions I have ever seen, and it bears several re-watchings because you will inevitably fall off track from some rapidly moving historical trajectory and miss something, but also because the more you watch it the more you realize how incredibly thought out every single shot, angle and scene is crafted (the most famous being the rocket launch narration, but I won't spoil that for you with a description).

Anyway, in the last episode of the series, "#10 - Yesterday, Tomorrow and You," Burke is explaining the various levels of understanding technology and science and uses a chemical reaction to demonstrate this. The scene I am talking about is right here in the episode.

He demonstrates the mixture of two liquids, which has the unusual result of producing little spheres. I am fairly certain that he states that the two liquids in the mixture are CuSO4 and NaOH.

The experiment to produce "those little spheres" was being conducted at "Harwell" by the Atomic Energy Authority. Burke seemed to imply that the work was secret and that he is only allowed to tell you a few things. A few of the potential uses he says are to:

1) produce more efficient nuclear fuel
2) to help find oil
3) to put a drug in your body to allow it to act at a certain time
4) determine if your blood vessels are working properly or not

The series aired in the late 1970s, so there has been a lot of time since they started producing those little spheres. Since I know so little about chemistry, I am curious about what this "secret" reaction was, and what exactly--if anything--came about from that research.

I am guessing for (3) that maybe the little spheres were like those seen in time-release medicine capsules, and for (4) it is like some of those tests where they inject these nano-balls into blood to see if there are internal bleeds, or holes, or perforations. I guess the same thing could be how (2) is used? I have no guess for (1).

My limited blind googling around led me to believe that the reaction was Copper Sulfate and Sodium Hydroxide, and perhaps the result was Copper Hydroxide--which led me to Dupont Kocide, which is some sort of copper fungicide/bactericide. Although, if 1-4 turned out to be false, and the final result was a plant fungicide, than that would fit in just perfectly with all the random mistakes with fortunate results that the entire series features.

As a bonus question from the same episode: at this point right before showing the little spheres, Burke is standing on a catwalk above spent fuel rods at a nuclear power plant. Is that safe or is that insane (though I can see him taking that risk for the perfect shot)?

Getting into chemistry grad school with no chemistry background?

nhamann — Sun, 29 Apr 2012 13:00:36 -0800

I would like to pursue research in supramolecular chemistry, but I am a couple years out of school and do not have a chemistry background. Also, I lack letters of recommendation. I am certain I cannot get into a decent Ph.D. program, but do I have a shot at getting in a Master's program? Or must I resort to taking classes at a university somewhere? Some background: I graduated in May 2009 with a B.S. in electrical engineering. I graduated summa cum laude (3.95 GPA) and attended on a full-tuition academic scholarship.

I took a semester off and went back to school for two semesters starting in January 2010. I took classes in Math and CS and was in the process of applying for the Master's program in Math, but halfway through the second semester I realized that my interests were not in math. Demoralized, I stopped attending classes. So I got a 4.0 my first semester, and something bad my second semester (two C's, an F and an incomplete, last I checked). My cumulative GPA is at 3.8.

Since then I've been working in IT and studying in my free time.

Given my lack of background in chemistry (the last chemistry class I took was in sophomore year of high school), I'm assuming I can't get into any Ph.D. program. Getting into a terminal Master's program seems potentially doable, but I did not cultivate a network while in school, so my letters of recommendation will be either crappy or non-existant. How competitive are terminal master's programs in chemistry? Will I be fine with bad letters of recommendation if I kill the GRE subject test?

A last resort I have thought of would be either sitting in on or taking chemistry classes at a university somewhere in order to get letters of recommendation, but I enjoy self-study and would like to avoid having to pay for expensive chemistry courses if at all possible. Are there other options here that I have not considered?

Hemp me dehumidify

Long Way To Go — Wed, 25 Apr 2012 11:34:00 -0800

How can I quickly reduce relative humidity in a small enclosed environment within a fume hood without raising air temperature? We have a small chamber (30x30x30cm) inside a fume hood. The chamber is not gas tight, it just serves to protect the apparatus inside from the fast moving air outside (i.e. the fume hood environment). We do this because we're drying a film on glass inside the chamber and we want it to dry in still air so that it drys as evenly as possible.

Our problem is relative humidity, which we need to keep at about 25% to make good film. For safety reasons the lab has to be a single pass air system, that means that the air conditioner takes whatever air mother nature gives us does its best to heat or cool it and pumps that into the lab, then the fume hoods suck that out and dump it. It doesn't get recirculated because it contains the bad stuff from the fume hood. Thus the air handler only gets one pass at conditioning and so we have poor control of humidity within the lab. What we want is a way to aggressively remove moisture from the air within that small chamber.

Here's what we're already doing or thinking about:

Today we heat the air inside the chamber which reduces the RH, but the increased temperature also interferes with the film formation.

Typical desiccants like silica gel just don't work fast enough.

We are looking at pumping dry compressed air or dry nitrogen into the chamber.

What I would really like is a vigorous chemical reaction that strips water out of the air. We're a chemistry R&D company so we should have no problem acquiring the materials.

Organic chemistry reaction/reagent database for a student?

sunnichka — Sat, 21 Apr 2012 19:58:01 -0800

I'm studying for my organic chemistry I final exam and I'm looking for some sort of searchable database of reactions and reagents to help me solve problems. For example, right now I am stuck because I can't figure out how a 6 carbon molecule with an epoxide ring on one end and a double bond on the other end will react when treated with NaOEt and EtOH at 60 degrees Celsius. (Next it's treated with TsCl/pyradine and then NaCN/DMF and I have a faint idea that I'm going to be able to deal with that.) I've been searching through my textbook and tried googling it but the google results were too chemically complicated for me to extract any useful info.

Does anybody know of a resource to help me find this kind of info?

Bonus points if you can expand on what my professor said on the last day of class: that to figure out most syntheses, you should look at the target molecule, decide what's been added, and then decide if these functional groups have been added as an electrophile or a nucleophile.

This seems very sensible to me, but my first problem is that I'm getting confused about identifying nucleophiles from electrophiles. And my second problem is well, how on earth do I condense all these different reactions I've learned into just "adding as an electrophile or a nucleophile"??