Ask MetaFilter questions tagged with chemistry

Most effective means of moving hot air?

ascetic — Wed, 16 Dec 2009 13:24:48 -0800

What is the best way to move hot air? Would it be blowing air across the heat source (ex: wood stove) or suck the air away from the heat source? I use a wood stove to heat my home which works perfectly, but it occasionally gets too hot in the living room (where the wood stove is). I want to disperse some of this excess heat into the other rooms.

Clean up copper sulfate spill?

miyabo — Fri, 11 Dec 2009 14:14:27 -0800

ToxicWasteFilter: How do I clean up a copper sulfate spill? I tried to clean out my backed-up sewer with copper sulfate. I poured it down the toilet, flushed...and it came right up the basement drain. The basement drain water/copper sulfate solution has now dried, leaving a whitish-blue layer on a few square feet of the basement floor. I'd like to let pets and people into the basement again, so I really want to clean the stuff up.

Is this something I can clean up with an industrial mop? Do I need to mix the solution with quicklime or soda ash to neutralize it, as is suggested in this MSDS? Is there someone I can hire to do this for me?

Please don't criticize me for using a bad-for-the-environment cleaning chemical. I went to every hardware store I can find looking for the nontoxic stuff (RootX), but no one had it in stock.

Not that I don't like it when non-violent protesters get permanant lung damage, but...

Truthiness — Thu, 10 Dec 2009 01:36:20 -0800

NoveltyUseOnlyFilter: Chemists- do you think it would be possible to develop a chemical compound (aerosol? liquid?) which could counter tear gas by causing it to break down/change phase? Like I said, this is a PURELY theoretical question. I would never actually want to subvert any kind of authority. That said, I am rather curious. Compounds commonly used as tear gas:

CS Gas

CN Gas

CR Gas

Do you think the development of a counter-agent could be possible?

Chocolate Chip Cookie Chemistry

ACF — Wed, 09 Dec 2009 00:02:03 -0800

I'm baking chocolate chip cookies and after looking at some recipes, I realized that they all use baking soda (not baking powder) as the leavening agent. The explanation is that baking soda interacts with the acids in the chocolate to produce the leavening CO2. My question is this: Can I freeze my baking soda leavened dough? Can I leave it in the fridge until I'm ready to bake? The chemistry suggests the answer is no, because the reaction between the baking soda and the chocolate starts immediately, and so the dough needs to baked right away. But there are plenty of people who freeze chocolate chip cookie dough for later use. Is there something I don't understand about the baking chemistry? Or are people who are taking the dough out of their freezer just eating unleavened cookie-pucks?

How do you get from here to there....?

bolognius maximus — Sun, 06 Dec 2009 14:33:48 -0800

Organic Chemistry filter: I just want to make sure I'm doing this right... Yes, this is a homework problem. I admit it freely. But I put the time into it, and just want to make sure that I'm on the right track. I think I have it right. It seems pretty straightforward. If anyone can tell me if I am not thinking about it right or if I am on the right track, I would really appreciate it.

The problem: provide syntheses (should take 3 steps) to get from 1-butanol to hexene, from only the starting material and reagents or compounds with 2 carbons or less.

My answer:
Step 1: I used PBr3 to turn 1-butanol into 1-bromo butane + HoPBr2.
Step 2: I used an ethyne anion (via E2) to turn the 1-bromo butane
into 1-hexyne.
Step 3: I used 2 mol of H2 and a Pd catalyst to convert the
1-hexyne to hexene.

I hope I did this right! Can someone please let me know, and if not, tell me what direction to look in? Thank you!

what's the science? and should i drink it?

msconduct — Mon, 30 Nov 2009 17:43:57 -0800

my mother used to put a few drops of hydrogen peroxide in milk to keep it fresh past the 'use by' date. it appears to work. very well. what's the chemistry behind this? and should i drink it?

Help me determine the chemical makeup of...well...everything!

Anonymous — Mon, 16 Nov 2009 19:12:56 -0800

What type of equipment is necessary to determine the chemical makeup of a given substance, is such equipment available to the general public, and if so at what cost? I have always been fascinated by shows such as CSI where someone is given sample evidence, a scraping is taken of this evidence, put into a solution, and then a device is used to determine what was actually in the sample.

Is this pure fiction, or do such things exist? What equipment would be necessary to, for instance, tell you what that smear on your shoe is, how much caffeine is in that cup of unknown liquid, or what makes up that pressed pill you bought from the dude on your street corner? Is this the sort of thing that only exists in a television writer's dream, or can someone purchase a device or devices that will replicate this process?

Thick + Thick = Thin?

Rafaelloello — Fri, 23 Oct 2009 18:30:30 -0800

What happened to my Shampoo? I mixed two different Shampoo brands about 70/30 and liked the resultant mixture. The next time I mixed them 50/50 and overnight the mixture lost all it's "thickness" (viscosity, I guess) and still works fine, but is as thin as milk if not thinner. The two brands are Pert Plus and Avalon Organic Botanicals "Nourishing Shampoo" (bought at Trader Joe's). I *believe*, but am not totally sure, that the Pert Plus was the 70 per cent one when it worked fine the first time.

Uh...hang on, just give me a minute.

Demogorgon — Mon, 12 Oct 2009 10:34:31 -0800

What is the most important scientific question of our time? I volunteer at an observatory for a local amateur astronomers' society and one of the guests at a recent star party came up and asked, "What do you think is the most important question science has to answer right now?" Obviously, there is no right or wrong answer, but after the party was over a lot of us were still talking about this question and I ended up learning a great deal from my fellow club members that I might otherwise not have.
The next time this question gets asked I want to be prepared to offer a variety of answers from differing fields and opinions. I don't expect to represent every answer as an expert, but I'd like to be able to give a few more examples than I was able to, and then correlate them to some book recommendations from the answers in this thread about introductions to your field.
I also think it is important to frame the question in a way that can be meaningfully answered, i.e. "What is the most important scientific discovery about to be made?" or something like that.
Of course, I had my own answer in mind, but as a relative layperson to that branch of study I had a really hard time articulating why it was so important to "science." Therefore, if you are uniquely affiliated with a specific field that you think will produce a game-changer, feel free to get as technical as you're comfortable doing.

Thanks!

Hydrogen and Oxygen bond to make water... but why?

Vorteks — Thu, 24 Sep 2009 09:39:54 -0800

Please help me really grok chemistry. TMBG's recent song "meet the elements" has got me thinking more about chemistry recently. I never really studied it when I was younger, but I've developed more of an interest now.

I understand certain basic concepts - atoms are made of protons, neutrons, and electrons, atoms combine to make molecules, etc, but I don't really "get" it. When you combine, say, vinegar and baking soda, what's really happening at the atomic level? Why do different combination of 3 basic particles behave so differently? Why do some molecules have more potential energy than others? These things escape me.

If there's anything that's helped you really understand this topic, please recommend it! Books, games, documentaries, websites, youtube movies, anything is fair game. I'm not afraid of college-level math, but I find the "dry" writing style often found in textbooks, scientific papers, and encyclopedias very hard to pay attention to. Something with an amusing writing style, or with a large visual component (videos, diagrams, charts, whatever), or with very down-to-earth language would be most effective, I feel.

Thanks in advance Mefites!

I don't understand physics. How do atomic orbitals work?

jeb — Mon, 21 Sep 2009 19:39:32 -0800

I don't understand physics. How do atomic orbitals work? I don't know anything about modern physics beyond the "I watched a trippy special on the Discovery Channel" level Consider this situation: I have one atom of hydrogen. Bound to it is a single electron in the 1s orbital. This electron has a negative charge. As I understand it, the orbital describes a probability density function: if I sample a point in the physical space described by the orbital, the value of that point in associated probability density function is the probability that I will encounter the electron there when I look for it (bonus side question: so if I integrate across the three dimensions of the orbital do I end up with 1?).

Let's assume I set up the following apparatus: I have my atom. At a fixed point from my atom, I have a very tiny electric field meter. This meter will record the strength of electric fields you put it in. I start recording the field strength. What do I see?

a) an oscillating value: the electron being a charged particle creates an electric field that falls off with distance to the meter. When the electron is closest to the meter, it registers the strongest field, and when it is further, it registers the weakest. The rest of the time it careens through points in between (bonus side question if this is the answer: is the output of the meter smooth, continuous, differentiable, etc., because the electron is careening through the physical space the orbital is defined over, or is it just bliz-blaz-bloz because the electron is teleporting to wherever it feels like?)

b) a fixed value: the field the meter would pick up if a point charge equal to the electron was fixed at some point (i don't know, maybe the closest point?) to the meter.

c) a different fixed value: something like the average charge. because quantum mechanics is mad trippy, the charge meter picks up, at all times, the sum of the charge it would detect from a point charge at each point in the orbital over the volume of the orbital.

d) something completely different.

e) Moo. The poster's understanding of the atom is so far wrong that this question cannot be answered.

(Super-bonus question: I'm not in school or anything, but I still want to learn some basics about how these things work. Is this physics or chemistry? Personally, I'm more interested in going up from here into how these work in groups than down into what makes up the various components at this point. Can you recommend any resources whereby I can teach myself? On Amazon, its easy to identify the "Grand Textbook for People Taking Multiple Years of This With Professors, TAs, and Problem Sets" and the "Kind of Trippy Pop Science Book That A Professor Wrote So He Could Get On The Daily Show", but what is in between? I took a lot of math, hard science, and engineering in undergrad, but no physics beyond classical mechanics and no chem so I don't know any of this stuff. I don't want to read a book thats like "Did you know that Quantum Mechanics begins with a 'Q'? That is a very unusual letter, my friends!" but I also don't want to read a book thats like "Page 1: As you can clearly see from the following Lagrangian Chapters 1-10 as listed in the table of contents can be left as an exercise to the reader so your authors have decided to proceed from the beginning of Chapter 11. More specifically, its the eighth page of Chapter 11 so it begins mid-sentence."

What's the best way to study for organic chemistry and/or anatomy?

melodykramer — Tue, 15 Sep 2009 18:09:59 -0800

What are your best study strategies for learning organic chemistry and/or anatomy? I'm doing a post-bac premed year, and I'm taking anatomy, organic chemistry and physics (plus labs) all at once so that I can enter medical school next fall. (I was conditionally accepted pending the necessary GPA/MCAT scores this year.)

I'm finding myself become overwhelmed by the shear breadth of material to learn. I'm trying to break it up but it's still rather difficult to learn these subjects at once -- because for two of them, at least, I'm basically memorizing everything (orgo and anatomy) and am finding myself not able to retain everything.

I'm sure a lot of people here have taken these subjects. So...if you have...what should I do (considering it's early September) to make sure the year is successful? Any helpful little tips? Anything to do in particular?

Thank you in advance.

BeautyNerdFilter: Luck with homemade Vitamin C serums?

airguitar2 — Wed, 12 Aug 2009 11:40:17 -0800

BeautyNerdFilter: Luck with homemade Vitamin C facial serums? (Chemists welcome!) I've recently found some recipes online and have been experimenting with making my own vitamin C facial serum, using l-ascorbic acid crystals dissolved in vegetable glycerin and distilled water. (A number of studies that show the topical use of Vitamin C improves the skin through boosting collagen synthesis.)

Questions

1. Could I be doing any damage by applying vitamin C directly to the skin? This morning my cheeks felt a little rough, and I started to worry that I might have done some harm!

2. Do I need to worry about the ph level?

I'd love to hear from folks who have used a similar concoction, or any chemists/cosmetic scientists who might know about possible consequences... I realize this is a fairly specialized questions-- any specialists out there with some ideas? Thanks!

Know any colors that changed the world?

Ziggurat — Mon, 10 Aug 2009 17:48:38 -0800

Can you think of an example of when a color could be said to have "changed the world"? I'm writing an article/blog post (for $$$, albeit a modest amount, so if that makes you less inclined to help, I'd certainly understand) and I'm looking for just one or two more good examples of instances where a color somehow changed the world. The examples I have so far are pretty historical, but I'm not necessarily limiting myself to that. To give you an idea of what I'm looking for, here's a couple of the ones I have already: Carmine (red dye) the trade in which was an important impetus to European expansion into the Americas; Mauve, the "invention" of which paved the way for chemistry to take its place as an important science for industry; Red (ochre), the first color used in human art; Indigo, like carmine, was a desired pigment and was instrumental in expanding world trade.

A couple other things I researched, so far fruitlessly, were things like:
The lead in white face paint favored by English royalty at one time, caused health issues. I was looking for a case where that could be linked to the premature death of someone historically important, but I couldn't find anything.
In science, is there any case where a particular breakthrough happened in a way that was somehow related to color. Or is there some important invention that could only exist because of a particular color (as in the mauve example above)

Beyond that, I'm open to other ideas, as long as they're very related to a particular color, and were "world changing".

What I'm not really looking for are cases where a color may be a symbol of something...i.e. Red as a symbol of the Soviet revolution, and, later, communism as a whole. I know that distinction may be a bit arbitrary, but hopefully it makes sense!

Thanks a lot!

Is there such as things as too much dating?

Anonymous — Mon, 10 Aug 2009 07:21:26 -0800

I feel like I am exerting a lot of energy towards dating without much return. I have fun while doing it, but since I rarely meet someone who lasts more than a date or two, it’s starting to feel like an exercise in futility. I have dating quantity, but how do I get quality? Obligatory History [aka too much information and self-justification, but of course, open to criticism]:

I’m female, mid-twenties, and sexually attracted to men. I really like meeting new people and going on dates. I’m good at first date small talk. I have eclectic taste, and enjoy hearing about people’s lives. I like men, I like feeling feminine and I like flirting. I am somewhat picky about whom I go out with, since I’m really happy with where I’m at in my life, but that just means that as long as I don't get "creep" vibe, I generally say “yes” whenever I get asked out. I don’t play games (the Rules, etc.,), but I don’t feel desperate. I’m cautious and traditional, so first and second dates are casual and non-physical, for the most part.

Over the last year, I’ve really made an effort to be open to meeting men, even though it’s harder now that I am out of college.
I’ve:
Gone out with men who are not necessarily my type, physically or personality-wise.
Given men my phone number.
Gone out with men that I’ve met online.
Spent time doing what I enjoy doing (classes, gym, volunteering) and have thus met men with similar interests.

The problem is that despite meeting lots of great men, I have yet to "click" with a guy...who is actually single, straight, and available -- the sad truth, as much as I loathe sounding like a rerun of "Sex and the City."

I don’t want anything serious right away; I don’t want to be married right now nor do I believe in the notion of soulmates. However, to be mutually attracted to someone physically and intellectually, long enough to date for even a month or two sounds like heaven at this point.
"Chemistry “ is starting to feel like a romantic fantasy, something akin to waiting for Prince Charming.

Sometimes the men are unavailable or just not interested in going out again, but for the most part, I end things after a date or two or three.
I’ve been told by friends that I’m too picky, or that I am too much of a minority (religious and liberal), but isn’t the idea of a connection that you just feel it? I agree that it is picky to judge guys on looks, income level or education, but if you don't feel an attraction, or if you don't share a sense of humor, or if they are so dull you'd rather go home and do laundry, then I think it is nicer to just break it off, so I do.

I feel too young to be burnt out, so I need some new ideas about where to go from here, some encouraging stories or a (not too harsh!) reality check.

email: datinganddisappointed@gmail.com

hotdogfilter - Why do BallPark Franks plump when you cook them?

Paleoindian — Thu, 06 Aug 2009 22:12:21 -0800

hotdogfilter - Why do BallPark Franks plump when you cook them? remember the commercials that claim "ballpark franks plump when you cook them" and showed the hotdogs swelling on a grill?

Why? Is it all dogs or just Ballpark? ...Why do they "plump"?

What is that strange acrid smell whle showering

srboisvert — Fri, 24 Jul 2009 07:58:18 -0800

My shower (an in-stall water heater) sometimes smells like something rubber is burning. It's a strong acrid smell that I only notice while in the shower and usually only after a sweaty workout. There is no sign of smoke like you would expect with burning rubber. Is this just some sort of weird sweat and treated water chemical reaction? Anybody heard of something like this?

How does silica lower a tire's rolling resistance?

tronec — Wed, 22 Jul 2009 18:04:40 -0800

Physics/chemistry/tire tread composition filter. Why does adding silica to the rubber compound in a tire tread reduce rolling resistance? In quest for better fuel economy, I understand that tire manufacturers continue to experiment with the tread compound to make them roll with less resistance while still retaining adequate friction with the road for starting and stopping. I believe recent tires use more silica and less carbon black to reduce rolling resistance.

I'm not a scientist, and I'm having a hard time wrapping my mind around how adding silica to rubber would cause it to roll with less resistance. Any thoughts would be appreciated.

Peeing for science!

elizardbits — Sun, 05 Jul 2009 09:28:46 -0800

PeeChemistryFilter: what the hell is going on here? When I had my first wee of the day this morning, I noticed something rather bizarre. Some of my pee seems to have formed a grayish-yellow precipitate upon hitting the water in the bowl. I say precipitate rather than sediment, because further experimentation (ok, I peed in a nonsterile plastic cup and stirred it with a nonsterile chopstick) showed neither sediment nor precipitate. This leads me to believe that some combination of substances in my wee and substances with which I clean my toilet have formed a chemical reaction. (I realize this is a pretty lame hypothesis, scientifically speaking, but it's all I've got. CURSES.)

My question is thus twofold:
01. ~~OH GOD AM I DYING?~~ Does this seem like an urgent medical situation in any way? There's no pain or burning sensation before, during, or after urination, I have no fever, there is no blood or pus present in my wee, and I have no tenderness in the kidney, bladder, or urethra areas.

02. What the hell could be causing this? For reference purposes, the medications I'm currently taking are:
-20mg adderall/daily, for the past 2 years
-triam/HCTZ 37.5/25 (1 cap yesterday morning)
-ProAir HFA (1 puff shortly before bedtime last night)

I also drank rather a lot on Friday night - mostly beers, but I think I recall some mysterious fruity pink shots. To my knowledge, I haven't had any kind of recreational drugs, and I have no reason to suspect that any of my friends might have sneakily given me something Friday night.

Lastly, I clean my toilet with Scrubbing Bubbles FreshBrush Flushables, most recently on Wednesday of last week. Also, the water in my building has a slightly elevated lead content, but is within the legal limits for NYC.

In conclusion, WTF?

What combinations of clear, non-toxic chemicals create a colourful result?

greatgefilte — Fri, 03 Jul 2009 16:17:56 -0800

What combinations of colourless non-toxic substances result in something that's coloured, or at least opaque? Aside from enzymes and substrates, are there any safe organic and/or inorganic clear substances that are known to change colour in the right combination? I vaguely remember doing things like this with a childhood chemistry set, but can't remember the specifics.

Propane grills with less-than-high-grade propane?

phantroll — Thu, 11 Jun 2009 10:41:16 -0800

Is my propane grill going to work if the gas supply isn't up to U.S. standard? I bought a propane grill in Mexico City, and the fine folks at Home Depot also sold us a 10-liter propane tank (which, incidentally, doesn't fit on the little shelf parts on the grill and has to rest on the ground).

The only way we've figured out to fill the propane tank is through the guys who drive trucks around the neighborhoods here selling refills of the tanks some people use for cooking and water heating here. (We have natural gas lines in our apartment so haven't used the gas truck before.) We gave our propane tank to the gas guys and they returned it, filled, two days later.

The Wikipedia entry on propane notes that in other countries, particularly in Mexico, the "propane" typically has a higher butane content than the standard requires in the U.S. I have no idea what exactly these gas dudes in Mexico put in my tank, and I would really like to avoid setting myself on fire. Think it's OK to use what they gave me?

The grill is made by Brinkmann, a U.S. manufacturer, and the same model is sold in the U.S.

(Side note: I did connect the tank to my grill already, did a leak test as the owner's manual instructs, and found a leak in the regulator. I'm hoping that this doesn't have something to do with the gas mix and is an honest-to-goodness manufacturer's defect. I'm ordering a replacement part.)

The answers always fade too soon.

dmd — Tue, 09 Jun 2009 10:18:10 -0800

Why does UV make things fade? I've read this and this and lots of other things, but their explanations always end at "UV causes chemical bonds to break".

Why does this bond-breaking tend to cause the surface to reflect more light? I.e., why do smaller molecules tend to reflect more light than larger ones?

Is espresso hot chocolate impossible?

goo — Sat, 06 Jun 2009 19:26:44 -0800

Chocolate espresso - impossible? I want to make espresso hot chocolate, but after reading up it seems as though it's not doable. At all. Am I right? I want to make hot chocolate using my espresso machine. Initially I searched for insoluble chocolate thinking I could just run it through the machine as I would coffee, but such a thing doesn't seem to exist, and after doing some reading it looks like cacao beans need to be heavily processed before resembling chocolate.

I've read up on home-roasting cacao beans, but apparently that still wouldn't get me what I want as cacao beans are extremely bitter before processing, and need milk proteins and sugar to taste anything like chocolate (which doesn't actually make sense to me, as good dark chocolate doesn't contain any milk proteins, but that's what I read). Could I add milk and sugar after making the espresso to get the same effect?

I'm going to buy some cacao beans and experiment, but thought the hive mind could help as my chemistry and chocolate understandings are pretty basic overall! To summarise;
- will I totally be wasting money and time buying and roasting cacao beans in order to try to make espresso chocolate?
- if I make espresso chocolate, using an espresso machine and some ground, roasted cacao beans, will it be totally disgusting?
- will it be disgusting even if I add milk and sugar afterward? Or should I think about how to add milk and sugar to the ground beans before running it through the espresso machine?

I have an electric bench-top machine and a stovetop mokka pot I can use, if that makes a difference.

Thanks for your help!

Pardon me, but do you speak chemistry?

neurodoc — Tue, 02 Jun 2009 13:03:46 -0800

Looking for a chemistry wizard to help me translate this ad. In cleaning out some old files, I came across this ad (and several others) from my grad school days. While I remembered most of the chemistry on the other ones, this one has me stumped. All I can read is the "007" part.

Thanks, and as a reward I'd be glad to scan the other three that I have and put them up for folks to see. Surprisingly, I couldn't find them on the web anywhere.

Molecular cartography - how's it done?

shivohum — Sun, 31 May 2009 07:11:29 -0800

What techniques do chemists use to map the molecular structure of a substance?