General Questions

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Anyone has an idea of how much blank DVD-R/DVD-RW (the small DVD CDs) cost? Just got my hands on a Vario Tessar.
 
What does it mean if one of my fingers has little or no cuticle?
 
It means you must've lost it somewhere.

Now focus, where were you when you've last seen it?
 
Loon
I noticed it when I was cutting my fingernails, all but one have a big cuticle.
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Maybe that's the normal cuticle and it's the other nine you should be worrying about.
 
I have a chemistry test tomorrow (sounds familiar) and I just have two simple questions.

C3H4(g) + O2(g) --> 2H2O(l) + C3(s)

First of all, in that synthesis reaction would the product be correct?

Second of all, if it is correct, would Carbon turn back into a solid?

EDIT: I'm also having a hard time finding the name for H2O(g). Any help would be greatly appreciated.
 
It's balanced, not sure if its necessarily correct. And I believe the gaseous state of H2O would be steam.
 
Diablo'
I have a chemistry test tomorrow (sounds familiar) and I just have two simple questions.

C3H4(g) + O2(g) --> 2H2O(l) + C3(s)

First of all, in that synthesis reaction would the product be correct?

Second of all, if it is correct, would Carbon turn back into a solid?

EDIT: I'm also having a hard time finding the name for H2O(g). Any help would be greatly appreciated.
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Is C3H4 a valid hydrocarbon? It's a long time since I studied Chemistry, but wouldn't the minimum number of hydrogen atoms be 7? As in CH3CH2CH3? As far as I can remember, you need Oxygen or Chlorine (or some other highly negative-valent atom) to be present to cause Carbon to double-bond with itself.

Carbon can turn back into a solid when there is insufficient oxygen: this is what causes soot from candles. I'm not convinced by the lack of CO2 in your equation though. As Loon says, I don't think your equation is right.
 
GilesGuthrie
Is C3H4 a valid hydrocarbon?
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No. If it was a monomer it would have to have 3 Carbons and 8 Hydrogens. But if it was a polymer it would have to have 3 Carbons and 6 Hydrogens.
 
You can have C3H4, i.e. H2C=C=CH2 or a cyclic C3 with a single double bond between two Carbons... hydrocarbons can have C=C's without anything other than C and H in them, e.g alkenes. Without knowing the full question, I would have also thought that a hydrocarbon plus oxygen (i.e. combustion) would result in H2O and CO2... did it ask you just what the products would be, or what the products would be and then to balance the equation? Since you could have written C3H4 + 402 => 3CO2 + 2H2O...
 
Metar
...and that's why I chose Physics.
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I actually switched out of physics to take this *facepalm*


C3H4(g) + O2(g) -->

The original question shows that (plus a few others) and says:

"Predict whether each of the following chemical reactions will occur. For each reaction that will occur, identify the reaction type and complete the chemical equation"
 
Well, as the Wiki article points out, it’s an essential amino acid – usually that’s a pretty good indicator of something being okay for you. ;) (Plus it’s in a Listerine pak – how dangerous are those?) Of course, if you have phenylketonuria, then it’s not something you should be taking in, but if you don’t already know what phenylketonuria is, then you don’t have it.
 
All "diet" drinks contain it, being a primary constituent of Aspartame and other sweeteners. It's carcinogenic by inhalation.

I used it in a chemistry experiment once. If you combine it with an acid and reflux it for an hour or so, two molecules of phenylalanine combine to become the major component of DDT.
 
Sooo... basically it's not a good thing and especially not a good thing to be popping these throughout the day? For reference of the only example I can think of this can't be worse than smoking right? Thanks for the info.
 
Are you powdering the mint things and inhaling them?

Do you drink more than 10 gallons of diet soda a day?

If you answered "NO" to both of these questions, I'd say it's safe to eat the mints.
 
No to both, I figure it's regulated by the FDA probably so it has to be "safe". Thanks
 
Are photographs of space usually edited to make them look more appealing? For example I came across this photo and I was wondering how much editing it is likely to have recieved. This galaxy has a note saying it was a 150,000 light years away.

NGC2841cass50_schedler_c800.jpg


So if it is edited, what would the original have looked like?
 
Considering the Hubble telescope flies perfectly still without any vibration, and utilizes the best photographic equipment available, I doubt they enhance their photographs. Especially since enhanced photographs have no scientific value...

For reference, if the Hubble could stay focused on that same spot of dark space for 10 days without blurring it (for the Ultra Deep Field), then staying focused for the picture of a single galaxy should be easy.
 
They do actually enhance color in many space photographs in order to bring up the clarity a bit. Danoff could probably speak to this a little better.
 
I'm sure the detail has been modified but as Duke said the colour must surely be made to look more concentrated.

If that is the actual image taken, it makes it even more amazing.
 
Having watched the recent NASCAR Sprint and Nationwide races at Richmond... Why does fire spew out of their exhausts?

I'm aware that backfires occur in all sorts of racing - but I was under the impression that this was an unwanted effect, and which happens only for a moment while the revs suddenly jump? Yet during the race, almost every car's exhauast spewed flames throughout every turn...
 
I think it's to do with the fuel mixture - most race cars run very rich, which in turn contributes to unburnt fuel being passed out of the exhaust, ignited by the heat.
 
But then, wouldn't it be better to lean it out a bit more? Considering the constant 20-30cm flame in every turn, it's a bit of a waste, even if just a few litres in a 1400kg car, it might be that extra inch per second they were looking for...

And I wonder, aren't those flames a concern when going side-by-side into a turn? They're about 10 seconds long, and when concentrated on a tyre... :scared:
 
Especially in carburated engines, there is no fuel shut-off like you might get with an electronic injection system. If the engine's pulling vacuum, it's sucking gas down.

But yeah, some race engines are set rich, for cooling of all things. If you're old enough to remember Dan Gurney's IMSA Toyotas in the early '90s, they were 2-liter (maybe 2.2) turbo 4s, putting out enough power to dominate the GTP class. They were within nanobars of exploding, I mean right at the limit of boost. They had a very dark exhaust, almost like a diesel, they were running so rich. The rich mixture was cooler, and helped avoid detonation.

The above post appeared while I was typing, so I'll just add for emphasis, lean is hot. Maybe done-blowed-up hot.
 
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