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Topic: A strange question.  (Read 4555 times)

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Offline Zammo

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A strange question.
« on: May 22, 2007, 02:29:59 PM »
Forgive the question but I have been wondering about this for some time. Yes this question is quite hypothetical but please bare with me.

In the film Aliens the creatures they fight are said to be a carbon based life form with concentrated acid for blood. In many parts of the film we see them being shot with standard bullets and their acid blood spurting out and some occasions injuring and killing the people shooting at them.

My question is what would happen to acid if a large quantity of flame was added to it. In terms of the film what would have happened to one of the Aliens if someone shot it with a flame thrower? Would the acid still be a potentially harmful liquid form or would heating it to extreme temperature change the chemical structure of it in any way?


Thanks.


Offline Borek

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Re: A strange question.
« Reply #1 on: May 22, 2007, 02:55:24 PM »
It doesn't depend on the chemistry, but on the screenwriter imagination :)

Besides, flamethrowers were used in Alien II. imdb.com:

Quote
Ripley: Lieutenant, what do those pulse rifles fire?
Gorman: 10 millimeter explosive tip caseless. Standard light armor piercing rounds, why?
Ripley: Well, look where your team is. They're right under the primary heat exchangers.
Gorman: So?
Ripley: So, if they fire their weapons in there, won't they rupture the cooling system?
Burke: [interjecting] Woah woah. Yeah, she's absolutely right.
Gorman: [turns round to Burke] So, so what?
Burke: Look, this whole station is basically a big fusion reactor...
[Gorman turns back to stare, horrified, at the screen]
Burke: ...right? So you're talkin' about a thermonuclear explosion and "AdiĆ³s, muchachos."
Gorman: Oh, great. Wonderful. s#*$!
(...)
Gorman: Apone! Look... we can't have any firing in there. I, uh... I want you to collect magazines from everybody.
Hudson: Is he fuckin' crazy?
Frost: What the hell are we supposed to use man? Harsh language?

So, they used flamethrowers :)
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Offline Zammo

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Re: A strange question.
« Reply #2 on: May 23, 2007, 07:17:38 AM »
I know they used them, they just didn't actually ever fire one close up to an alien.

I was just wondering if scientifically heating up acid to an extreme temperature would alter it?


Offline enahs

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Re: A strange question.
« Reply #3 on: May 24, 2007, 03:35:40 PM »
Heating anything up to an extreme temperature will alter it some how. However, that "extreme temperature" is variable and subjective, depending on the substance.


However, your biggest problem here is that you want to believe it is possible for a "carbon based life form" to have such concentrated acid for blood that it can "melt" through 2 feet of re-enforced metal in a matter of minutes but be great for a life system.

Also, it depend on what kind of acid they (the writers) wish to say they used. There are 2 main categories  of acids, Lewis Acids and Bronsted Acids.

The traditional acid, Bronsted Acids (virtually every chemical reaction can be considered a Lewis Acid-Base reaction). Anyway. These typical "Bronsted acids" (donation of a H+ ion) occur in solution, typically water. Due to the auto-ionization of water (water is both an acid and base) there is a limit on how concentrated a acid can be, in water. And while I am not to up on industrial chemicals, I am pretty sure there is no typical acid in solution that can eat through a couple of feet of re-enforced metal in such a short time. There are some acids that probably could, but they would most likely be gases, I believe.

And so, what do you get when you heat water up (since most typically acids, the only acid these genius movie writers know of)? Steam.


So, you can do a home experiment. Vinegar is a acid, a typical acid in solution. When you introduce it to extreme heat and it boils, what happens. What are you left with? Is it still an acid? Are the majority of typical Bronsted acids even acids unless they are in solution?


And so to truly answer your question, do not try and apply real science and logic into trying to understand what happens in movies, as it is virtually never real science and logic.


Offline sjb

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Re: A strange question.
« Reply #4 on: May 25, 2007, 03:04:50 AM »
I was just wondering if scientifically heating up acid to an extreme temperature would alter it?

Probably not quite what you mean, but certainly heating beta-keto acids or simlar can decarboxylate them - look at malonate chemistry etc...

S

Offline organoman

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Re: A strange question.
« Reply #5 on: June 13, 2007, 04:56:52 AM »
If question is about behavior of general mineral acid at elevated temp... let me tell u most of the mineral acids are gases dissolved in water such as hidrochloric acid is hydrogen chloride in water in water or sulfuric acid id sulfur trichloride plus water. So increasing the temperature should decrease the solubility of these gases in water and gases should be evaporated leaving water.
This actually hapen so.Solubility of HCL gas in water is about 35% at 25 deg C. So if you heat it you will find HCL gasesx escaping. But if this heating is slow it actually increases the activity of acid as lowering the conc increases the activity. However heating some acid at a supercritical temperature  at atmospheric temperature should evaporate everything even water and nothing left behind.
In short what they show in movies are beyond logic and science and only imaginations and wishes of makers.

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