Mathematical challenge wrt diving

[Mad Scientist]

My issue with arbitrarily choosing to make n variable is that there is no justification for choosing that particular value as your additional variable. If you choose to discard the assumption that the problem is constant in both V and n, why is it that you have chosen to have V remain a constant? Without explaining that, you cannot claim to be showing true understanding of what you are doing.

Kinetics of an explosion in a confined space using the ideal gas law to describe the event defines that volume must remain constant. PV=nRT changes to P=knT, and n will always increase due to many smaller molecules being made from one big one.

 

[ClayJar]

Okay, so you're assuming it was a chemical explosion and that there was no deformation of the chamber. What if the "explosion" was the sudden expansion of gases superheated by an intense pulse of laser light? What if that superheating converts some nitrogen and oxygen into nitrogen oxides?

n O₂ + m N₂ --> x NO + y NO₂ + z N₂O + ...

So, in the case of an "explosion" in an oxygen/nitrogen atmosphere created without an explosive chemical, n can only *decrease*. So, you're going to assume that there had to be a chemical explosive in the chamber and that the chamber held without any deformation? If you're going that far, why do you even bother throwing the ideal gas law into it? You're already throwing out the problem definition for a fancifully creative alternative, why limit yourself to ideal gas laws?

Frankly, your entertainingly conceived problem about a chemical explosive being set off inside a recompression chamber would be fun to solve. Would you like to actually write it up?

(A sample of 10 grams of trinitrotoluene is detonated in an otherwise empty chamber. Before detonation, the remaining volume of the chamber contained a gas mixture of 21.000% O₂ and 79.000% N₂, and the internal gauge pressure is 10.1325 kPa. The ambient pressure is 101.325 kPa. The chamber is made up of a cylindrical body and hemispherical ends, both with a diameter of 1.5000 meters. The cylindrical portion of the chamber is 2.5000 meters long...)

Let me know when it's done. Be sure to specify the reaction products, otherwise I'll just have to say it's unsolvable and completely miss the point. (Meanwhile, if anyone has any more of these simple problems, we'll do those.)

 

[Mad Scientist]

Okay, so you're assuming it was a chemical explosion and that there was no deformation of the chamber. What if the "explosion" was the sudden expansion of gases superheated by an intense pulse of laser light? What if that superheating converts some nitrogen and oxygen into nitrogen oxides?

So why dont you share your definition of an explosion with us?

 

[ClayJar]

So why dont you share your definition of an explosion with us?

Why don't I? I don't share it because I consider it irrelevant, and while I have done far more than was likely required in the name of reasonable discourse, I simply refuse to get into a pointless debate over the semantics of a question whose wording was in no way subject to such precision when it was conceived.

Such a discussion would be a verbal example of "false precision". It would be as if I said I used 2473psi from my tank on the last dive. My SPG does not give me that precision, and therefore, any implicit or explicit claim to the contrary that I may make is in error. As I'm certain that any man of science should be implicitly familiar with this concept, I will leave it at that.

 

[Gary D.]

Something I learned a long time ago was DO NOT have or pass gas in a chamber.

Depending on ones diet and severity of the discharge it could take several vents to return the chamber to normal. The pressure increase and temperature rise would be regulated by ones diet. That is if the other occupants don’t pound the crap out of you which creates another HazMat odor problem.

Now should that gas ignite, causing an explosion or something along that line, the occupants might be reduced to hairless, over tanned, nudies fresh out of the Bar-B-Q.

In any case make sure it’s on video.

Gary D.

 

[Jonas Isaksen]

Application of the universal gas law

An explosion occurs in a hyperbaric chamber that is at a depth of 100 FSW. If the ambient temperature in the chamber before the explosion was 72 degrees F, and the pressure gauge on the outsideber shows that the chamber pressure immediately increased to 650 FSW. How high did the temperature rise in the chamber?

The book's only answer is:
Using the universal gas law, one can determine that the temperature rose to almost 750 degrees F.

According to the author the pressure rise to 350 FSW, not 650 FSW, which will iaw my calculations give a temperature of 759,5 deg C, not as written 750 deg F which is another typing error.