physics question

[mikemill]

Okay, now that we have covered Boyle's Law, we can move on.

If my flexible container holding 7L of gas at 25 fsw is cooled from 85 degrees F to 40 degrees F, what will the new volume be?

How flexible is the container? What's the gas?

Assuming an ideal gas and a container that provides no resistance (and no change in pressure):
V₂ = (V₁ * T₂) / T₁

T₁ = 85 F = 302.594444 K (Conversion)
T₂ = 40 F = 277.594444 K

V₂ = (7L * 277.594444 K) / (302.594444 K
V₂ = 6.421668165 L

 

[Mike Boswell]

How flexible is the container? What's the gas?

Assuming an ideal gas and a container that provides no resistance (and no change in pressure):
V₂ = (V₁ * T₂) / T₁

T₁ = 85 F = 302.594444 K (Conversion)
T₂ = 40 F = 277.594444 K

V₂ = (7L * 277.594444 K) / (302.594444 K
V₂ = 6.421668165 L

YOU ARE CORRECT, SIR!

V1/T1 = V2/T2

Anybody know whose "law" this is?

 

[SC_Hoaty]

Anybody know whose "law" this is?

Charles Law, named after Jacques Charles.

I'll take Famous Dead Horses for $100, Alex.

 

[mikemill]

YOU ARE CORRECT, SIR!

V1/T1 = V2/T2

Anybody know whose "law" this is?

Charles Law, named after Jacques Charles.

I'll take Famous Dead Horses for $100, Alex.

To be honest I don't remember which one is which. Once they were combined it seems pointless (to me) to remember them individually. I just remember ideal gas law and how to remove the variables I don't need.

 

[SC_Hoaty]

To be honest I don't remember which one is which. Once they were combined it seems pointless (to me) to remember them individually. I just remember ideal gas law and how to remove the variables I don't need.

 

[Thalassamania]

Volume/Temperature is Charles' Law.

Pressure/Temperature is Gay-Lussac's Law.

 

[Mike Boswell]

Pressure/Temperature is Gay-Lussac's Law.

Sacre Bleu, Thal, are you French? P/T is Boyle's Law. All the English say so! But seriously, Wikipedia says it is Amonton's Law, not Gay-Lussac's.

Anyhow, to round off the basic physics we have Dalton's Law. But many divers don't really know what it is, or how it applies.

 

[mikemill]

Pressure/Temperature is Gay-Lussac's Law.

Sacre Bleu, Thal, are you French? P/T is Boyle's Law. All the English say so!

Anyhow, to round off the basic physics we have Dalton's Law. But many divers don't really know what it is, or how it applies.

According to Wikipedia Boyle's Law is P/V
P/V: Boyle's law - Wikipedia, the free encyclopedia
P/T: Gay-Lussac's law - Wikipedia, the free encyclopedia
V/T: Charles's law - Wikipedia, the free encyclopedia

Combine them and you get: Combined gas law - Wikipedia, the free encyclopedia
Throw in Avogadro's law - Wikipedia, the free encyclopedia and you get Ideal gas law - Wikipedia, the free encyclopedia

So we've got 4 different (I'm excluding combo ones) laws to remember. Or we can remember the one that combines it all together. I choose to remember the one.

 

[Mike Boswell]

Wikipedia also says that attributing P/T=K to Gay-Lussac is erroneous, and that it properly should be called Amonton's Law.

Don't forget Dalton's Law.

And then, there is Henry's Law....

 

[mikemill]

Wikipedia also says that attributing P/T=K to Gay-Lussac ie erroneous, and that it properly should be called Amonton's Law.

Yeah, but science and math isn't always fair when it comes to naming. Kinda like how Newton's method - Wikipedia, the free encyclopedia is the common name but it really is Newton–Raphson method. According to Raphson's wiki page his version (and not Newton's) is actually the one taught today. How's that for justice?