Tagged Questions
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0answers
52 views
Air pressure in balloon
I have to calculate the air pressure inside of an hot air balloon. After some searching I found out that I can use the ideal gas law: PV = nRT (from Wikipedia)
So to get the pressure in the balloon I ...
1
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1answer
56 views
Calculating Air Density Lapse With Altitude (Specifically, pressures)
This might be a bit more of an engineering question, but I'm calculating air density drop-off with altitude, and I'm having some problems calculating the pressure (I'll run through my method). This ...
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2answers
79 views
Temperature change inside pressure chamber
Let's say there is a pressure chamber with some sort of sample / specimen (e.g. protein crystal) in it. Now I apply a certain amount of gas pressure, e.g. 10 or 20 atm. Let's say I use xenon as a gas. ...
3
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2answers
137 views
With ideal gases, varying quantity of moles, and having a constant volume how do temperature and pressure behave?
I'm trying to build a simulation of gases so I ended-up trying to use law of ideal gases ($PV = nRT$).
In my scenario:
volume is constant ($V=1\rm{m}^3$);
a known quantity of moles are being added ...
3
votes
1answer
91 views
Which heated, partially filled bottle will explode first?
This is in reference to a pasteurization discussion on a homebrewing forum.
I have four closed bottles which will explode if containing too much pressure. Two of them are 50% full (A and B), and two ...
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1answer
1k views
Ideal gas law, pressure increase and temperature
If I had a container, full with air, and I suddenly decreased the volume of the container, forcing the air into a smaller volume, will it be considered as compression, will it result in an increase in ...
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1answer
621 views
Calculate mass of air in a tyre from pressure
How can one calculate the mass of air inside a tyre, given a particular tyre size; a pressure, in $kPa = \frac{1000kg}{m\cdot s^2}$; and assuming room temperature, and normal air composition? I can't ...
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4answers
6k views
Why are volume and pressure inversely proportional to each other?
It makes sense, that if you have a balloon and press it down with your hands, the volume will decrease and the pressure will increase. This confirms Boyle's Law, $ pV=k=nRT $.
But what if the ...
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1answer
2k views
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3answers
651 views
When a gas expands against an external pressure of 0, must the stopper on the cylinder be massless?
Basically, I need to conceptually understand why the work a gas does is the integral of pressure external * dv and is 0 when pressure external is 0. I understand why dw = - p external * dv and so ...
