[Stoves] Pressure calculations

ajheggie at gmail.com ajheggie at gmail.com
Mon Jun 20 01:28:46 CDT 2011


On Monday 20 June 2011 00:48:50 Frank Shields wrote:

>
> Questions:
>
> 1)       Does the gases produced in (A) have the same volume as if in
> atmosphere?

Frank I need a picture to understand this but the answer is alsmost 
certainly no because the pressure in the bottle A is not atmospheric and 
will depend on whether the water levels are the same ouside and inside.
>
> 2)       If not, how is it calculated and what would the volume be at
> open atmosphere?

Thapt's simple 

P1V1=P2V2 at the same temperature and P2 is atmospheric, you iknow the 
volume of the container A.
>
> 3)       Is there a difference in pressure required to fill (A) with
> methane if the tube goes all the way to the inside top (into the
> methane gas) of (A) or is it the same as if just going several cm up
> into the bottle?

Again this depends but it looks like initially the water is pulling a 
depression in A until the water levels inside and outside A are the same.
>
> 4)       Is there a change in methane pressure as (A) fills with gas?

I think so in your set up, if A is allowed to float, like a gasometer the 
pressure is slightly above atmospheric and depends on the weaight of A, 
it only varies slightly as A fills up as the gas supports more of its 
weight (NB all of the weight of the top is supported all of the time in 
this scenario.
>
> 5)       Does the height of (A) relative to (C) change anything
> regarding gas pressure in (A)?

It depends on the various water levels.
>
>
>
> I would like to know the calculations as I find I have no idea where to
> start.

Search on Charles Law and Boyles law plus Avogadro

I suspect Steve Taylor can answer this better than I.

AJH




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