Calculating the volume in closed container?

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Discussion Overview

The discussion revolves around calculating the volume of gas produced in a closed container following a chemical reaction. Participants explore the implications of pressure and temperature changes on volume calculations, considering the constraints of a closed system.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant describes a scenario involving a closed flask with an initial volume, pressure, and temperature, and seeks assistance in calculating the volume of gas produced from a reaction.
  • Another participant suggests calculating the volume of the flask minus the volume of any non-gaseous substances, noting the importance of the reaction's nature and the flask's rigidity.
  • A different participant emphasizes the need for a structured approach to the problem, suggesting the use of a homework template to clarify the information available.
  • One participant humorously comments on the small size of the flask, questioning the practicality of handling it.
  • A participant mentions consulting a professor who provided a specific formula for calculating the gas volume based on the reaction's parameters, indicating a potential method to solve the problem.
  • Another participant inquires about the contents of the flask before the gas was generated, suggesting that the method of producing gas (e.g., heating calcium carbonate) could influence the calculation.
  • Some participants express the need for more information about the reaction and the flask's characteristics to provide effective assistance.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach to calculate the gas volume, with multiple competing views and methods proposed. The discussion remains unresolved as participants seek further clarification and information.

Contextual Notes

The discussion highlights limitations related to the assumptions about the reaction and the flask's properties, which are not fully detailed. The specific nature of the reaction and the rigidity of the flask are noted as critical factors influencing the calculations.

takgt7
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Hi,
I have a hard time calculating volume in a closed container.
Let's say, I have a flask with a volume 0.125ml, which is closed, and the pressure inside is 16.87kPa with temperature 294.7k and I did some reaction to create a gas inside the flask. The new pressure in the flask is 87.19kPa and the temperature is now 296.4k. I want to find the volume of the gas this reaction made, but I have no idea how to do it.

I tried to use combined law (PV/T=PV/T), but since its a closed system, i doesn't work.
Please help!(;_;)
 
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Welcome to PF;
Volume of flask minus volume of non-gaseous stuff in it.
Care to be taken for porosity of reaction products.

A lot depends on the exact nature of the reaction, and how rigid the flask is.
 
Hello tgt, :welcome:

You want to order what you have available to solve this. (At the moment it's not a 'complete' problem). Perhaps the homework template helps:

Homework Statement

Homework Equations

The Attempt at a Solution



[/B]
[edit] I leave this to Simon.
 
takgt7 said:
Hi,
I have a hard time calculating volume in a closed container.
Let's say, I have a flask with a volume 0.125ml, which is closed, and the pressure inside is 16.87kPa with temperature 294.7k and I did some reaction to create a gas inside the flask. The new pressure in the flask is 87.19kPa and the temperature is now 296.4k. I want to find the volume of the gas this reaction made, but I have no idea how to do it.

I tried to use combined law (PV/T=PV/T), but since its a closed system, i doesn't work.
Please help!(;_;)
A flask with a volume of 0.125 mL is teeny tiny. Did you use tweezers to pick it up?
 
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Thanks for the replies.
I was thinking of using modified form of PV/T = PV/T but wasn't working.
I asked the prof and he said to use
V = mCaCO3 · %CaCO3 · R/MWCaCO3 x R/(Pf ′/Tf − Pi ′/Ti)
, which i believe was given but I wansn't aware of.
Now I can just put in the values I have and get the V!
P.S the flask was 0.125L ;)

Thanks for your help
best,
 
So what was in the flask before generating the gas? The gas produced will have the volume available in the flask. Seems that you have some calcium carbonate. What do you do to it? Heat is up to release CO2? Or you add some reactant (acid maybe).
 
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takgt7 said:
Thanks for the replies.
I was thinking of using modified form of PV/T = PV/T but wasn't working.
I asked the prof and he said to use
V = mCaCO3 · %CaCO3 · R/MWCaCO3 x R/(Pf ′/Tf − Pi ′/Ti)
, which i believe was given but I wansn't aware of.
Now I can just put in the values I have and get the V!
P.S the flask was 0.125L ;)

Thanks for your help
best,
We cannot help you unless you follow advise - you clearly have a specific problem in mind so please follow the advise in post #3.
Also remember: a lot depends on the exact nature of the reaction, and how rigid the flask is. This means that you have to supply that information.
 

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