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CO2 Liquid relation with Gas

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zubinarmase:

Hello,
I have a doubt about quemistry that I could not do properly the maths that I want.

I work in a company and they have 100% CO2 in a huge gas tank, for welding, 15 bar, -30 degrees.
My company, pays to the company to fill the tank 250 €/TON of CO2, liquid.
But, when the welders do their job, they spent 8 l/minute (gas).

How can i get the properly the money that I spent in imagine 15 minutes of work.

Could you help me?

Meter:
If you assume CO2 to be an ideal gas, you can use the ideal gas law.

Edit: Never mind, I misread the question.

Borek:
Hard to tell exactly not knowing what is the temperature of the gas used. Assuming it is delivered at 8 Lpm at room temperature it is - as Meter wrote - just a trivial application of ideal gas law followed by also a trivial conversion of moles to mas.

Looks to me like a question form the "dimensional analysis" section of a HS book.

Meter:

From: https://www.researchgate.net/figure/A-phase-diagram-for-CO2_fig1_267328310

So at -30 oC and 15 atm (~1.5 MPa) CO2 is definitely in its liquid phase. If you know the internal volume of the tank, you can calculate to moles. Then 8 l/min would be easy to calculate if you know the pressure of the gas upon expulsion.

Borek:

--- Quote from: Meter on May 21, 2022, 08:10:13 AM ---If you know the internal volume of the tank, you can calculate to moles
--- End quote ---

My understanding is that OP has the price per mass, so there is no need to know the amount in the tank.