[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]

If you know the internal volume of the tank, you can calculate to moles

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

[zubinarmase]

Get many ideas from different people and places and also from the internet, I will update once I found the solution, Thank you guys for your help