(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

4. An inventor would like to patent a thermodynamic device and is making

the following claims:

The device can accept a stream of gas and split it into a hot and cold jet of

the same gas. This device is said to contain no moving parts, consumables, or

power supply and it is claimed to operate in different modes such that it can:

A. accept an ideal gas (e.g. argon) at 4 atm, 20 ◦ C, 2 mol/min and output

one stream of 1 mol/min at 1atm, T=-20 ◦ C and, simultaneously, a second

stream at 1 mol/min, 1atm, T=60 ◦ C

B. accept an ideal gas at 4 atm, 20 ◦ C, 2 mol/min and output one stream

of 1.5 mol/min at 1atm, T=0 ◦ C and, simultaneously, a second stream at

0.5 mol/min, 1atm, T=90 ◦ C

C. accept an ideal gas at 1.1 atm, 20 ◦ C, 2 mol/min and output one stream

of 1.6 mol/min at 1atm, T=-30 ◦ C and, simultaneously, a second stream

at 0.4 mol/min, 1atm, T=220 ◦ C

Which of these claims would you reject? Which ones would you accept and

why?

2. Relevant equations

Ideal gas law: [tex]PV = Nk_{B}T = nRT [/tex]

Where n= N/Na

3. The attempt at a solution

My first thought was to try and think of a quantity that should remain constant through the process, so that I could calculate it for the initial conditions and for the products and compare.

As the question says there is no power source, fuel etc I would assume that there is no external heat being input into the system and thus it's an adiabatic process. So I tried calculating

[tex] P^{1-\gamma}T^{\gamma} = constant [/tex]

Where for a monatomic ideal gas (such as Argon) [tex]\gamma=\frac{5}{3}[/tex]

However, this plan didn't work out. The values were difficult for A,B and C and I'm sure at least one of the options should be accurate.

Can anyone tell me the flaw in my logic and perhaps point me in the right direction.

Thanks

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Thermodynamics: Ideal gas splitting invention problem

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