Lyndon Review Questions #6


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BNgo_2L
Posts: 95
Joined: Wed Sep 11, 2019 12:17 am

Lyndon Review Questions #6

Postby BNgo_2L » Mon Feb 10, 2020 9:27 pm

You have a system consisting of 0.40 moles of an ideal gas contained in a 100.0L container at
1.0 atm. You just love chemistry to a fault, so you perform a series of steps to the system. First,
you perform an isobaric compression of the container to 10.0L. Then, you pressurize the system
to 10.0 atm using an isochoric method. Finally, you perform a reversible, isothermal expansion
on your system back to a 100.0L volume at 1.0 atm. Now, to apply your knowledge, you must
calculate ∆U, q, w, and ∆S of the system specifically over the entire process. Much fun!

I know that we use q = -w, but which equation would we use to calculate work? w = -nRTln(v2/V1) requires the temperature, but we're not given it, so how would we solve this?

Ryan Lee 1E
Posts: 50
Joined: Sat Aug 17, 2019 12:16 am

Re: Lyndon Review Questions #6

Postby Ryan Lee 1E » Mon Feb 10, 2020 9:39 pm

In this question, you'll need to split the q and w into three separate sections. First the isobaric compression, then the isochoric pressurization, then the isothermal expansion. You can calculate q or w for all of these, which means if you sum the q of all of them, then you'll also know what the w is. For the first two steps, you can use q = ncdeltaT where you relate the T to PV=nRT and T = PV/nR since you know what PV and nR is.

Rita Chen 1B
Posts: 112
Joined: Sat Jul 20, 2019 12:15 am

Re: Lyndon Review Questions #6

Postby Rita Chen 1B » Wed Feb 12, 2020 9:15 am

In the question, how would you approach it? What would you try to solve for first?


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