Practice midterm #4

[Alyssa Pelak 1J]

Can someone please explain how we calculate work and heat for question 4 on the practice midterm?

The question reads, "You have a system consisting of 0.60 moles of an ideal gas contained in a 50.0L 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 20.0L. Then, you pressurize the system to 8.0 atm using an isochoric method. Finally, you perform a reversible, isothermal expansion (now at 1015.5 K) on your system back to a 50.0L 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."

Thank you!

[Chem_Mod]

As discussed in the review session, there are 3 steps that occur and you must calculate the work for each step and add them up. We know that q=-w because the internal energy of the system does not change (initial state=final state). Break it up into 3 steps to find work. For further clarification, feel free to drop into Hedrick room 125 tomorrow, 2/12, where I will be covering for Michael's UA session. -Lyndon