Sapling Weeks 3+4 #14

[Madeline Ogden 3B]

Hi everyone, I am having trouble with number 14 on sapling and would really appreciate it if someone could help me out. I have attempted the problem several times and read through the feedback to no avail. For reference, this is the problem:
A sample of an ideal gas in a cylinder of volume 4.15 L at 298 K and 2.37 atm expands to 7.55 L by two different pathways. Path A is an isothermal, reversible expansion. Path B has two steps. In the first step, the gas is cooled at constant volume to 1.28 atm. In the second step, the gas is heated and allowed to expand against a constant external pressure of 1.28 atm until the final volume is 7.55 L. Calculate the work for path A and path B.
Thank you in advance!

[Chem_Mod]

For isothermal expansion use: w = - nRT ln V(final)/V(initial)

For now read the pages in the textbook on isothermal reversible expansion of an ideal gas in section 4A.3 (Expansion Work) and see detailed example 4A.2 (Calculating the work of isothermal expansion).

This will prepare you for class content.

[Asia Yamada 2B]

For Path A, since it’s an isothermal, reversible expansion, you would use the equation: w = -nRTln(V final/V initial). For the first step of path B, because the volume remains constant, there is no work done. In the second step of path B, you use the formula: w = -Pex•deltaV.

[kentbui1d]

I also had difficulty on this question. The reply really helped me out!

[SahajDole_1C]

I also had difficulty with this question!

[Natalie Do 3F]

Find your variables (so the original and final volumes) and use PV=nRT
For part B remember that when external pressure is constant, w=PdeltaV