# What is the temperature at the end of the process ?

• alireza83
In summary, the conversation is about a problem involving 10 grams of oxygen gas undergoing various processes and the questions that arise from it. The initial pressure, temperature, and volume are given, and the final pressure for the first process is halved. The first question asks for the temperature at the end of the process, while the second, third, and fourth questions pertain to the amount of work done in each step. The final process involves an isobaric expansion to the original volume, and the final question asks for the work done in this step. The conversation also includes discussions on how to solve for the temperature and work using the given equations. Part C remains unsolved as the initial volume is not given.

#### alireza83

I need help guys. I don't have any idea what to do for this question

10 grams of oxygen gas at an initial pressure of 2.5 atm. and a temperature of 25 C
undergoes an isochoric cooling until the pressure is halved.

(a). What is the temperature at the end of the process?
(b). How much work has been done in this step? Next, the gas is isothermally compressed to its original pressure.
(c). What is the volume at the end of the compression?
(d). How much work has been done in this step? Finally, the gas undergoes an isobaric expansion to its original volume.
(e). How much work has been done in this step?ne in this step?

If you know

$$\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}$$

and the volume is the same, then I think you can find T2. The final pressure P2 is half of the initial pressure P1

^^^^Exactly, so here's how you set it up (hope this helps)

T2 = ( P2 / P1 ) * T1

*Don't forget to convert to Kelvins during the calculations and remember to subtract 273 afterwards. For Part B, my question to you is : Is any Work done during a Isochoric process?

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I'm not sure how you tackle part c as the volume isn't given initially in the problem.

I'm assuming you use : P1V1 = P2V2 & Work = -nRT*ln(Vf/Vi)

^^Any Ideas on how to solve part C?

But in order to solve for the work, you need the number of moles in the 10 grams of Oxygen Gas (O2), and you need the Final & Initial Volume.