How Do You Calculate Entropy Changes in Thermodynamics?

[rafaela.nita]

Thermodynamics for P Chem NEEd HELP By tomorrow!

Homework Statement

What are the values of the entropy changes (system, surroundings, and universe) for the cooling of 1 mol of O2 (g) from 298 K to O2 (l) at 90.19 K if the process is done

a. Reversibly
b. Irreversibly

by placing the sample in liquid hydrogen at 13.96 K? Assume enthalpy change of vaporization is 6820 j/mol at 90.19 K and Cp = 7/2 R for the gas.

Homework Equations

How do you solve this problem for all types of entropy?(entropy changes (system, surroundings, and universe)

The Attempt at a Solution

Have no clue how to start it. Please help!

 

[turbo]

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