Entropy when relating to a single atom

[Jonathon Jauregui]

I was always confused on the topic when relating the C value for a reversible/isothermal entropy calculation where either under constant volume or pressure. How do I know when to use those values (3/2R) (5/2R) I was just confused when it was brought up in the textbook. Like when do I use it when relating it to a reaction?

[Stephanie_manasyan]

Hi there! These values help for when pressure or volume are constant. So essentially, you would use the 5/2 when pressure is constant, and you use 3/2 when volume is constant to calculate of rC so that you can then calculate for heat capacity or work. Hope this helps!