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Delta S equations
Posted: Wed Feb 13, 2019 12:20 pm
by Katherine Grillo 1B
I'm confused about the different delta S equations. When does delta S equal q/t vs nRln(V2/V1) vs nCln(T2/T1)?
Re: Delta S equations
Posted: Wed Feb 13, 2019 12:29 pm
by MaanasO 1A
Hi Katherine!
dS = q/t when you're dealing with a reversible process. dS = nRln(Vf/Vi) when the process is isothermal. dS = nCln(Tf/Ti) when there's a change in temperature associated with the change in entropy. Your C value will change based on whether your volume (Cv) or pressure (Cp) are constant.
Hope that helps!
Re: Delta S equations
Posted: Wed Feb 13, 2019 12:51 pm
by 705192887
MaanasO 1A wrote:Hi Katherine!
dS = q/t when you're dealing with a reversible process. dS = nRln(Vf/Vi) when the process is isothermal. dS = nCln(Tf/Ti) when there's a change in temperature associated with the change in entropy. Your C value will change based on whether your volume (Cv) or pressure (Cp) are constant.
Hope that helps!
In the last sentence you said the C value will change depending on whether volume or pressure are constant. Could you elaborate on that?
Re: Delta S equations
Posted: Wed Feb 13, 2019 1:06 pm
by Zenita Leang 2K
If you have a constant volume then you will use C
v which is equivalent to
R. If it has a constant pressure, then you will use C
p which is equivalent to
R. R is the constant on the constants and equations sheet.