## ΔS=q/t

$\Delta S = \frac{q_{rev}}{T}$

Tamera Scott 1G
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Joined: Fri Sep 28, 2018 12:27 am

### ΔS=q/t

When looking at the equation ΔS=q/t, could we say that ΔS=nΔH/T as well?

Nicole Lee 4E
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### Re: ΔS=q/t

ΔS=ΔH/T at constant pressure and temperature.

haleyervin7
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Joined: Fri Sep 28, 2018 12:15 am

### Re: ΔS=q/t

What are the requirements to be able to use q/T? Just constant temp?

Posts: 65
Joined: Fri Sep 28, 2018 12:17 am

### Re: ΔS=q/t

you can use it when t is constant and you can use deltaS=DeltaH/T when pressure is constant

ran2000
Posts: 66
Joined: Fri Sep 28, 2018 12:15 am

### Re: ΔS=q/t

This can only be said when pressure is constant since q(at constant pressure)= delta H

Nicholas Le 4H
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Joined: Fri Sep 28, 2018 12:24 am

### Re: ΔS=q/t

Yes, you can use this when pressure is constant since the change in enthalpy is equal to q when pressure is constant.

Soumya Ravichandran 4H
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### Re: ΔS=q/t

Why can you only calculate delta S, when the q for the reaction is reversible?

Dayna Pham 1I
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### Re: ΔS=q/t

Soumya Ravichandran 4H wrote:Why can you only calculate delta S, when the q for the reaction is reversible?

The reaction does not have to be reversible in order to calculate delta S in this way. They just use q rev as a convention, but since delta S is a state function, the pathway doesn’t matter (therefore, it doesn’t matter if it’s reversible or reversible). The only thing we look at is final - initial. Which would be the same for irreversible and reversible.

Ashe Chen 2C
Posts: 31
Joined: Mon Jan 07, 2019 8:23 am

### Re: ΔS=q/t

when pressure and temperature are constant, $\Delta S = \Delta Hsys/T$