Heating Curve


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Porus_Karwa_2E
Posts: 72
Joined: Fri Sep 28, 2018 12:24 am

Heating Curve

Postby Porus_Karwa_2E » Tue Feb 12, 2019 1:43 pm

Can someone please explain how to calculate the entropy through different phase changes using the heating curve as a guide?
Thanks!

Seohyun Park 1L
Posts: 73
Joined: Fri Sep 28, 2018 12:29 am

Re: Heating Curve

Postby Seohyun Park 1L » Tue Feb 12, 2019 2:09 pm

Entropy change through heating curve is similar to that of calculating enthalpy change. For phase changes, you would use Delta S= qrev/T as temperature is constant. You can calculate qrev using the enthalpy of fusion/vaporization/whatever situation is. For temperature changes, you would use Delta S= nClnT2/T1, with C being the heat capacity (either constant volume/pressure depending on the situation) of that state.

Charles Gu 1D
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

Re: Heating Curve

Postby Charles Gu 1D » Sat Feb 16, 2019 11:57 am

you would need to add the phase change and then the how much entropy it took to raise the temperature. so Delta s = q/t + Delta s= nCln(T2/T1). Don't forget to change temperature to kelvin.

Diana Bibireata 1B
Posts: 60
Joined: Fri Sep 28, 2018 12:23 am

Re: Heating Curve

Postby Diana Bibireata 1B » Sun Feb 17, 2019 2:33 pm

When there is a phase change you use the equation S = qrev/T because the temperature is constant. You use S = nClnT2/T1 when the temperature does change.


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