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Post by electrovir on Dec 7, 2011 14:55:37 GMT 10
Any of you guys chemistry studs that would be able to help me with this?
"Supposed that 50.0 g of H2O(L) at 20.0°C is mixed with 65.0 g of H20(L) at 50.0°C at constant atmosphereic pressure in a thermally insulated vessel. Calculate ∆S and ∆Stot for the process."
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Post by liltom1993 on Dec 7, 2011 14:58:10 GMT 10
Write it in equation form, I studied it for a year.
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Post by liltom1993 on Dec 7, 2011 15:00:20 GMT 10
What does the triangle thing and S stand for ?
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Post by electrovir on Dec 7, 2011 15:02:17 GMT 10
Er… H20(L) -> H20(L) lol… the only thing that changes is the temperature.
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Post by electrovir on Dec 7, 2011 15:04:32 GMT 10
∆ is "delta" and means change. S is entropy, defined as ∆H/T (change in enthalpy/temperature). The problem is that my books have the enthalpy for substances at 25°C, not what they're at.
(BTW, if my calculations are correct when the two mix the final temperature is about 36°C, is that correct?)
EDIT: Entropy can also be defined as Q(in a reversible process)/T, and Q is, when in a process with constant pressure, nCp∆T. However, when I plug in those numbers the answer isn't correct T_T
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Post by liltom1993 on Dec 7, 2011 15:15:49 GMT 10
The combined substances should come to around 35-36 yes, but sorry, I have no clue what how to work out anything to do with thermodynamics. D:
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Post by electrovir on Dec 7, 2011 15:18:58 GMT 10
Thank goodness I'm going into engineering… (and not chemical).
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