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Topic: enthalpy, heat, work  (Read 7925 times)

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Offline BreakingBad20

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enthalpy, heat, work
« on: May 08, 2011, 08:07:52 AM »
A fluorocarbon liquid has a standard enthalpy of vaporization of 32 kJ/mol. Calculate q (heat), w (work), ΔH (enthalpy change) and ΔU (internal energy change) when 2,50 mol are vaporized at 250 K and 750 torr.

dHvap = 32kJ/mol
q = 32kJ/mol x 2.5 mol
q = 80kJ

pV = nRT
(750 x 133)V = (2.5)(8.31451)(250)
V= .0521 J/Pa

w = pex x dV
w = (750 x 133)Pa x .0521 J/Pa
w = 5196.975 J

dU = w + q
dU = 5196.975 + 80000
dU = 85196.975 J

dH = dU + pV
dH = 85196.975 + 5196.975
dH = 90393.95 J

Would you agree with the following calculations or am I going wrong somewhere in regards to understanding the theory?
All feedback is appreciated because I have my exam on the 14th of May and between work and other exams I am struggling to grasp the full understanding!

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