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Topic: vaporization problem  (Read 11349 times)

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Offline Nanothree

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vaporization problem
« on: July 14, 2007, 09:09:50 PM »
 ???  I'm new to vaporization. I've been reading about it and am trying to work some problems.

Here's the one I can't figure out. Like, I know Delta Hvap = Hvap - Hliquid, and I see that some sort of PV=nRT calculation is required here, but where do I start?

The enthalpy of vaporization of benzene, C6H6(l), is 33.9 kJ mol-1 at 298K. How many liters of C6H6(g), measured at 298 K and 95.1 mmHg, are formed when 1.54 kJ of heat is absorbed by C6H6(l) at a constant temperature of 298K?


I'm having difficulty figuring out what's happening conceptually there. C6H6(l) is absorbing heat to form a vapor, but volume and moles are unknown. How do I go about approaching these kinds of problems?


Offline Nanothree

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Re: vaporization problem
« Reply #1 on: July 14, 2007, 10:16:18 PM »
Nevermind!! I solved it!!!!!   8)


For those curious:

(1.54 kJ) * (1 mol / 33.9 kJ) = 0.0454 mol C6H6 (g)

v=(nrt)/p
   = (.0454) (0.0821) (298) / (95.1/760)
   = 8.88 L


Offline generalsky

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Re: vaporization problem
« Reply #2 on: July 15, 2007, 12:20:04 AM »
Yeah, I agree with the former result. How to say ,in this kind of calculation, we should be careful with the units of every quantity.

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