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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: smoothsilkmusic on November 04, 2007, 04:05:27 AM

Title: Work and Phase Change
Post by: smoothsilkmusic on November 04, 2007, 04:05:27 AM
H2O (g) --> H2O (l)

What are the signs of q and w in the equation E = q + w?

q is negative, but I've asked two physics teachers, and they gave two different answers for work--one said positive and one said negative. The answer key said positive, but my chemistry teacher said he'll give credit if we can show that work is negative as well. Can anyone help?
Title: Re: Work and Phase Change
Post by: Yggdrasil on November 04, 2007, 11:40:31 AM
Remember that w = -pΔV.  How does the volume of one mole of water vapor compare with the volume of one mole of liquid water?