NS FL #5 Chem/Phys Q40

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sdaswani
Posts: 26
Joined: Sat Jan 26, 2019 5:32 pm

NS FL #5 Chem/Phys Q40

Post by sdaswani » Tue Mar 12, 2019 8:31 am

why is the answer here evaporation and not condensation? From my understanding, if the latent heat is decreasing at the ocean (heat energy is given off to the environment), isn't this condensation? evaporation would imply the ocean absorbing (not releasing heat energy) and turning into water vapor. given this, the entropy of the ocean would decrease too, which matches the Qs stem. Would appreciate any clarification! thanks!!
NS_Tutor_Will
Posts: 417
Joined: Fri May 25, 2018 9:15 am

Re: NS FL #5 Chem/Phys Q40

Post by NS_Tutor_Will » Tue Mar 12, 2019 8:50 am

The basic idea here is that we're trying to lower the entropy and the energy of the ocean. Evaporation is a process that meets both of these criteria. Evaporation means that molecules in the liquid phase are escaping the liquid and becoming gas particles. This of course increases entropy, since a gas has much higher entropy than a liquid. Similarly, energy in the liquid will be lost because the highest energy molecules (those with the most KE) are the ones that escape from the liquid. Thus, the average KE of the liquid molecules decreases each time a high-energy molecule evaporates and joins the gas phase.

Condensation is the opposite process; it would increase the energy of the liquid phase.

I hope this helps!
sdaswani
Posts: 26
Joined: Sat Jan 26, 2019 5:32 pm

Re: NS FL #5 Chem/Phys Q40

Post by sdaswani » Sat Mar 16, 2019 4:02 pm

Thanks!!
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