problem_set_08

# problem_set_08 - volume. Make the “equal-area”...

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1 Problem Set 8 Chem 110A F09 1. Consider the 298K isothermal reversible expansion of a mole of monatomic van der Waals gas – Xenon – from 1.0 L to 100. L. How much work is done, and how much of this work is associated with the attractions between molecules in the gas? How much would the work have been if the gas behaved ideally? 2. Suppose this same sample undergoes instead an adiabatic irreversible expansion against zero external pressure, from the same initial state (T=298K and V=1.0L) as in problem 1 above, and to the same final volume. What is the final temperature of the sample? What would it have been if the gas behaved ideally? 3. Show that RT ( V m b ) 2 2 a V m 3  RT V m 2 as b V m 0 ( i . e ., V m  ) . 4. Calculate the van der Waals isotherm for H 2 O at 298K, i.e., plot its pressure as a function of molar
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Unformatted text preview: volume. Make the “equal-area” (“Maxwell”) construction, graphically/manually (e.g., “by eye”), and estimate in this way the equilibrium vapor pressure of water at room temperature. How does it compare with the tabulated value for P vap H 2 O (298 K ) ? 5. Estimate the van der Waals b coefficient (as a volume per mole) for your favorite substance. HINT: assign a “hard-core”, impenetrable, volume to your molecule, in cubic Angstroms – this corresponds roughly to the size of the electron charge cloud – and then multiply by Avogadro’s number. How does your estimate compared with the tabulated value? 6. Show that (these are…”derivations”!) P 1 P ( ln z / P ) T and T 1 ( ln z / T ) P ....
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## This note was uploaded on 04/17/2011 for the course CHEM 110A taught by Professor Schwartz during the Spring '06 term at UCLA.

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