ProbSet7_solutions(2)

# 01 ln 001 111 000 jk x 0095 0217 0046 111 kjk

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Unformatted text preview: r State B: W = 5!/2!3! = 10 Therefore, system A has greater multiplicity 18. A system has 100 000 molecules at energy level 1, 10 000 molecules at energy level 2, and 1 000 molecules at energy level 3. What is the entropy of the system? (hint: use the probabilistic definition) Answer: Total molecules = Nt =111 000 Probability of level 1 = N1/Nt = 100000/111000 = 0.90 Chem C130/MCB C100A. Fall 2010. Problem Set 7 UC Berkeley Page 12 Probability of level 2 = N2/Nt = 10000/111000 = 0.09 Probability of level 3 = N3/Nt = 1000/111000 = 0.01 Entropy = -Ntkb∑pilnpi = -111 000 J/K x ( 0.90 ln 0.90 + 0.09 ln 0.09 + 0.01 ln 0.01) = -111 000 J/K x (-0.095-0.217-0.046) = -111 kJ/K x (-0.359) = 39.849 kJ/K 19. A system at 293K with 100 000 molecules has two energy levels (A and B). At first, the two energy levels are populated equally. After a reversible process, energy level A is populated by 65% of the molecules. i) What is the change in entropy? ii) iii) How much heat was added or removed from the...
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## This note was uploaded on 01/27/2011 for the course MCB 100A taught by Professor Kuryian during the Spring '09 term at University of California, Berkeley.

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