ProbSet7_solutions(2)

# Which of state a or state b has more internal energy

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Unformatted text preview: n 5 = 1.6 J/K; energetic = kb ln 120 = 4.8 J/K total entropy = positional + energetic entropy = 1.6+4.8 = 6.4 J/K 15. A system with one mole of an ideal gas changes its volume from 10L to 1L by compression. What is the change in entropy? Answer: ∆S = nR ln (V2/V1) = 1mol x 8.31 J/Kmol x ln (1L/10L) = -19.13 J/K Chem C130/MCB C100A. Fall 2010. Problem Set 7 UC Berkeley Page 11 16. Consider this system with five molecules and three energy levels. The energy levels are such that a molecule at energy level 1 contributes 1J of energy to Utotal, a molecule at energy level 2 contributes 2J of energy to Utotal. Which of state A or state B has more internal energy? State A State B Answer: For State A: Utotal = ∑NiUi = 3xN3+2xN2+1xN1 =3x1+2x3+1x1 = 10 For State B Utotal = ∑NiUi = 3xN3+2xN2+1xN1 =3x0+2x2+1x3 = 7 Therefore, system A has greater energy 17. Consider the system and the two states from question 16. Which state has greater multiplicity? Answer: For State A: W = 5!/1!3!1! = 20 Fo...
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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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