chap-19-2011W-a

# Atm and so rxn aa bb cc dd c s o c d s o

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Unformatted text preview: at STP (4) 1 mole of H2 (g) at STP or 1mole of NO2 (g) at STP Entropy Entropy Changes in the System (∆Ssys) The standard entropy of reaction ( ∆So ) is the entropy rxn change for a reaction carried out at 1 atm and 250C. atm and ∆So rxn aA + bB cC + dD → = [c ⋅ S o (C ) + d ⋅ S o ( D)] − [a ⋅ S o ( A) + b ⋅ S o ( B )] ∆So = ∑ nS o (products) − ∑ mS o (reactants) rxn What is the standard entropy change for the following reaction the at 250C? 2CO(g)+O 2 (g) 2CO 2 (g) S0(CO)=197.9 J/K•mol S0(CO2) = 213.6 J/K•mol S0(O2) = 205.0 J/K•mol ∆S0 = 2 × S0(CO2) – [2 × S0(CO) + S0 (O2)] rxn ∆S0 = 427.2 – [395.8 + 205.0] = -173.6 J/K•mol rxn Entropy Entropy Changes in the System (∆Ssys) When gases are produced (or consumed) gases • If a reaction produces more gas molecules than it consumes, ∆n = n ∆Srxn > 0 −n >0 ga...
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## This document was uploaded on 02/26/2014.

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