Use data from Appendix IIB to calculate ?S?rxn in J/K for each of the reactions given below.
A. 3NO2(g)+H2O(l)?2HNO3(aq)+NO(g)
B. Cr2O3(s)+3CO(g)?2Cr(s)+3CO2(g)
C. SO2(g)+12O2(g)?SO3(g)
D .N2O4(g)+4H2(g)?N2(g)+4H2O(g)
A. 3NO2(g) + H2O(l) --------------------> 2HNO3(aq) + NO(g)
S0reaction = S0products - S0reactants
= (2 x S0HNO3 + S0NO) - (3 x S0NO2 + S0H2O)
= (2 x 146 + 210 ) - (3 x240.1 + 69.9)
= -287.4 J/K
B. Cr2O3(s)+3CO(g)----------------->2Cr(s)+3CO2(g)
S0reaction = S0products - S0reactants
= (2 x S0Cr+ 3 x S0CO2) - ( S0Cr2O3 + 3x S0CO)
= (2 x 23.62 + 3 x 213.6) - (81.17 + 3 x 197.9)
= 7.17 J/K
C. SO2(g)+1/2O2(g) -----------------> SO3(g)
S0reaction = S0products - S0reactants
= S0SO3- ( S0SO2 + 1/2x S0O2)
= 256.65 - (248..11 + 1/2 x 205.0)
= -93.96 J/K
D .N2O4(g)+4H2(g) ------------------> N2(g)+4H2O(g)
S0reaction = S0products - S0reactants
= ( S0N2+ 4 x S0H2O) - ( S0N2O4 + 4x S0H2)
= (191.5 + 4 x188.8 ) -(304.18 + 4 x 130.7)
=119.72 J/K
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