1. (a) 0.504 g of H2 reacts with O2 at constant pressure evolving 17.0

1.	1. (a) 0.504 g of H2 reacts with O2 at constant pressure evolving 17.08 kcal. Calculateenthalpy change for the reactionH2(g) +1/2O2 (g) > H20 (l)
Answer» We know that, ΔCp = ΣnCp PRODUCTS - ΣnCp REACTANTS = [(1x 75.312) - ( 1x 38.83 - 1/2 x 29.16 )] = 51.06 J/K/mol = 0.051 kJ/K Further , we know from Kirchoff's law, ΔH(at FINAL temperature) –ΔH(at INITIAL temperature) =[ (Cp(final) -Cp (initial) (T(final ) -T( initial)] = ΔCp (Tf -Ti ) Or, ΔH ( 373K) - ΔH (298K) = ΔCp (Tf -Ti ) Or, ΔH ( 373K)- (-285.76 kJ/K) = 0.051kJ/K x ( 373K-298K) = 3.825 kJ or, ΔH ( 373K) = 3.825 - 285.76 = -281.93 kJ Hence, ΔH ( at 373K) = -281.93 kJ

1. (a) 0.504 g of H2 reacts with O2 at constant pressure evolving 17.08 kcal. Calculateenthalpy change for the reactionH2(g) +1/2O2 (g) > H20 (l)

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