Question

a) Calculate the enthalpy of the reaction 2NO(g)+O2(g)→2NO2(g) given the following reactions and enthalpies of formation:

12N2(g)+O2(g)→NO2(g), ΔfH∘A=33.2 kJ mol−1

12N2(g)+12O2(g)→NO(g), ΔfH∘B=90.2 kJ mol−1

Express your answer with the appropriate units.

b) Calculate the enthalpy of the reaction 4B(s)+3O2(g)→2B2O3(s) given the following pertinent information:

B2O3(s)+3H2O(g)→3O2(g)+B2H6(g), ΔrH∘A=+2035 kJ mol−1

2B(s)+3H2(g)→B2H6(g), ΔrH∘B=+36 kJ mol−1

H2(g)+12O2(g)→H2O(l), ΔrH∘C=−285 kJ mol−1

H2O(l)→H2O(g), ΔrH∘D=+44 kJ mol−1

Answer 1