Question

PART A. Use standard enthalpies of formation to calculate ΔH∘rxn for the following reaction:

C2H5OH(l)+3O2(g)→2CO2(g)+3H2O(g)

Express your answer using four significant figures.

PART B.

Use standard enthalpies of formation to calculate ΔH∘rxn for the following reaction:

CH4(g)+2O2(g)→CO2(g)+2H2O(g)

Express your answer using three significant figures.

PART C.

Use standard enthalpies of formation to calculate ΔH∘rxn for the following reaction:

C(s)+O2(g)→CO2(g)

Express your answer using four significant figures.

PART D.

Use standard enthalpies of formation to calculate ΔH∘rxn for the following reaction:

N2O4(g)+4H2(g)→N2(g)+4H2O(g)

Express your answer using four significant figures.

Answer 1

part-A

C2H5OH(l)+3O2(g)→2CO2(g)+3H2O(g)

ΔH∘rxn     = ΔH∘f products - ΔH∘f reactants

               = 3*-241.818 + 2*-393.5 - (-277.69)

               = -1235KJ/mole

part-B

CH4(g)+2O2(g)→CO2(g)+2H2O(g)

ΔH∘rxn     = ΔH∘f products - ΔH∘f reactants

                 = 2*-241.818 -393.5-(-74.81+ 2*0)

                 = -802.3KJ/mole

part-C

C(s)+O2(g)→CO2(g)

ΔH∘rxn     = ΔH∘f products - ΔH∘f reactants

                 = -393.5-(0 + 0)   = -393.5KJ/mole

part-D

N2O4(g)+4H2(g)→N2(g)+4H2O(g)

ΔH∘rxn     = ΔH∘f products - ΔH∘f reactants

                 = 4*-241.818+0 - (9.16+ 4*0)

                 = -976.4KJ/mole