Question

b) 2C2H2(g) + 5O2(g)⟶4CO2(g) + 2H2O(l) 6.54 Calculate the heats of combustion for the following reactions from the standard enthalpies of formation listed in Appendix 2: (a) C2H4(g) + 3O2(g) ⟶2CO2(g) + 2H2O(l) (b) 2H2S(g) + 3O2(g) ⟶2H2O(l) + 2SO2(g)

Answer 1

Answer:

a.  ΔH⁸ =  -1420 kJ/mol       b. ΔH⁸ =  -1144.84 kJ/mol

Explanation:

a.

                 C₂H₄ (g) + 3 O₂ (g) ------------------------  4 CO₂ (g) + 2 H₂O (l)  ΔH⁸ = ?

ΔH⁸f  kJmol  52.47       0                                      -399.5            -285.83

ΔH⁸ = 2(-399.5) + 2 (-285.83) - (52.47)

ΔH⁸ =  -1420 kJ/mol

b.

                       H₂S (g) + 3 O₂ (g) ---------------------- 2 H₂O (l)  + 2 SO₂ (g)

ΔH⁸f  kJmol     -20.50     0                                    -285.83      -296.84

ΔH⁸ =  2(-285.83) + 2 (-296.84) - (-20.50)

ΔH⁸ =  -1144.84 kJ/mol