Question

Tutored Practice Problem 10.6.2 COUNTS TOWARDS GRADE Calculate enthalpy change using standard heats of formation. Using the standard heats of formation that follow, calculate the standard enthalpy change for the following reaction. H2S(g) 2H20(I) »3H2(g) +SO2(g) AH rxn kJ Species AHf(kJ/mol H2S(g) -20.6 H2O(D -285.8 SO2(g) -296.8 Check & Submit Answer Show Approach

Answer 1

Given:
Hof(H2S(g)) = -20.6 KJ/mol
Hof(H2O(l)) = -285.8 KJ/mol
Hof(H2(g)) = 0.0 KJ/mol
Hof(SO2(g)) = -296.8 KJ/mol

Balanced chemical equation is:
H2S(g) + 2 H2O(l) ---> 3 H2(g) + SO2(g)

ΔHo rxn = 3*Hof(H2(g)) + 1*Hof(SO2(g)) - 1*Hof( H2S(g)) - 2*Hof(H2O(l))
ΔHo rxn = 3*(0.0) + 1*(-296.8) - 1*(-20.6) - 2*(-285.8)
ΔHo rxn = 295.4 KJ
Answer: 295.4 KJ