Calculate H for the reaction of sulfur dioxide with oxygen.

Question

2SO (g) + O (g)   2SO (g)

( H SO (g) = –296.8 kJ/mol;  H SO (g) = –395.7 kJ/mol)

Answer 1

2SO2(g) + O2(g) ==> 2SO3(g)

∆Hrxn = ∑∆H_products - ∑∆H_reactants

∑∆H_products = -395.7 kJ/mol x 2 mols = -791.4 kJ

∑∆H_reactants = -296.8 kJ/mol x 2 mols + 0 for O₂ = -593.6 kJ

∆Hrxn = -791.4 kJ - (-593.6 kJ)

∆Hrxn = -197.8 kJ