enthalpy and entropy

Question

The combustion of acetylene gas produces carbon dioxide and water according to the following equation:

2C₂H₂(g) + 5O₂(g)→4CO₂(g) + 2H₂O(g)

Use the following data to answer questions about the reaction at standard conditions:

a. Determine the enthalpy change for the reaction. (5 points)

b. Determine the entropy change for the reaction. (5 points)

Answer 1

2C₂H₂(g) + 5O₂(g) → 4CO₂(g) + 2H₂O(g)

227..............0.................-393.5........-241.8..........∆H values

∆Hrxn = ∑products - ∑reactants

∆Hrxn = (4x-393.5) + (2x-241.8) - (2x227) = -1574 + (-483.6) - 454

∆Hrxn = -2512 kJ/mol-K

2C₂H₂(g) + 5O₂(g) → 4CO₂(g) + 2H₂O(g)

200.9........205............213.7........188.7..........S values

∆S = ∑products - ∑reactants

∆S = 4x213.7 + 2x188.7 - 2x200.9 + 5x205

∆S = 855 + 377 - 402 + 1025

∆S = 1232 - 1427

∆S = -195 J/mol-K