CHM 2046C Module 13 Sample Name: __ Answer _____

Part E: Reaction Spontaneity Calculation: 10 points

The quantity called the Gibbs free-energy change (∆G),

∆G = ∆H - T∆S, determines whether a chemical or physical process will occur spontaneously. Iron metal can be produced by reducing Iron III oxide (rust) with Hydrogen:

Fe₂O₃ (s) + 3 H₂ ---> 2 Fe (s) + 3 H₂O (g) ∆H^o = +98.8 kJ; ∆S^o = +341.5 kJ/K

(a) Is this reaction spontaneous under standard state conditions at 25^oC?

(b) At what temperature will the reaction be become spontaneous?

Worked Example 16.5 Page 663