1. Entropy/Enthalpy Practice

2. One reaction involved in the conversion of iron ore to the metal is: Entrance Question -11 kJ

3. Bond Enthalpy Problems 3CH 2 O + 3H 2 S → (CH 2 S) 3 + 3H 2 O 4NH 3 + 3O 2 → 2N 2 + 6H 2 O ΔH = KJ

4. Calculating ΔH f for a substance Calculate the heat of formation ΔH f for pyrite (FeS 2 ) in kJ / mol given the following information: ΔH f SO 2 = -296.1 KJ/mol and ΔH f Fe 2 O 3 = -822.2 KJ/mol 4FeS 2 + 11O 2 → 2Fe 2 O 3 + 8SO 2 ΔH rxn = -­3310 kJ

5. Heat Transfer/Phase Change Question You drop a 25 gram piece dry ice (frozen CO 2 ) with an initial temperature of -90°C into a 200 ml cup of water with an initial temperature of 25°C. Once the CO 2 gas bubbles out at its sublimation temperature of - 78.5°C, the water reaches a final temperature of 4°C. What is the heat of sublimation value for CO 2, if it has a specific heat of 1.24 J/g°C when still solid?

6. Calculate the ∆H for the following equation using both ∆H f and bond enthalpy C 2 H 4 (g) + H 2 O (g)  C 2 H 5 OH (l)

7. Draw an energy graph to show the activation energy and enthalpy change of this reaction. C 2 H 4 (g) + H 2 O (g)  C 2 H 5 OH (l) Label all axes and parts of the graph

8. Calculate the ∆S for the following equation using the entropy table C 2 H 4 (g) + H 2 O (g)  C 2 H 5 OH (l)

9. What is ∆G at 300C? C 2 H 4 (g) + H 2 O (g)  C 2 H 5 OH (l)

10. Under what circumstances would this reaction be spontaneous? C 2 H 4 (g) + H 2 O (g)  C 2 H 5 OH (l)

11. C 2 H 5 OH (l) + O 2 (g)  CO 2 (g) + H 2 O (g) Calculate the ∆H for the combustion of ethanol using the ∆H f table below and the bond enthalpy chart.

12. C 2 H 5 OH (l) + O 2 (g)  CO 2 (g) + H 2 O (g) If a 100 ml beaker of water at 15ᵒC were heated by 4 grams of burning ethanol, how much would the temperature of the water rise, assuming no heat is lost to the surroundings?

13. Use Hess’s Law to find the change in entropy for the following reaction: Solve for the entropy change of 8S 8 (s) + 12O 2 (g)  8SO 3 (g). Given: S 8 (s) + 8O 2 (g)  8SO 2 (g) ΔS = 89 J/K SO 2 (g) + ½ O 2 (g)  SO 3 (g) ΔS = -94 J/K ΔS = -663 J/K.

14. Use Hess’ Law to Solve for the Spontaneity of the Reaction 4CO (g) + 2NO 2 (g)  4CO 2 (g) + N 2 (g) ΔG = ??? Use the following reactions and given ΔG values 2NO (g) + O 2 (g)  2NO 2 (g) ΔG = -72.6 kJ CO (g) + ½O 2 (g)  CO 2 (g) ΔG = -257.2kJ ½O 2 (g) + ½N 2 (g)  NO (g) ΔG = 87.6 kJ ΔG = -1131.4 kJ