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Exam II Thursday, November 1, 7:00-9:00 pm; rooms are on the website. Conflict: (11/1) 4:30-6:30pm in 219 Greg; sign up in 1026 CA starting Friday Conflict with conflict? Email me right away. Review sessions: Monday (10/29): 217 Noyes Lab (6-8 pm) Tuesday (10/30): 163 Noyes Lab (6-8:30 pm)

Exam II Practice exam will be posted sometime Friday. Take when you feel ready for the exam. Take as an actual exam (not just more practice problems). See the front of the exam for information that you are given and the number of problems.

Clicker Question Determine the signs of ΔH, ΔS, and ΔG for the freezing of liquid water at 2°C and 1 atm. ΔH ΔS ΔG a) – – – b) – – + c) + + + d) + – 0 e) – + 0  

Clicker Question For the melting of ice at 10°C and 1 atm what are the signs for ∆H, ∆S, and ∆G? ΔH ΔS ΔG a) + – 0 b) – + 0 c) + + + d) + + – e) – + –  

Determining Grxn Consider the following reaction at constant temperature and pressure: 2CO(g) + O2(g)  2CO2(g) Consider: 1. Predict if S° is positive or negative (we will determine it next). 2. Predict if the reaction is exothermic or endothermic (we will determine it next). 3. Can we predict the sign of G°? 4. At what temperatures is this reaction spontaneous?

Determining Grxn 2CO(g) + O2(g)  2CO2(g) G (kJ/mol) -137 0 -394 H (kJ/mol) -110.5 0 -393.5 S (J/Kmol) 198 205 214 Consider: 1. Determine S° (check prediction). 2. Determine H° (check prediction). 3. Determine G° two ways. 4. At what temperatures is this reaction spontaneous?

Clicker Question For the reaction 2HF(g) H2(g) + F2(g), G° = 38.3 kJ, at 1000 K. If, at this temperature, 5.00 mol of HF(g), 0.500 mol of H2(g), and 0.75 mol of F2(g) are mixed in a 1.00-L container: a) Some HF will decompose (to yield H2 and F2). b) Some HF will be formed (from H2 and F2). c) The system is at equilibrium. d) Not enough data are given to answer this question. e) I do not know.