Chem 178 SIWednesday, Septemeber 5, 2007Entropy (Chapter 19)1. What are the units of ∆S?2. State the first law of thermodynamics. (review from 177)3. State the second law of thermodynamics.4. State the third law of thermodynamics.5. What is the sign of ∆H for an exothermic process? (review from 177)6. What is the sign of q for an endothermic process? (review from 177)7. Rank the following in order of increasing entropy: liquid, solid, gas.8. Predict the sign (+/-) of ∆S for the following reactions:a) 2NO2(g) → N2O4(g)b) C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g)c) 2SO2(g) + O2(g) → 2SO3(g)d) CO(g) + 2H2(g) → CH3OH(g)e) 2H2(g) + O2(g) → 2H2O(l)f) N2(g) + 3H2(g) → 2NH3(g)g) Ca(OH) 2(s) → Ca2+(aq) + 2OH-(aq)9. Predict the sign of the entropy change for:a) the condensation of steam to liquid waterb) the sublimation of a solidChem 178 SIWednesday, Septemeber 5, 200710. Will the entropy change for each of the following be positive or negative?a) Moisture condenses on the outside of a cold glass.b) Raindrops form in a cloud.c) Gasoline vaporizes in the carburetor of an automobile engine.d) Air is pumped into a tire.e) Frost forms on the windshield of your car.f) Sugar dissolves in coffee.11. Calculate ∆Sº for the following reactions in J/K from the data table in your book. On the basis of their values of ∆Sº, which of these reactions are favored to occur spontaneously?a) N2(g) + 3H2(g) → 2NH3(g)b) CO(g) + 2H2(g) → CH3OH(g)c) 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g)d) Ca(OH) 2(s) + H2SO4(l) → CaSO4(s) + 2H2O(l)e) S(s) + 2N2O(g) → SO2(g) + 2N2(g)12. Calculate ∆Sºf for the following compounds in J/molK a) C2H4(g) b) N2O(g)c) NaCl(s) d) CaSO4 2H2O(s)e)
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