1. Chapter 16 pp Spontaneity, entropy and free energy Note: For online HW, you might need to use the thermodynamic data sheet posted on my downloads website in the “helps” section if the values are not already in the problem. You need to use ∆G values that have at least one decimal place and your textbook only goes to the “one’s” place.

2. Z5e 791 16.1 Methane and Oxygen React The products have lower potential energy than the reactants, resulting in energy flow (heat) to the surroundings.

4. Z5e 792 Figure 16.2 Rate of Reaction Rate is a function of the pathway (kinetics) Spontaneity is a function of the potential energies (thermodynamics)

9. Figure 16.4 Three Possible Arrangements (states) of Four Molecules in a Two-Bulbed Flask (Each arrangement has several microstates as seen in next slide)

17.  S sys  S surr  S univ Spontaneous? - - - + + + + - ? Yes No, Reverse At low temp (  s surr magnitude >  S sys At high temp (  s sys magnitude >  S surr Z5e 803 Table 16.3 pp + - ?

22.  G =  H - T  S pp + - At all Temp & exotherm + + At high temp & endoth., “ entropy driven” - - At low temperatures, “ enthalpy driven” + - Not at any temperature, Reverse is spontaneous  H  S Spontaneous?

27. Calculations Involving Energy If 2 mol reactants  4 mol product + 500 kJ, is the rxn likely spontaneous? Yes What is the sign of ∆S rxn when molten wax hardens? (-) How would your calculations change if the coefficients were not 1? ∆ H f and S values in  Gº =  Hº - T  Sº multiplied by the coefficients.

43. Figure 16.9 Free Energy and Equilibrium a.  Gº to reach =m, beginning with 1.0 mol A (g ) & P A = 2.0 atm b.  Gº to reach =m, beginning with 1.0 mol B (g) & P B = 2.0 atm c. G profile for A (g) B (g) with 1.0 mole of each at P total = 2.0 atm. Each point on the curve corresponds to the total free energy of the system for a given combination of A and B.

53. Figure 16.10 A Battery A battery can do work by sending current to a starter motor. It can be recharged by forcing current through it in the opposite direction.

54. Figure 16.10 A Battery If the current flow in both processes is infinitesimally small, w1 = w2 and the process is reversible

55. Figure 16.10 A Battery But, in real world, current flow is finite , so w2 > w1 and process is irreversible ; that is, the universe is different after the process occurs.

56. Figure 16.10 A Battery All real processes are irreversible.