For the following problems involving thermodynamic data please consult the database of Robie et al. (1978), which I have uploaded to the course folder. The PDF is searchable, but not perfectly, presumably due to imperfect scanned-text recognition by the search algorithm. The easiest way to search the document is probably to go straight to the index at the end.
1. For the metamorphic reaction [grossular + quartz == anorthite + wollastonite, calculate the Gibbs free energy of reaction and the equilibrium constant at 298.15 K and at 1,000 K (1 bar total pressure). Does increasing temperature favor the formation of the assemblage grossular + quartz, or anorthite + wollastonite?
2. For the reaction converting perovskite and quartz to titanite, determine if the energetically-favored direction of the reaction at 500 K is forward (to titanite) or reverse, if the reaction is exothermic or endothermic, and what molar volume change (∂Vr) occurs during this reaction (at 500 K).
3. Calculate the de Broglie wavelength of an Ar atom moving at 500 m/s (roughly the velocity of air molecules at 25º C). How does this wavelength compare with the radius of an Ar atom?
4. For magnetite oxidation to hematite with O2, under standard conditions what partial pressure of oxygen gas in air would be buffered by this reaction, assuming no other sources of free molecular oxygen?
5. In a solution containing 0.02 mol/L Na+, 0.02 mol/L Cl-, 0.01 mol/L Ca2+, 0.02 mol/L Br-, and 0.005 mol/L Cu2+, determine the ionic strength of the solution and the activity (not concentration) of dissolved Cu2+.