SciHawks

AP Chem - Unit exam on acid/base/buffer equilibria tomorrow; this is our THIRD test in a row on equilibrium.
Review all notes; re-write all examples until you understand the logic of the problem-solving process!
Do as many practice problems as is necessary to be confident in doing any problem type!
Questions types covered:

• how to make a buffer including choosing the correct quantities of appropriate salts, acids, and bases to produced a solution of a desired pH.
• quantitatively determining the effect of adding a given quantity of strong acid or base to either a buffer, or to a weak base or weak acid, respectively
• the above requires knowledge of when and when not to use the H-H equation, and the assumption built into any practical use of that equation i.e. initial = equilibrium concentrations.
• qualitatively and quantitatively assess each of the four types of titration curves, knowing the relative concentrations of conjugates at each point, determining pKa's , pKb's from the graph.
• quantititatively determining the concentration of any species in solution at any point in any titration of a weak acid or base, and sketching the accompanying curve; also determining Ka, Kb, pKa, pKb from titration curve data or pH measurements at particular points of the titration.
• choosing an appropriate acid-base indicator that will change color at/near the equivalence point of a given titration, and explaining quantitatively and qualitatively how that is the appropriate choice
• drawing and analyzing the titration curve of a polyprotic acid titrated by a strong base
• I will separately test Lewis acids/bases on a future descriptive chem quiz.

 we determined the magnitude of the solubility "suppression" of a given salt in a solution containing a common ion of that given salt.
We then determined "will a precipitate form?" by determining and comparing the value of Qsp to Ksp.
If precipitation occurs after mixing of two aqueous solutions, we then use SRFC and ICE organizers to determine the percent precipitation of a given ion, and the number of grams of precipitate formed at equilibrium.
This is not easy; there are many pitfalls in these problems, as you experienced today! Repeated practice and daily review are required.

Bio - we began our new unit on Modern Genetics by discussing the experiments of Mendel, how they were fair, logical i.e. scientific, and led to a discovery of the patterns of inheritance i.e. the Laws of Inhertance.