Essay on So Mexicans are Taking Jobs from Americans Notes

867 WordsNov 8, 20144 Pages
AP Chemistry Background The solubility product constant, Ksp, is a particular type of equilibrium constant. The equilibrium is formed when an ionic solid dissolves in water to form a saturated solution. The equilibrium exists between the aqueous ions and the undissolved solid. A saturated solution contains the maximum concentration of ions of the substance that can dissolve at the solutions temperature. A knowledge of the Ksp of a salt is useful, since it allows us to determine the concentration of ions of the compound in a saturated solution. This allows us to control a solution so that precipitation of a compound will not occur, or to find the concentration needed to cause a precipitate to form. The solubility product which will be…show more content…
(Hint the concentration of calcium ions in well 12 is 4.9 x 10-5 M.) Place 5 drops of 0.10 M NaOH in each of the wells 1 through 12. When the NaOH is added to each well, the initial concentrations of the reactants are halved, as each solution dilutes the other. Use an empty pipet to mix each of these combined solutions by drawing each solution up into the pipet and squirting it back into the well. (Hint the concentration of Ca2 ions in well 12 is 2.4 x 10-5 M.) Allow three or four minutes for the precipitates to form, then observe the pattern of precipitation. At one point the concentration of both ions becomes too low to have any precipitate form. We will assume that the first well with no precipitate represents a saturated solution. Part B NaOH varies, Ca(NO3)2 held constant To check your results, repeat the procedure but use a serial dilution of the NaOH. In a different row, put 5 drops of 0.10-M NaOH in well 1. Put 5 drops of distilled water in wells 2 through 12. Add 5 drops of the 0.10-M NaOH solution to well 2. Use an empty pipet to mix the solution by pulling the solution into the pipet and then squirting it back several times. The solution in this well, 2, is now 0.050 M in OH- ion. Continue this serial dilution to well 12, and then remove 5 drops from well 12. Add 5 drops of 0.10 M Ca(NO3)2 to each of the wells, and mix each with an empty pipet or stirrer. Again, determine the well where no more precipitate appears. Cleanup
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