Question

THIS IS A FOUR PART QUESTION. HELP NEEDED. THANK YOU VERY MUCH.

a) Using the solubility of Ca(IO3) 2 that you determined in pure water, calculate the value of K sp using only concentrations, that is assuming that all activity coefficients are 1.0. Use 3 sig figs. Solubility of Ca(IO3)2 in Water: 0.00828 mols/L

b) Using the solubility of Ca(IO3)2 that you determined in 0.01M KIO3 as a solvent (the answer from part a), calculate the value of Ksp using only concentrations, that is assuming that all activity coefficients are 1.0. Solubility of Ca(IO3)2 = 0.00327

c) The next few questions will incorporate activity effects into the calculation of Ksp for Ca(IO3)2 using your data from the saturated solution of Ca(IO3)2 in pure water.To do so, we must first know the ionic strength of the solutions. Use your value of the solubility of Ca(IO3)2 in pure water to calculate the ionic strength of that solution.

d) Using the value of the ionic strength of a saturated solution of Ca(IO3)2 in pure water, use TABLE I under the solubility product experiment from the laboratory manual, and enter the activity coefficient for Ca2+ ions listed there at the ionic strength closest to that of the saturated solution of Ca(IO3)2 in pure water. If your ionic strength happens to lie exactly between two values in TABLE I, then use the activity coefficient for the higher ionic strength.

If you need any other information, please let me know.

Table 1. Activity Coefficients for Aqueous Solution at 25 C onic Strength (H M) 0.001 0.005 0.01 0.05 0.1 0.15 On 0.967 0.933 0.914. 0.86 0.83 0.81 0.965 0.929 0.907 0.835 0.80 0.77 Na IO3-, HCO3-, H2PO4 0.775 0.964 0.928 0.902 0.82 0.76 OHT, FT, SCNT, Mno4 CIO4 0.964. 0.926 0.900 0.81 0.76 0.73 0.964 0.925 0.899 0.805 0.755 0.72 K+, CI-, B IT, CNT, NO3 0.898 0.80 0.75 0.71 Rb+, Cs+, NH4+, Ag 0.964 0.924 0.69 0.52 045 041 2+ Be Mg 0.872 0.755 2+ 2+ 2+ 2+ 0.870 0.485 0.405 Ca Cu Zn Mn Sr Ba cd2+, Hg S2 0.465 .744 0.67 2+ CO3 SO3 Pb 0.867 0.665 0.742 0.455 Hg22+, so42-, cro42 HPO42- 0.660 0.445 0.867 0.355 0.740 3+ 3+ 3+ Fee Cr 0.738 0.54 0.445 0.245 0.18 0.15 0.16 0.505 0.095 0.066 PO4 0.725 0.395 0.35 0.255 0.10 0.065 0048 4+ Sn 0.588 Source: Data from J. Kielland, Amer. Chem. Soc.,59, 1675 (1937) As an example of how to use activities, hereis a calculation ofthe concentration of calcium ion in a 0.0125 M solution of magnesium sulfate MgSO4 saturated with calcium fluoride CaF2. The concentration of calcium is going to depend on how much calcium fluoride dissolves, so the chemical equilibrium and initial set-up of interest is Ca2+ (aq) 3.9 x 10-11 CaF2 (s) 2F (aq) Initial: solid Final solid 2x