Determination of the Solubility Product Constant for Calcium Sulfate: the Effect of Ionic Strengths of Electrolyte Solutions

Topics: Electric charge, Gypsum, Solution Pages: 4 (698 words) Published: September 28, 2010
In this experiment, the Ksp for calcium sulfate dihydrate, CaSO4·2H2O, by titrating 4 times a calcium sulfate dihydrate solution with diprotic EDTA, H2(EDTA)2-. For each trial we found the Ksp by means of molarities and activities. The results for the Ksp using only molarities was very different than the Ksp using activities. The average Ksp using molarity only was 2.26 x 10-4 and the average Ksp using activity turned out to be 2.31 x 10-5. The actual Ksp however, is 3.14 x 10-5. A percent error of 26.6 % was calculated.


In this experiment, a saturated calcium sulfate was already made and ready to use. 25.00 mL of this solution was then mixed with 10 mL of an ammonia buffer and 1 drop of eriochrome black 1 indicator. We then filled our burette 0.0168 M EDTA solution and began to titrate with the calcium sulfate solution prepared. This procedure was done 4 times. Results and Discussion

| |Ksp | |Trial 1 |2.25 x 10-4 | |Trial 2 |2.28 x 10-4 | |Trial 3 |2.27 x 10-4 | |Trial 4 |2.26 x 10-4 |

By finding the moles of EDTA used, the concentrations of Ca2+ and SO42- can be calculated. By finding the molarities of the two, the Ksp can also be calculated and the result are shown on Table 1. below Table 1. Ksp Using Molarities

When comparing these values to the actual Ksp of 3.14 x 10-5 it is safe to say that they are not close at all. The problem here can be said to be that the...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Determination of the Solubility Product Constant of Calcium Hydroxide Essay
  • Essay about Determination of the Solubility Product Constant of Calcium Hydroxide
  • Determination of a Solubility Product Constant Essay
  • Solubility Product Determination Essay
  • The Effect of Ionic Strength on the Solubility of an Electrolyte Essay
  • Essay on Lesson Plan Solubility and Solubility Product Constant
  • Solubility Product Constant Handout Essay
  • Determination of the Solubility of Calcium Hydroxide Essay

Become a StudyMode Member

Sign Up - It's Free