er, Solubility Product Constant of Sodium Chloride Introduction For slightly soluble salts, we have the equilibrium of a solid salt with its ions in solution. Since the concentration of a pure substance in the solid (or liquid) phase remains constant, the equilibrium constant expression may be simplified to a form called the solubility product law. The solubility product law states that in a saturated solution of a slightly soluble salt, the product of molar concentrations of its ions in its saturated solution is a constant, the solubility product constant or Ksp. For a salt composed of an ion with a positive charge and an ion with a negative charge: bem adi AB(s) → A*(aq) + B (aq) pilpnd abeb dn Ksp = [A*][B¯] %3D The solubility of NaCl is such that a Ksp for it may be experimentally determined by fairly simple procedures. You will also investigate how the addition of either of its ions to its saturated solution may, or may not result in the formation of a precipitate. Objectives In this experiment you will: Determine the solubility product constant of a solute Demonstrate precipitation of a common ion to a saturated solution. -noner02adinoasb ampon dslp 2aismng Equipment 2 beakers, 150 mL ot alangle eov ri e tongs antolp evaporating dish stirring rod graduated cylinder 2 test tubes 25 X 100 mLumsg1o nok u bioAgee ue esu20LA xel Procedure 1. Prepare a saturated solution of sodium chloride by adding 10 g of the salt to 25 mL of water in a beaker. Stir constantly until there is an excess of the solid in the bottom of the beaker. Decant thei saturated solution. 1s Record the mass of the evaporating dish. Measure approximately 10 mL of the salt solution into a graduated cylinder. Record the volume to the nearest 0.1 mL. Pour this sample of the saturated solution into the evaporating dish. Place the evaporating dish on a hot plate and evaporate the solution the dryness. Remove the hot evaporating dish with tongs and permit it to cool. When it is cool, record the mass of the evaporating dish and solid residue. Subtract the mass of the empty evaporating dish to find the mass of the NaCl. 2. SUA 26coud 3. Addition of common ions to a saturated solution of salt. a. To 5 mL of the saturated sodium chloride solution in a test tube, add two pellets of solid sodium hydroxide. Caution (Sodium Hydroxide is caustic and corrosive. Don't allow the pellets or solution to come in contact with your eyes or skin. If any base spílls on you, flush the area with water, and then tell your teacher.) Stir carefully to dissolve as much of the sodium hydroxide as possible. Record your observations. b. To 5 mL of the saturated sodium chloride solution in a test tube, add 5 mL of 2 M NaOH solution. Stir carefully. Record your observations. ons nouor 4. At the end of the experiment, follow the directions of your instructor for proper disposal of all waste materials. Clean all apparatus and wash your hands before leaving. enteteve Ksp of Sodium Chloride oyone elens Name: Data and Analysis Complete the data table below. Sigeum Mass of empty evaporating dish Volume of saturated NaCl solution whobia o 10,00 31.20 mL Mass of evaporating dish and NaCl uen noitgeoloon Mass of NaCI oelom emo0s Insobo noitotto moles of NaCl lengle as mol dlud vosilo Molarity of NaCI solution obstlu stlo Concentration of [Na*] stio Concentration of [CI] egnenou or 200ug erpia Ksp for NaCl sbieao omvibnsens er Conclusions 1. Calculate the molarity of your saturated NaCl solution. Show your work, including units. Record rOy your results above. 15 invo noitsidiv bos Suaesng 1oam bellu neinian -gmud isme er lo sro siliang ami isubivibnnodgosq to 2. Calculate the Ksp for sodium chloride and record your result above. 1ostab louziv siqovdesg oud sela 9o0saib eapein m to senae noitqsoohqoiq 3. Explain your observations for 3a. evedns bnb aus obeud nuondu pst noltgaaeY (bouoa eoebrol mam labnatog otgso 9otong lo 1evel anisy 4. Explain any differences in observations between 3a. and 3b. nemplgoteriq sm nienoborh aveneaotordg vorove boy eini vorgesonsrioergsbe vcie ebeumeo auodlud oela) pnibne initust