The Periodic Law states that properties of the elements vary in predictable, repeatable ways.  These properties include what kinds of compounds an element will form, and the properties of those compounds.  This allows chemists to predict the properties of undiscovered compounds or elements.  In this lab, we will determine the solubility of three alkali metal chlorides, and use these solubilities to predict those of two others.  Click here to see the score sheet for this lab.

Objectives

• Determine the solubility of two of the following:  LiCl, NaCl, and KCl, in grams/100g of water.
• Determine the class average solubilities for all three of the chemicals listed above, in grams/100g of water.
• Predict the solubility of HCl and RbCl, in grams/100g of water, based on the class average results.

1. Make a saturated solution of one of the chlorides by adding a small scoop to a small test tube with distilled water, covering, and shaking.  Repeat until some solid remains un-dissolved.
2. Clean an evaporating dish and watch glass, and dry them by heating over a Bunsen burner.  When they have cooled, determine their mass.
3. Decant a small part of your saturated solution (about the size of a quarter or half-dollar) into the evaporating dish.  Determine the mass of the dish, watch glass, and solution.
4. Use a hot plate or bunsen burner to heat the solution to dryness.  The watch glass will prevent splattering.  When the solution is completely dry, allow it to cool and determine the mass of the dish, watch glass, and solid residue.  Repeat this step until the mass does not change more than 0.01 g.  Record the final combined mass of the dish, glass, and salt.
5. Repeat for another chloride.
6. Obtain data from the class to determine the average solubilty for each salt.
7. Use the class's average results to predict the solubility of HCl and RbCl.  Explain your reasoning very clearly.

1. Define Solute.
2. Define Solvent.
3. How can you tell if a solution is saturated?
4. [Write out the electron configuration for Lithium, Sodium, and Potassium.]

Data/Results
 

                     Predicted solubilty for HCl: __________                                 Predicted solubility for RbCl: __________
 
 

[Solubility Trends score sheet][MHS Chem page]