1. Solubility, Density, and Melting Point of Solids
Experiment 2
Solubility, Density, and Melting Point of Solids
Parts A, B, C, Unknown
CHE116

2. Purpose of This Experiment
Determine the solubility of a solid sample
Calculate the density of a solid sample
Determine the melting point (m.p.) of a solid with the melting point apparatus
Determine the identity of an unknown by its physical properties (solubility, density, m.p.)
Work in groups of 2 for the known solid
Work individually for the unknown solid
(lab partners must use different unknowns)
CHE116

3. Determination of Solubility
Use only a few crystals of solid
Place the solid in the bottom of a small test tube, add the appropriate liquid, and shake back-and-forth gently
If the solid dissolves, it is soluble (s) in the liquid. If the solid does not dissolve, it is insoluble (i) in the liquid. If the solid dissolves a little, but not completely, it is sparingly soluble (sp) in the liquid.
CHE116

4. Density Calculation
Density = mass / volume Mass is found with the lab balance (find mass, then find volume of that mass) Volume by difference
CHE116

5. Volume by Difference
Technique used to find the volume of irregularly shaped solids
Put enough liquid into a graduated cylinder, record volume (SF and units)
Add solid sample (of known mass) to this graduated cylinder, record volume (SF and units)
Calculate the volume of the solid
(volume liquid and solid – volume of liquid = volume of solid)
CHE116

6. Melting Point Determination
Use the melting point apparatus. Ask for help using the m.p. apparatus.
Crush a few crystals of your sample on weighing paper with the bottom of a test tube. (Press firmly to crush.)
Put crystals in a capillary tube, then you are ready to use the m.p. apparatus
CHE116

7. Identify Unknown Determine the density of the unknown solid.
Determine the solubility of the unknown solid.
Determine the m.p. of the unknown solid.
(as time permits, choose at least 2 from above)
Identify the unknown solid from list using your determined physical properties.
CHE116