Solvent Properties of Water
Purpose:
To test the solubility in water of a variety of compounds, having different degrees of polarity.
Background:
The polar nature of the water molecule is largely responsible for the remarkable solvent action of this
compound. Because of its polarity, water is able to dissolve both ionic compounds, such as sodium
chloride and copper sulfate, and polar covalent compounds, such as sugar and ammonia. In general,
only nonpolar molecules, such as gasoline and kerosene, do not dissolve in water. Many chemical
reactions and most biochemical reactions take place in water.
In this experiment, you will examine the relationship between a compound’s degree of polarity and its
solubility in water.
Equipment:
1 scoopula
1 test tube rack
safety goggles
test tubes
1 wash bottle
Chemicals:
Sodium chloride, NaCl
Sucrose, C12H22O11
Sodium thiosulfate, Na2S2O3
Calcium carbonate, CaCO3
Potassium sulfate, K2SO4
Ethanol, C2H5OH
Sodium acetate, NaC2H3O2
Ethyl acetate, C4H8O2
Hexane, C6H14
Xylene, C6H4(CH3)2
Cyclohexane, C6H12
Calcium hydroxide, Ca(OH)2
Glycerin, C3H8O3
Potassium chloride, KCl
Calcium sulfate, CaSO4
Distilled water
Procedure:
Wear your safety glasses throughout the experiment!
1. Examine the substances in the Chemicals section. Record the chemical formula and physical state
of each in the data table.
2. Test each of the substances for water solubility. Add 3 to 4 mL of distilled water to a test tube.
Add a very small quantity of the substance to be tested to the water. For solids, use a sample less than
the size of a match head. For liquids, use one drop. Be careful not to contaminate the chemicals with
each other.
3. Flick the test tube gently with the fleshy part of your finger and note what happens. If all of the
substance dissolves, add another small quantity and flick gently. Repeat the process several more
times if the material continues to dissolve. Describe each substance as insoluble (I) if none of the
substance appears to dissolve, slightly soluble (SS) if one or two samples dissolve, or very soluble
(VS) if more than two samples dissolve.
4. Dispose of the organic liquids (xylene, cyclohexane, ethyl acetate, hexane, and glycerol in the
waste beaker in the fume hood.