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and be careful not to disturb the beaker. Record your observations. Allow the beaker to
sit undisturbed as you continue on with the rest of the experiment, periodically taking
Your professor may have a demonstration of a natural semi-permiable membrane
set up. If so, take observations on the demonstration.
Solubility of Gases:
1. Ammonia (CAUTION! CORROSIVE, TOXIC, LACRYMATOR) is highly
soluble in water. Your professor will demonstrate this for you with what is known as the
“Ammonia Fountain Demonstration.”
Solubility of Compounds in Polar and Non-Polar Solvents:
Water is a polar solvent, hexane is non-polar. In six test tubes, put 1 mL of water into
each. In six different test tubes, put 1 mL of hexane (CAUTION! Toxic, highly
flammable) into each. Pair the test tubes, one with water and one with hexane, into four
pairs. Add equal amounts of each of the following to each of the two test tubes within a
pair; Dakota State University page 169 of 232 Experiment 16: Colligative Properties General Chemistry I and II Lab Manual (1) sodium chloride (an ionic compound); the tip of a spatula full (about 0.1 g)
(2) calcium phosphate (CAUTION! Toxic) (an ionic compound); the tip of a
spatula full (about 0.1 g)
(3) table sugar (sucrose, a polar covalent compound); the tip of a spatula full
(about 0.1 g)
(4) Naphthalene (CAUTION! Toxic, flammable, toxic fumes) (typical
ingredient of urinal cakes; a non-polar covalent compound); the tip of a spatula full
(about 0.1 g)
(5) Ethylene glycol (CAUTION! Toxic) (typical ingredient in antifreeze; a polar
covalent liquid); about 3 drops (enough to see)
(6) Paraffin Oil (CAUTION! Toxic, flammable) (a non-polar covalent liquid);
about 3 drops (enough to see)
Agitate each solution by flicking the test tube. Describe what happens in each.
Effect of Temperature on Solubility:
Using a clean beaker, begin heating about 50 mL of distilled H2 O. Place each of
the following into three medium sized test tubes:
(1) 2 g potassium sulfate K2 SO4 (CAUTION! Toxic)
(2) 7 g sodium sulfate Na2 SO4 (CAUTION! Toxic)
(3) 5 g potassium chloride KCl (CAUTION! Toxic)
When the water reaches a temperature between 30 and 40o C, add 10 mL of warm water
to each of the test tubes. Agitate well, but not all of the solute will dissolve. Continue
heating the water.
Once you have taken your observations, place the test tubes in the heating water.
Continue heating the water, carefully agitating the solutions periodically, until the water
is about 100o C (about boiling). Record your observations.
We are going to make three solutions of more or less equal concentration. To do
so, make each of the following solutions in three different test tubes:
(1) Put 20.2 g of potassium nitrate (0.2 mol) and 20 mL of water, and agitate to
(2) Put 38.4 g of sugar (0.2 mol) and 20 mL of water, and agitate to dissolve.
(3) Put 11.14 mL of ethylene glycol (0.2 mL) and 20 mL of water, and agitate to
Heat each test tube carefully in turn until the liquid begins to boil, with the Pasco
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