2. refers to the maximum quantity
of solute that can dissolve in a
given quantity of solvent at a
given temperature. The variation
of solubility for compounds is
dependent on several factors.
3. Objective: To investigate the
effect of temperature on the
solubility of sugar in water.
Materials: 100 ml of distilled
water, sugar, hot plate or Bunsen
burner, spatula and thermometer.
› 1. Measure 100 ml of distilled water at room
temperature and record its temperature.
› 2. By using a spatula, add sugar in a small amount
at a time to the water while stirring the solution
after each addition of sugar, until the sugar no
› 3. Heat the solution to 50*C. Record your
observation. Add more sugar to the solution until
the sugar no longer dissolves. Stir after each
› 4. Repeat step 3 at 60*C and 70*C . Record your
6. Solids don’t dissolve very well in cold water
as much as hot water does.
The hotter the water, the faster solids will
dissolve in water
Solids increase solubility as temperature
increases.(most of liquids expect for
Na2SO4 and Ce2(SO4)3
7. Objective: To determine the effect of
temperature on the solubility of gases.
Materials: Dark colored soda, three 1 mL test
tubes with stoppers, beakers, graduated
cylinder, water at room temperature, ice-cold
water, and hot water
› 1. Fill at least half of three test tubes with the same
amount of soda. Put a stopper in the test tube.
› 2. Prepare three water baths: cold, room
temperature, and hot (not higher than approximately
› 3. Invert a cork-screwed test tube in each water
bath. Observe the rate of bubble formation in each
beaker. Note also the amount of gas at the top of
each test tube.
9. In which test tube is
the rate of bubble
formation the fastest?
10. The solubility of Gas in water decreases as
the temperature increases.
The solubility of Gas in water increases as
the temperature decreases
11. Objective: To investigate the
effect of pressure on the
solubility of gases.
Material: An unopened plastic
bottle of carbonated drink.
› 1. Take the bottle of carbonated drink and try to
squeeze it. Observe how the bottle feels. Observe
also the rate of bubble formation. Record your
› 2. Carefully open the bottle and let the gas escape.
Reseal the cap and try to squeeze the bottle again.
Now, observe the rate of bubble formation. Record
13. When carbonated drinks are bottled, they are
pressurized; that is why they are hard to
squeeze. Pressurizing the bottles prevent the
carbon dioxide from escaping the solution. The
solubility of a gas in a liquid is proportional to
the pressure of the gas over the solution. This
relationship between gas solubility and pressure
is known as Henry’s Law, which was formulated
by an English Chemist named William Henry in
1803. The mathematical statement is given by:
14. c is the molar concentration (mol/L) of the
P is the pressure (in atm) of the gas over the
And k is the constant for the given gas-
where k depends mainly on the temperature,
and has the units mol/L.atm
15. Sample Problem:
› Calculate the molar concentration of nitrogen in
water at 25*C for a partial pressure of 0.78 atm. The
Henry’s Law constant for nitrogen at this
temperature is 6.8X10^-4 mol/L. atm.
› Using the equation: