Untitled - Kelly Walsh High School

176 CHEMISTRY FOR THE UTTERLY CONFUSED
Quick Tip
The sum of all the mole fractions of the components of a solution should equal 1.00.
Dilution
Another way to prepare a solution is by diluting a more concentrated solution
to a more dilute one by adding solvent. You can use the following equation:
(C before dilution) (V before dilution) (C after dilution) (V after dilution)
In this equation, C represents any concentration unit and V is any volume unit,
as long as the same concentration and volume unit are used on both sides.
Determine the final concentration when 800.0 mL of water is added to 300.0 mL
of a 0.1000 M solution of HCl. Assume the volumes are additive.
Mbefore 0.1000 M Mafter ?
Vbefore 300.0 mL Vafter (300.0 800.0) mL
Mafter (Mbefore)(Vbefore)/(Vafter) (0.1000 M)(300.0 mL)/(1100.0 mL)
0.02727 M
12-2 Temperature and Pressure Effects
on Solubility
The solubility of most solids increases with increasing temperature. However,
the solubility of gases in liquids decreases with increasing temperature. For
example, if you open a cold bottle of soda and a warm bottle of soda, more gas
is released by the warm soda. This is the basis of thermal pollution, in which the
solubility of oxygen in stream or lake water is decreased if the water is polluted
by heat.
The solubility of liquids and solids are, in general, not affected by changes in
pressure. However, the solubility of gases is affected. The greater the pressure
is, the greater the solubility of the gas in a liquid.