Transcript Solutions & Solubility “Henry`s Law”

Mr. Gibson Room 213
Solubility of Gases in Solution
As a function of temperature & Pressure
Solubility - Gases
 There are three things
that affect the solubility
(the ability to dissolve)
of a solute into a solvent.
1.
Surface area of the
solute.
You can crush a
crystalline solid (thus
make smaller crystals).
By doing this… you’ve
increased the surface
area which allows more
efficient flow of solvent
Solubility - Gases
 There are three things
that affect the solubility
(the ability to dissolve)
of a solute into a solvent.
1.
Surface area of the
solute.
You can crush a
crystalline solid (thus
make smaller crystals).
By doing this… you’ve
increased the surface
area which allows more
efficient flow of solvent
Solubility - Gases
 There are three things
that affect the solubility
(the ability to dissolve)
of a solute into a solvent.
2. Temperature of the
solvent.
Solubility - Gases
 There are three things
that affect the solubility
(the ability to dissolve)
of a solute into a solvent.
3. Increasing the pressure
above the solution.
Solubility of Gases
 As a side-bar…
 What is the “equivalent
fraction” in the problem
to the right?
1= X
2 4
Solubility of Gases
 When you converted the
one-half to two-fourths
what exactly did you do
to the “2” to get it to be a
“4”?
1= X
2 4
Solubility of Gases
 Exactly! You doubled it.
 And as the “2” “went up”
to be a “4”….
 The “1” also had to “go
up” to become a “2” (you
doubled it too).
1= X
2 4
Solubility - Gases
 When we have dissolved
a GAS into a liquid
solvent…
 Henry’s Law applies
when calculating all
sorts of things.
 Henry’s Law states:
 At a given temperature…
 The solubility (S) of a gas
in a liquid is directly
proportional to the
pressure (P) of the gas
ABOVE the liquid.
Solubility - Gases
 Henry’s Law
 At a given temperature…
 The solubility (S) of a gas
in a liquid is directly
proportional to the
pressure (P) of the gas
ABOVE the liquid.
S1 = S2
P1 P2
Where P or pressure is
stated in the unit
“atmospheres” (atm);
Solubility is stated as g/L
Solubility of Gases
 So… just like our
equivalent fraction
exercise earlier…
 You are usually given
three of the four
numbers in Henry’s law
and you simply have to
isolate the unknown “4th”
number and solve.
1= X
2 4
Solubility - Gases
 Henry’s Law
 As practice… do
problems 1 & 2 on page
461 in your texts using
the schoolrack uplink to
submit your work.
S1 = S2
P1 P2
Where P or pressure is
stated in the unit
“atmospheres” (atm);
Solubility is stated as g/L