Mr. Gibson Room 213Solubility of Gases in Solution

As a function of temperature & Pressure

Solubility - GasesThere 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 - GasesThere 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 - GasesThere are three

things that affect the solubility (the ability to dissolve) of a solute into a solvent.

2. Temperature of the solvent.

Solubility - GasesThere 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 GasesAs a side-bar…

What is the “equivalent fraction” in the problem to the right?

1 = X2 4

Solubility of GasesWhen you converted

the one-half to two-fourths what exactly did you do to the “2” to get it to be a “4”?

1 = X2 4

Solubility of GasesExactly! 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 = X2 4

Solubility - GasesWhen 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 - GasesHenry’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 GasesSo… 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 = X2 4

Solubility - GasesHenry’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