CK-12-Chemistry Intermediate

http://www.ck12.org Chapter 16. Solutions

Substitute into Henry’s law and solve for S 2.

Step 2: Solve.

S 2 =

S 1 ×P 2

P 1

=

0 .745 g/L× 4 .50 atm

1 .00 atm

= 3 .35 g/L

Step 3: Think about your result.

The solubility is increased to 4.5 times its original value, which makes sense for a direct relationship.

Practice Problem

1. The solubility of a gas is 1.67 g/L at a pressure of 1230 mmHg. At what pressure will the solubility be 1.12
   g/L?

Lesson Summary

• Solutions can consist of solutes and solvents that are solids, liquids, or gases.


• The rate at which a solid solute dissolves in a liquid solvent increases when the surface area of the solute is
  increased, the mixture is agitated, or the temperature is raised.


• The maximum amount of solute capable of dissolving in a solvent is called its solubility. Solutions can be
  unsaturated, saturated, or supersaturated, depending on the amount of solute dissolved relative to its solubility
  at the given temperature.


• Solubility is dependent on temperature. For solids, solubility generally increases with an increase in tempera-
  ture. For gases, solubility decreases with an increase in temperature.


• Henry’s Law describes the direct relationship between the solubility of a gas in a liquid and the pressure of
  the gas.

Lesson Review Questions

Reviewing Concepts

1. What determines how fast a substance will dissolve in a given solvent?


2. What is the requirement for reaching solution equilibrium?


3. What are two things that you could do to change an unsaturated solid/liquid solution into a saturated solution?


4. A given solution is clear and colorless. A single crystal of solute is added to the solution. Describe what
   happens in each of the following situations.
   a. The original solution was saturated.
   b. The original solution was unsaturated.
   c. The original solution was supersaturated.


5. Explain how a supersaturated solution must be prepared.


6. Under which set of conditions is the solubility of a gas in a liquid the greatest?
   a. low temperature and low pressure
   b. low temperature and high pressure