1.1 What is Chemistry?

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

FIGURE 16.8

Illustration of pressure effects on gas sol-

ubility.

If we solve the Henry’s Law equation for the molar solubility, we get the following useful relationship:

c=kρH

Example 16.7

What are the molar solubilities of oxygen gas and nitrogen gas in pure water at 298 K and 1 atm of pressure? Which
gas is more soluble under these conditions?

c

O 2

=

1 atm

756 .7 atm·mol−^1 L

= 0 .00132 mol/L

= 1 .32 mM

c

N 2

=

1 atm

1600 .atm·mol−^1 L

= 0 .000625 mol/L

= 0 .625 mM

Oxygen gas is more soluble under these conditions. A saturated solution of O 2 would have a concentration of 1.32
mM, whereas a saturated solution of N 2 would have a concentration of 0.625 mM.

Lesson Summary

• Solubility describes the degree to which a solute will dissolve in a particular solvent.


• Water is a common solvent for dissolving various solids, liquids, and gases.


• The solubilities of solids and liquids are commonly expressed as grams of solute that can be dissolved by 100
  g of water at a specified temperature.