Chapter 13 · Solutions
13.1Tragedy in Cameroon
7 min · two checks
Predict
How can a lake suddenly release a deadly cloud of carbon dioxide?
The idea
- Describe gas dissolved in water as a real solution.
- Name the condition that keeps a gas dissolved.
In 1986, Lake Nyos in Cameroon released a huge burst of carbon dioxide that had been dissolved in deep water. The gas, heavier than air, flowed into valleys and suffocated people and animals. The chemistry lesson is not exotic: gases dissolve, their solubility depends on pressure, and a sudden drop in pressure dumps the gas back out. A bottle of soda is the same experiment at a harmless scale.
This chapter treats solutions as homogeneous mixtures with a solvent and one or more solutes. You will learn how solids and gases dissolve, how to state concentration so a number means an amount, and how dissolved particles change boiling, freezing, and the flow of water through membranes.
Keep these
- Dissolved gases are solutes. Pressure keeps them dissolved.
- Drop the pressure and gas solubility falls.
- A solution is a homogeneous mixture: solvent plus solute.