Chemical Properties of Carbon Dioxide
Carbon dioxide is a simple three atom molecule (see below). Despite its simplicity, it has unique properties which causes it to have a profound impact on life. The picture below is one way of presenting a 3-dimensional view of a carbon dioxide molecule.
Figure 1. A Model of the Carbon Dioxide Molecule. The red spheres represent oxygen atoms and the black sphere represents the carbon atom. Note that the molecule is linear and the carbon is in the middle.
Click here for another representation of this molecule and other molecules of atmospheric gases.
The chemical properties of carbon dioxide that affect life on earth are:
-
Carbon dioxide dissolves very well in water.
-
After carbon dioxide dissolves in water, it rapidly forms a new compound. This reaction is reversible.
-
The new compound formed from carbon dioxide and water is acidic.
-
Molecules of carbon dioxide can absorb heat from solar energy and trap the heat in the atmosphere.
-
Carbon dioxide gas is very dense and will collect near ground level.
-
Carbon dioxide gas is not flammable and is used to put out fires.
A chemist would represent the first three properties with chemical equations:
This means that a molecule of carbon dioxide could dissolve in water (like the ocean). The molecule could then react with a water molecule and form the acid H+. The equation also means that an acid H+ could react with HCO3- and end up as carbon dioxide in the air.
There are a lot of chemical properties that chemists have measured for thousands of chemical compounds. To get an idea of the magnitude of these measurements, view the web site created by the National Institute of Standards and Technology. http://webbook.nist.gov/chemistry/name-ser.html.en-us.en
Classroom Activities
The fact that carbon dioxide gas is very dense and inflammable allows for a very good classroom demonstration. Click the URL for directions. http://educ.queensu.ca/~scihttp://educ.queensu.ca/~science/main/concept/gen/g02/G02DESU1.htmlence/demos/jlgdemo.htm
Carbon dioxide is easy to generate in the classroom. Teachers often use this property to make other activities such as rockets. http://educ.queensu.ca/~science/main/concept/chem/c06/c06dekk7.html