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Chapter 5, Lesson 8 Multimedia

CO2 Molecule

A space-filling model of a carbon dioxide molecule, with plus signs near its carbon atom and minus signs near its oxygen atoms, indicating its areas of lower and higher areas of electron density respectively.
  • Carbon dioxide is made up of one carbon atom covalently bonded to two oxygen atoms.
  • Although electrons are shared, they are not shared equally between the carbon and the oxygen atoms.
  • The oxygen atom has a stronger pull on electrons than the carbon atom.
  • This makes the oxygen ends of the molecule slightly negative and the carbon atom slightly positive.

CO2 Dissolved in Water

Space filling models of carbon dioxide surrounded by space filling models of water, showing how their corresponding areas of electrons density make water capable of dissolving carbon dioxide.

Carbon dioxide molecules dissolve in water because the polar areas of water attract the opposite polar areas of carbon dioxide.

Solubility Curve for CO2

A solubility curve for carbon dioxide in water, showing that less carbon dioxide dissolves as temperature increases.

As the temperature increases, the number of grams of carbon dioxide that can dissolve in water decreases.

Mentos and Diet Coke Demo

  • Although the candies seem smooth, they have microscopic rough spots.
  • The carbon dioxide molecules in the soda attach to these rough spots or nucleation points on the surface of the candies.
  • The carbon dioxide builds up into bubbles and the increased pressure pushes the gas and the soda out of the bottle.