What is the chemical formula for ozone? State one beneficial effect of the ozone layer - Leaving Cert Chemistry - Question A - 2007

Chlorofluorocarbons (CFCs) are organic compounds that consist of carbon (C), fluorine (F), and chlorine (Cl). They are fully saturated alkanes where hydrogen atoms are entirely replaced with fluorine and/or chlorine atoms.

CFCs are primarily used in the production of refrigerants (such as those in fridges and air conditioning systems), as well as in fire extinguishers, and for expanded polystyrene applications including aerosols and deodorants.

CFCs contribute to ozone depletion through the following process:

1. When CFCs are released into the atmosphere, they eventually rise to the stratosphere, where they are broken down by solar UV radiation, releasing chlorine free radicals (Cl).

2. These chlorine free radicals then react with ozone ($O_3$). The reaction can be represented as: $Cl + O_3 \rightarrow ClO + O_2$

3. The chlorine monoxide (ClO) can then react with another oxygen atom: $ClO + O \rightarrow Cl + O_2$

4. This regenerates the chlorine free radical (Cl), allowing it to continue to deplete more ozone molecules, effectively leading to a chain reaction that results in significant ozone layer thinning.