Question

If an average \(\mathrm{O}_{3}\) molecule "lives" only \(100-200\) seconds in the stratosphere before undergoing dissociation, how can \(\mathrm{O}_{3}\) offer any protection from ultraviolet radiation?

Short answer

In conclusion, the continuous cycle of ozone formation and dissociation in the stratosphere ensures sufficient protection from harmful ultraviolet radiation, despite the short lifespan of individual ozone molecules. Ozone molecules (O3) act as a shield by absorbing UV radiation and dissociating into oxygen molecules (O2) and atoms (O), which then reassemble into new ozone molecules through further reactions with UV radiation. This cycle maintains an effective barrier against UV radiation, even with the short lifetimes of individual ozone molecules.

Step-by-step solution

Ozone (O3) is formed through a series of reactions between oxygen (O2) molecules and oxygen atoms (O). When an oxygen molecule (O2) absorbs ultraviolet (UV) light, it splits into two oxygen atoms (O). These atoms can then react with other oxygen molecules (O2) to form ozone (O3). #Step 2: Understand the Ozone Dissociation Process#

Ozone molecules (O3) are unstable and can be easily broken down by absorbing UV radiation. When this happens, the ozone molecule (O3) dissociates into an oxygen molecule (O2) and an oxygen atom (O). #Step 3: Explain the Ozone-UV Protection Cycle#

The continuous process of ozone formation and dissociation creates a protective cycle in the stratosphere. When ozone molecules (O3) absorb UV radiation, they protect Earth's surface from harmful UV rays by preventing them from reaching the ground. At the same time, the dissociation of ozone back into oxygen molecules (O2) and oxygen atoms (O) allows for more ozone to be formed through new reactions between oxygen molecules and atoms. This continuous cycle ensures that there is always a sufficient amount of ozone in the stratosphere to protect Earth from UV radiation, even though individual ozone molecules may have a short lifespan. #Step 4: Summarize the Ozone-UV Protection Mechanism#

In conclusion, even though individual ozone molecules (O3) have a short lifespan in the stratosphere, the continuous cycle of ozone formation and dissociation ensures that there is always enough ozone present to protect Earth from harmful ultraviolet radiation. The ozone layer acts as a shield by absorbing UV radiation, dissociating into oxygen molecules (O2) and atoms (O), and then reassembling into new ozone molecules through further reactions with UV radiation. This cycle ensures that the ozone layer remains an effective barrier against UV radiation despite the short lifetimes of individual ozone molecules.