Question

Fill in the blanks below with the correct vocabulary word or words. Chlorofluorocarbons are dangerous because they destroy the __________.

Short answer

ozone layer

Step-by-step solution

Understanding Chlorofluorocarbons

Chlorofluorocarbons (CFCs) are a type of chemical compound that was commonly used in refrigeration, air conditioning, foam blowing, and as an aerosol propellant. Understanding their chemical properties and uses helps to comprehend why they are harmful to the environment.

Identifying Environmental Impact

CFCs, when released into the atmosphere, rise up into the stratosphere where they encounter ultraviolet (UV) radiation. This radiation breaks down the CFC molecules, releasing chlorine atoms.

Recognizing the Ozone Layer

The ozone layer is a region in Earth's stratosphere that contains a high concentration of ozone (O3) and protects living organisms by blocking harmful ultraviolet rays from the sun.

Understanding Interaction with the Ozone Layer

Chlorine atoms released from CFCs react with ozone molecules, causing them to break apart. This reaction depletes the ozone layer over time.

Drawing the Conclusion

Based on the harmful chemical reactions, CFCs are primarily responsible for the destruction of the ozone layer. Therefore, the missing vocabulary word should describe the primary environmental damage caused by CFCs.

Key concepts

Chlorofluorocarbons

Chlorofluorocarbons, commonly known as CFCs, are man-made chemical compounds that consist of chlorine, fluorine, and carbon. They were once widely produced for use in air conditioning, refrigeration systems, foam production, and as propellants in aerosol sprays.
CFCs are stable and non-flammable, which made them a popular choice in various applications.
However, their stability also means that they do not break down in the lower atmosphere and can persist for a long time. When CFCs make their way up to the stratosphere, they cause significant environmental damage, leading to crucial issues like the depletion of the ozone layer, which protects living organisms from harmful ultraviolet radiation.

Stratosphere

The stratosphere is the second major layer of Earth's atmosphere, lying above the troposphere and below the mesosphere. It extends from about 10 kilometers to 50 kilometers above Earth's surface.
The upper stratosphere houses the ozone layer, which is vital for filtering out most of the sun's severely damaging ultraviolet radiation. Here is why the stratosphere is important:

• Temperature increases with altitude here because of the absorption of UV radiation by ozone.
• It contains the ozone layer that protects life on Earth.

Understanding the stratosphere's position and role is key to realizing how substances like CFCs can have such a dramatic environmental impact.

Ultraviolet Radiation

Ultraviolet (UV) radiation is a form of energy emitted by the sun. It has wavelengths shorter than visible light but longer than X-rays, falling within the range of 100 nm to 400 nm.
UV radiation is categorized into three types: UVA, UVB, and UVC. While UVC is absorbed by the ozone, UVB and some UVA reach the Earth's surface. Key points about UV radiation include:

• Exposure to excessive UV radiation can lead to skin damage, eye problems, and immune system issues.
• The ozone layer serves as a protective barrier, reducing the amount of UV radiation that reaches the Earth's surface.

Understanding UV radiation helps in grasping the significance of preserving the ozone layer.

Environmental Impact

The environmental impact of chlorofluorocarbons primarily revolves around their role in ozone layer depletion. Ozone depletion results from CFCs released into the atmosphere as they eventually make their way to the stratosphere.
Once there, they release chlorine atoms upon exposure to ultraviolet radiation. This chlorine reacts with ozone molecules, destroying them. The decline of the ozone layer can lead to several harmful effects:

• Increased UV radiation reaching Earth, resulting in health issues such as higher rates of skin cancer and cataracts.
• Adverse effects on animals and marine ecosystems, affecting food chains and biodiversity.
• Potential impacts on the climate by altering the Earth's radiation balance.

Addressing CFC use and advocating for environmentally friendly alternatives are crucial measures to mitigate these impacts.