Oxygen (O₂) and ozone (O₃) are forms of the same element. Because of concern about damage to the Earth’s ozone layer by CFCs, these compounds have been banned and have been replaced by other substances e.g. HCFCs. (i) Give a brief outline of the extraction of oxygen (O₂) from air. (ii) What do the letters CFC and HCFC represent? Give one common use that was made of CFCs before they were banned. (iii) What is the importance of the ozone layer?

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Oxygen (O₂) and ozone (O₃) are forms of the same element - Leaving Cert Chemistry - Question c - 2013

Question c

Oxygen (O₂) and ozone (O₃) are forms of the same element. Because of concern about damage to the Earth’s ozone layer by CFCs, these compounds have been banned and ha... show full transcript

Worked Solution & Example Answer:Oxygen (O₂) and ozone (O₃) are forms of the same element - Leaving Cert Chemistry - Question c - 2013

Step 1

Give a brief outline of the extraction of oxygen (O₂) from air.

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Answer

The extraction of oxygen (O₂) from air involves several key steps:

Purification: The air is first purified to remove impurities such as carbon dioxide and water vapour. This ensures that only the necessary components remain for extraction.
Liquefaction: The purified air is then subjected to liquefaction by lowering the temperature and increasing pressure. This process converts the gaseous oxygen into a liquid state.
Fractional Distillation: Finally, the liquefied air is separated using fractional distillation. This technique exploits the differences in boiling points among the various gases present, allowing for the isolation of oxygen.

Step 2

What do the letters CFC and HCFC represent?

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Answer

CFC stands for chlorofluorocarbons, while HCFC stands for hydrochlorofluorocarbons. These are classes of compounds previously used in various applications.

Step 3

Give one common use that was made of CFCs before they were banned.

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Answer

One common use of CFCs was as refrigerants in air-conditioning systems and refrigerators. They were also utilized as aerosol propellants in spray products and in fire extinguishers.

Step 4

What is the importance of the ozone layer?

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The ozone layer is crucial for life on Earth as it acts as a protective shield against ultraviolet (UV) radiation from the sun. This layer absorbs most of the harmful UV rays, preventing them from reaching the Earth's surface, thereby reducing the risk of skin cancer and other health issues. Additionally, the ozone layer helps to maintain the Earth's climate by influencing the temperature and weather patterns.

Oxygen (O₂) and ozone (O₃) are forms of the same element - Leaving Cert Chemistry - Question c - 2013

Worked Solution & Example Answer:Oxygen (O₂) and ozone (O₃) are forms of the same element - Leaving Cert Chemistry - Question c - 2013

Give a brief outline of the extraction of oxygen (O₂) from air.

What do the letters CFC and HCFC represent?

Give one common use that was made of CFCs before they were banned.

What is the importance of the ozone layer?

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