. Because of increasing evidence of damage to the ozone layer, chlorofluorocarbon (CFC) production was banned in 1996. However, about 100 million auto air conditioners still use CFC-12 (CF2Cl2). These air conditioners are recharged from stockpiled supplies of CFC-12. If each of the 100 million automobiles contains 1.1 kg of CFC-12 and leaks 25% of its CFC-12 into the atmosphere per year, how much Cl in kilograms do auto air conditioners add to the atmosphere each yea

Chlorofluorocarbons, commonly known as CFCs, are compounds that were once widely used in refrigeration, air conditioning, foam blowing, and as propellants in aerosol spray cans. These human-made substances have gained notoriety for their role in ozone layer depletion. CFCs are stable in the lower atmosphere, allowing them to move upward and reach the stratosphere, where the ozone layer exists.

Upon reaching the stratosphere, CFCs are broken down by ultraviolet light from the sun, releasing chlorine atoms. These atoms are highly reactive with ozone (O3), leading to the breakdown of ozone molecules. This destruction process is critical because the ozone layer provides a protective shield against harmful ultraviolet radiation, which can cause skin cancer and cataracts, harm marine life, and disrupt ecosystems.

The example of CFC-12 (CF2Cl2) from automobile air conditioners is just one instance illustrating the environmental impact CFCs can have. Despite the discontinuation of production, existing reserves and leakage continue to contribute to environmental concerns.

Environmental chemistry focuses on the chemical processes occurring in the environment and the effects of human activities on the natural world. It involves the study of the sources, reactions, transport, effects, and fates of chemical species in the air, soil, and water. Moreover, environmental chemistry looks at how to mitigate negative impacts and pursue sustainable practices.

In the context of ozone depletion, environmental chemists analyze the components like CFCs and their interaction with ozone molecules, to understand the broader implications for life on Earth. Addressing such issues often requires international cooperation and regulatory actions, such as the creation of policies like the Montreal Protocol, which sought to phase out the production and use of ozone-depleting substances such as CFCs.

Understanding environmental chemistry is vital in solving problems like ozone layer depletion and in creating alternatives to harmful chemicals that preserve the functionality of applications like refrigeration without detrimental effects on the ozone layer.

Stoichiometry is a branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows chemists to predict the amounts of substances consumed and produced in a reaction, lending itself to practical applications such as calculating the environmental impact of substances like CFCs.

For example, in the exercise above, stoichiometry is used to determine the amount of chlorine released into the atmosphere from leaked CFC-12. By calculating the mass of chlorine atoms within the molecular structure of CFC-12 and equating this to the mass of leaked CFC-12, we can understand the scope of environmental impact. It involves determining the molar mass of compounds and understanding the principles of conservation of mass.

Such calculations are essential in quantitative environmental chemistry, enabling scientists and policymakers to assess pollution levels and devise strategies for the management and reduction of harmful emissions.