Question

1. which substance is considered to be a factor affecting earths ozone layer?

ethyl alcohol
water vapor
chlorofluorocarbons
nitrogen gas

Explanation:

To determine the substance affecting Earth's ozone layer, we analyze each option:

• Ethyl alcohol (ethanol) is used in beverages, fuels, etc., and does not impact the ozone layer.
• Water vapor is a natural atmospheric component and not a major ozone-depleting substance.
• Chlorofluorocarbons (CFCs) are known ozone-depleting substances. They release chlorine atoms in the stratosphere, which break down ozone molecules ($\ce{O_3}$), leading to ozone layer depletion.
• Nitrogen gas is a major atmospheric component (about 78% of air) and does not deplete the ozone layer.

Answer:

C. chlorofluorocarbons