Figure 9 This statue of George Washington was sculpted from marble in 1918. The photograph was taken in the 1990s. The damage was done by calcium carbonate in the marble reacting with sulfuric acid in acid rain.
Acid Rain
The combustion of fossil fuels causes the acidity of rain to increase. Rain is always slightly acidic, with a pH of about 5.6, because carbon dioxide dissolves in water droplets and forms carbonic acid, H2CO3. Sulfur dioxide and nitrogen oxides released into the atmosphere also dissolve in water, forming sulfuric acid, H2SO4, and nitric acid, HNO3. The pH of rain containing sulfuric acid and nitric acid can be as low as 2.7. These acids damage stone structures like the statue in Figure 9. They also damage metal and concrete.
Section 9.1 Assessment
Reviewing Concepts
Name three forms of carbon.- What two factors can affect the properties of a hydrocarbon?
- Name the three categories of unsaturated hydrocarbons.
- Name the three main fossil fuels.
What are the two primary products of the complete combustion of fossil fuels?
What are three ways that carbon atoms can be arranged in hydrocarbon molecules?
Critical Thinking
Classifying Why isn't carbon dioxide considered an organic compound?
Applying Concepts Draw structural formulas for the two branched-chain isomers of pentane, C5H12.
Connecting Concepts
Saturation Compare the way saturated and unsaturated are used in describing hydrocarbons to how they were used in describing solutions in Section 8.2.
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