The mass percent of sulfur in a sample of coal is a key factor in the environmental impact of the coal because the sulfur combines with oxygen when the coal is burned and the oxide can then be incorporated into acid rain. Which of the following coals would have the smallest environmental impact?
a. Anthracite coal with a mass percent of sulfur of 0.5%
b. Bituminous coal with a mass percent of sulfur of 1.5%
c. Lignite coal with a mass percent of sulfur of 3.0%
d. Sub-bituminous coal with a mass percent of sulfur of 2.0%
