Coal has about 2% sulfur. How many kilograms
of sulfur would be emitted from coalfired
power plants in the United States in 1 yr?
(U.S. electricity production is about 0.28 ×
1012 watts, and coal has an energy content of
about 30 × 106 J/kg. Note that 1 J = 1W-sec.)
To calculate the amount of sulfur emitted from coal-fired power plants in the United States in one year, we need to follow these steps:
Step 1: Calculate the amount of coal burned in one year.
To find out how much coal is burned, we need to know the energy produced by coal-fired power plants because coal has an energy content of about 30 × 10^6 J/kg. We are given that the electricity production in the United States is about 0.28 × 10^12 watts.
Power is defined as energy per unit time, so we can use the equation:
Power = Energy / Time
In this case, the time is one year, which is 365 days or approximately 31,536,000 seconds (assuming a non-leap year).
Converting the power to energy:
Energy = Power × Time
Energy = (0.28 × 10^12 watts) × (31,536,000 seconds)
Step 2: Calculate the amount of coal burned in kilograms.
To calculate the amount of coal burned in kilograms, we need to divide the energy produced (in joules) by the energy content of coal (in joules per kilogram).
Amount of coal burned = Energy produced / Energy content of coal
Amount of coal burned = Energy / (30 × 10^6 J/kg)
Step 3: Calculate the amount of sulfur emitted.
The coal contains about 2% sulfur. To find the amount of sulfur emitted, we need to multiply the amount of coal burned by the sulfur content.
Amount of sulfur emitted = Amount of coal burned × Sulfur content
Amount of sulfur emitted = (Amount of coal burned) × 0.02
Now we can substitute the values into the equation and solve for the amount of sulfur emitted:
Amount of sulfur emitted = [(0.28 × 10^12 watts) × (31,536,000 seconds)] / (30 × 10^6 J/kg) × 0.02
Amount of sulfur emitted = 29,436 kilograms