Question

One pound of bituminous coal contains 14,000 BTUs of energy. Suppose a coal-fired power plant needs 3,500 BTUs of heat to produce one kilowatt-hour of electricity. This plant has a 1 Megawatt output.

How much coal is required to produce one kilowatt-hour of electricity?

Answer 1

`\boxed{\text{4 oz}}`

Step-by-step explanation:

1. Energy needed

`\text{Energy} = \text{1 kWh} * \frac{\text{3500 BTU}}{\text{1 kWh}} = \text{3500 BTU}`

2. Mass of coal needed

`\text{Mass of coal} = \text{3500 BTU} * \frac{\text{1 lb coal}}{\text{14 000 BTU}} = \text{0.25 lb coal} = \textbf{4 oz coal}\\\\\text{It takes $\boxed{\textbf{4 oz of coal}}$ to produce 1 kWh of electricity}`