How much does it take to burn coal to get 8.1 times 10 to the seventh power of J of energy?

univerkov | July 24, 2021 | education

Initial data: Q (the amount of heat that is required to be obtained when burning coal) = 8.1 * 10 ^ 7 J.

Reference data: q (specific heat of combustion of coal) = 27 MJ / kg = 27 * 10 ^ 6 J / kg.

We express the required mass of coal from the formula: Q = q * m, whence m = Q / q.

Calculation: m = 8.1 * 10 ^ 7 / (27 * 10 ^ 6) = 3 kg.

Answer: It is required to burn 3 kg of coal.

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