Lesson eLearning

If burning 1 kg of bituminous coal releases 25 MJ of energy, how many MJ of energy are released when 150 g of coal is burned?

medium 2 marks Class 8 · Science · Coal and Petroleum
Answer
3.75 MJ

The correct answer is 3.75 MJ — Hence 3.75 MJ of energy is released.

Step-by-step solution

  1. Convert 150 g to kilograms: (150,\text{g}=0.150,\text{kg}).
  2. Use proportion: energy released per kg × mass burnt = (25,\text{MJ/kg} \times 0.150,\text{kg}).
  3. Compute (25 \times 0.150 = 3.75).
  4. Hence 3.75 MJ of energy is released.
Common mistake: Using grams directly in MJ/kg calculation

Concept tested: Energy calculation for coal

Published · How this solution was prepared and checked

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