Lesson eLearning

If burning 1 kg of anthracite coal releases 30 MJ of energy, how many MJ of energy are released when 200 g of anthracite is burnt?

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

The correct answer is 6 MJ — Multiply the energy per kilogram by the mass: 0.2 kg × 30 MJ / kg = 6 MJ.

Step-by-step solution

  1. Convert 200 g to kilograms: 200 g ÷ 1000 = 0.2 kg.
  2. Multiply the energy per kilogram by the mass: 0.2 kg × 30 MJ / kg = 6 MJ.
Common mistake: forgetting to convert grams to kilograms

Concept tested: Energy released by coal combustion

Published · How this solution was prepared and checked

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