Posted by alf on .
How much heat energy is required to raise the temp of 5 kilograms of coal from 20 degree celsius to 220 degrees celsius?
You need the specific heat of coal to answer that question, and that depends somewhat upon the type. Did they mention a value to use? This article:
AIChE Journal Volume 31, Issue 10 , Pages 1714 - 1717
mentions a specific heat value of
C = 1.05 kJ/Kg C
That would make the heat required
(1.05 kJ/kg C)* 5 kg * 200 C = 1,050,000 kJ
That is closest to the last of your choices.