Question

How many kg of coal would be required to produce 1,000 BTU?

Answer 1

1 kg coal = 15,000-27,000 kilojoule
= 15-27 million joule
1 BTU = 1054–1060 joule
1000 BTU = 1 054 000 - 1 060 000 joule
now divide 1054000 by 15000000 = 0.07 kg = 70 g
then divide 1060000 by 27000000 = 0.04 kg = 40 g

So 40-70 grams of coal would be required to produce 1000 BTU