3. Incorrect. The answer is false not true. Although the energy content of US gas is approximately 1,000 BTU/ft3; 1,000 BTU/ft3 = 8898 Kcal/m3.

First convert BTU/ft3 to Kcal/ ft3 and then Kcal/ ft3 into Kcal/m3;

1,000 (BTU/ft3) * 0.252 (Kcal/BTU) * 35.31 (ft3/m3) = 8,898.12 Kcal/m3