Hydrogen:

Hydrogen gas (dihydrogen or molecular hydrogen) is highly flammable and will burn in air at a very wide range of concentrations between 4% and 75% by volume. The enthalpy of combustion for hydrogen is 286 kJ/mol:

Please answer a question about this article. If the question is unanswerable, say "unanswerable". Which element has a enthalpy of combustion at 286 kJ/mol?
Hydrogen