69 whenever organic matter is decomposed under oxygen-free(anaerobic) conditions, methane is one of the products. thus, enormous deposits of natural gas, which is almost entirelymethane, exist as a major source of fuel for home and industry.(a) it is estimated that known sources of natural gas can produce5600 ej of energy (1 ej  10 18 j). current total global energyusage is 4.0  10 2 ej per year. find the mass (in kg) of knownsources of natural gas (  h ° rxn for the combustion of ch 4  802 kj/mol)