Consider glucose (C₆H₁₂O₆) as the energy source of anaerobic digestion and direct combustion.

a. With anaerobic digestion of glucose, methane and CO₂ is formed. With 1 kg of glucose, how much chemical energy can we get in the form of methane? In other words, what is the energy content in methane that is produced by 1 kg of glucose?

b. If we directly burn 1 kg of glucose with stoichiometric oxygen in standard condition, how much thermal energy can be obtained? Assume complete combustion products. Water in the product mixture is in the gas phase. Enthalpy of formation of glucose is -1.271 kJ/kmol.