The following formulas give the enthalpy, when Coal and Methane react with oxygen:

C+O₂->CO₂+394 kJ/mol, 12 gram C gives 44 gram of CO₂+394 kJ

CH₄+ O₂->CO₂+2H₂O+891 kJ/mol, 16 gram CH₄ gives 44 gram of CO₂+891kJ

a) Calculate the heating value of Coal and Methane in MJ/kg and in kWh/kg.

b) Calculate the amount of CO₂ which is produced per kWh for Coal and Methane. Give it in kg/kWh.

c) Methane is considered to be a 35 times stronger greenhouse gas than carbon dioxide. How is this explained?