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The standard enthalpy of formation for glucose is -2801 kJ/mol, while the standard enthalpy of formation for carbon dioxide is −393.5 kJ/mol.

If one simply examine the numbers attached to the molecules, one may have the impression that far more energy is released from the formation of glucose and thus come to understand glucose as a molecule with a low "level of energy" but this is clearly not the case as glucose is in fact combustible in most circumstance (produce carbon dioxide in the process, spontaneously)

This impression is probably inappropriate as glucose is a far larger molecule than CO2, and thus more changes is done to a greater amount of single-element reactants, but is there a better way to appreciate the amount of energy stored in a kind of molecule based on the enthalpy of combustion?

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  • $\begingroup$ To calculate enthalpy of combustion you need full equation of combustion. $\endgroup$ – Mithoron Mar 3 '16 at 0:44
  • $\begingroup$ Sorry, I believe you have misunderstood my question. I want to know if there is a way to assess the amount of energy stored in a molecule. The fact that glucose can combust to form carbon dioxide shows that there are more energy in the glucose molecule before it is converted to carbon dioxide and water. NOw that you have mentioned it, I think may be asking for an invalid comparison, maybe the energy stored in a molecule can not be calculated and compared with other species of molecules. $\endgroup$ – user289661 Mar 3 '16 at 3:51

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