³⁴At first it may seem non-sensical for the carbon dioxide product of this reaction to have a negative energy, until you realize the zero values given to both the carbon and oxygen reactants are entirely arbitrary. Viewed in this light, the negative heat of formation for CO₂ is nothing more than a relative expression of chemical potential energy in reference to the elements from which CO₂ originated. Therefore, a negative ΔH_f^∘ value for any molecule simply tells us that molecule has less energy (i.e. is more stable) than its constituent elements.