# Bonding energy in compounds

## Main Question or Discussion Point

I have been researching on the bonding energies of different compounds, and for example, for CO2 it is 1600kJ/mole, 1600kJ/44g, or ~36.37kJ/g of energy required to split the carbon dioxide into carbon and oxygen. Furthermore, I transformed the amount of energy required in kJ to degrees celsius, and got 845.2 Cº for splitting 44g (or 1 mole), or 19.15 Cº for splitting 1 gram of CO2. However, the latter figure, as you may have noticed, is clearly absurd, as you logically cannot split 1 gram of CO2 with such a relatively low temperature.

I clearly understand that I am following the wrong procedure, although it seems the logical one at first, until, of course you arrive at an unreasonable figure. How should I find the required temperature for splitting a certain quantity of a compound? Also, why is my procedure wrong, and what have I not understood correctly?

Finally, I have also considered using a set of ultracapacitors connected together as an option to splitting CO2, (already having considered the amount of ultracapacitors needed): for example, to achieve an energy of ~36.37kJ (to split 1 gram of CO2) I would need 20 ultracapacitors with (individually) a voltage of 2.7V and capacitance of 500 farads. Would it be possible to split CO2 using ultracapacitors, or is this procedure also wrong, and why?

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1600 kJ/mole is $1.6 \cdot 10^6 \,J/(6.02 \cdot 10^{23})= 2.7 \cdot 10^{-18} \, J/$molecule. This will only be approximate, but with $k_B=1.38 \cdot 10^{-23} \, J/K$, the temperature $T \approx 2 \cdot 10^5$ to separate the $CO_2$ molecule into atoms by thermal means. $\\$ And putting the molecule into a strong electric field, such as between capacitor plates is not likely to separate it into components. The $CO_2$ molecule is electrically neutral and only slightly polar. It would not be affected appreciably by the voltage from two capacitor plates.

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However, if the CO2 was pressurized and turned into liquid, adding an electrolyte, would it be possible to split the CO2 into its components?

Edit: is the temperature (T): 2·105 the temperature required to split 1 molecule of CO2, in degrees kelvin? In addition, I now understand that your procedure is the correct one, but why exactly is my procedure wrong, (1600kJ/44g to get energy for 1 gram and then transform ~36.37kJ to celsius: 19.15 cº (which I know is wrong)), as it seems the most logical & proper one at first hand, and how to avoid these type of procedures on other concepts?

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The calculation shows energy $E=2.7 \cdot 10^{-18}$ Joules/molecule. At a temperature of $T=200,000 \, K$, thermal energy will break most of the bonds in these molecules. That is only an approximate calculation, and each of the bond energies will actually be 1/2 of what I used above. This is only approximate, but it basically says that $CO_2$ is a very stable molecule. One way of getting $O_2$ in a process with $CO_2$ is by photosynthesis: $CO_2+H_2 O \rightarrow CH_2O+O_2$. There have recently been attempts to do this process artificially, but it hasn't yet been achieved on a large scale. See e.g. https://www.physicsforums.com/threads/breaking-down-carbon-dioxide.916913/#post-5778727