Energy cost of creating body parts from nothing but energy

What amount of energy would you need to expend to create an arm out of nothing but energy?

Of course we have $E = m c^2$ telling us the energy any amount of mass represents. Given the average of a total human male arm of $m_{\text{arm}} = 5.7\text{ kg}$ that would equal $E_{\text{Matter}} = 5.123 × 10^{17} \text{ J}$ of energy just for the matter.

The question is whether accounting for the matter is sufficient
There is still the chemical energy depending on the molecular structure. A block of graphite and a block of diamond are both just carbon, but they have different chemical energies.

I think the chemical energy is ultimately irrelevant considering the sheer magnitude of $E_{\text{Matter}} = 512.3 \text{ PJ}$ which would equal harvesting the energy of $7115.3\text{ kg}$ of Uranium-235 in a nuclear reactor.

An upper bounds calculation regarding the chemical energy of carbon as an example
Comparing the enthalpy of pure carbon (gas) and graphite (in German) with we get an energy difference $\Delta{E}$: $$H_{\text{carbon}} = 718.9 \frac{\text{kJ}}{\text{mol}}$$ $$H_{\text{graphite}} = 0 \frac{\text{kJ}}{\text{mol}}$$ $$n_{\text{C;arm}} = {m_{\text{arm}}}/{M_{C}} = 5.7\text{ kg} / 12 \frac{\text{g}}{\text{mol}} = 475 \text{ mol}$$
$$\Delta{E} = (H_{\text{carbon}} - H_{\text{graphite}} ) * n_{\text{C;arm}} = 341.4775 \text{ MJ}$$

If my calculation is even remotely correct then we are about 9 magnitudes below the energy required for just the matter. So it is easily a negligible amount of energy compared to the creation of matter.

Is there an important effect or principle that I did not account for? In my opinion what ever is to happen chemically is entirely negligible regarding the amount of energy required.

To clarify:
It is to be assumed that every atom is created in the spot it is needed and the liquid and solid matter does not need to be sorted from a blob of unsorted matter.

I am not as well versed in chemistry as in physics, but to my knowledge the numbers should be massively different (as they are in my calculation) as you do not need an extra nuclear reactor to fuel basic chemical reactions to form biochemical molecules and structures.

posted almost 6 years ago

ArtificialSoul‭

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