I am curious about to know the rate of chemical reaction in space (in zero gravity). I searched it on internet and I got few answers ended with complex mathematical equetions which are out of my range (as I am organic student).
Whether absence of gravity will increase or decrease the rate of reaction, or we need catalyst for every reaction???
Hi Shrikant, In classical theory Total energy equals to Kinetics energy + Potential energy....so in vaccum condition, it means zero gravity , we avoid the effect of gravity (or potential energy). However, in material/compound/molecules/atoms, there is still an interaction (nuclear, electron in atoms and atom to atom in molecule), just said microgravity (?)...In kinetic reaction without gravity, it means the total energy is totally used for the movement of molecules (in one direction or kinetics). As far as we know kinetic reaction is affected by concentration of reactants, temperature, pressure, andcatalyst . We have never mentioned gravity factors. So theoritically (simplification), since the energy content is only used to kinetics or to overcome the energy barrier of reaction, the reaction is going to be faster (of course, one has to consider the exothermic and endothermic situation). The need of catalyst in the reaction is dependent on the condition (energy barrier, temperature, and other). It means we can not generalize it whether need or not catalyst. Experimentally, in my opinion is not simple since the characteristics of materials (or phases) are different.
A change in gravity, form 1G to 0G, will not have any effect on reaction rates: the interactions among molecules, at molecular scales are MUCH stronger than the gravity forces. You can do some simple calculations to check this. Even dispersion long range interactions are larger.
To me, a reaction being performed in space will be the same as asking about a reaction being performed in a vacuum. In heterogeneous catalysis, there are many reactions performed through in situ techniques (real time analysis performed in vacuum) that are comparable to reactions at atmospheric pressure, since in catalysis we are focused on turnover frequency (conversions per unit time per catalytic site).
Other things to consider would include the design of the reactor system. Above, I just described something deliberately performed in a vaccum. You can pressurize a reactor vessel easily in space/vacuum to replicate atmospheric pressure, and it would be similar. It's everything outside of the reactor that you have to consider.
It seems to me that if the reaction is stirred, right here on Earth, then gravitational effects would be negligible compared to those from the stirrer bar. So there may not be any difference in the reaction if it is performed under zero-G. However, without stirring, thermal effects will certainly be different. Under gravity, lower density warmed material would rise, so thermal-driven circulation may speed the rxn by providing mass transport. This (I am guessing) would not occur under zero-G. Consequently, in space a reaction might have a limited rate.
This is why conditions need to be defined, otherwise we will just be making all sorts of assumptions that in the end, the answer is so vague that it is completely dependent on the set conditions. A pressurized plug flow reactor used for a gas phase reaction would be the same in space and on earth if the pressure was the same.
We have to pay attention to chemical oscillation and symmetry braking at edge of chaos . We have to shift our traditional paradigm to find answer .
Gravity can change the rate of reaction for chemical oscillation at the edge of chaos .
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