Hello.
I wanna ask you 'Rate constant (k)'.
I read a paper about the synthesis of NOx.
At that time, I was curious about the relation between k and reaction rate?
Here, (7) reaction shows 10^-11 cm^6 molecule^-1s^-1 and (8) reaction shows 10^-32 cm^6 molecule^-1s^-1, respectively.
And, it was indicated that (8) reaction for NO2- formation is predominant even though a lower k than (7) reaction.
Finally, what I want to ask is the relation between k and reaction rate because I thought that a higher k means a higher reaction rate.
I attached some pics.
Thank you so much.
ref: Peng, Peng, et al. "In situ plasma-assisted atmospheric nitrogen fixation using water and spray-type jet plasma." Chemical communications 54.23 (2018): 2886-2889.
it is in the simplest form z speed of reaction. The rate constant is a proportionality factor in the rate law of chemical kinetics that relates the molar concentration of reactants to reaction rate. It is also known as the reaction rate constant or reaction rate coefficient and is indicated in an equation by the letter k.
A nice explanation is here:
https://en.wikipedia.org/wiki/Reaction_rate_constant
or here:
https://www.thoughtco.com/reaction-rate-constant-definition-and-equation-4175922
The rate constant is the number of reactions per second divided by the product of concentrations of the reactants. The unusual units mean if the rate constant is k=1e-11 cm^6/molecule/sec, concentration of reactant 1 is n1=1e14 cm^-3 and reactant 2 is n2 = 1e12 molecules/cm^3, then the rate of reactions, N = k*n1*n2 = 1e15 s^-1. In a three-body reaction, k_3 has units of cm^-9/molecules/sec.
Say the reaction goes like
A —-> P
Where A is the reactant and P is the product
So the rate of the reaction (the speed with which it proceeds) is
Rate= k* [A]
Here k is the rate constant and [A] is the molar concentration of the reactant.
Rate of reaction is directly proportional to the conc of A, where k (the rate constant) is the proportionality constant.
Gurkanwal Kaur Sekhon David Cope Przemyslaw Wachulak Thank you for the reply.
Well.. I'm so sorry if I couldn't understand or express well...
But, What I want to ask is that even though k is lower, the reaction can be higher as indicated in the paper. Is it right?
Yes, since the reaction rate depends upon the product of rate constant and concentrations, the reaction rate can be greater if the appropriate concentrations are greater, even though the rate constant itself is lower.
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