Reaction rate constant
k(T) is the reaction rate constant that depends on temperature.
[X] is the concentration of substance X in moles per volume of solution assuming the reaction is taking place throughout the volume of the solution. (for a reaction taking place at a boundary it would denote something like moles of X per area.)
In a single-step reaction can also be written as
Ea is the activation energy and R is the Gas constant. Since at temperature T the molecules have energies according to a Boltzmann distribution, one can expect the proportion of collisions with energy greater than Ea to vary with e-Ea/RT. A is the pre-exponential factor or frequency factor.
The units of the rate coefficient depend on the global order of reaction:
- For order zero, the rate coefficient has units of mol L-1 s-1 or mol dm-3 s-1
- For order one, the rate coefficient has units of s-1
- For order two, the rate coefficient has units of L mol-1 s-1 or mol-1 dm3 s-1
- For order n, the rate coefficient has units of mol1-n Ln-1 s-1 or mol1-n dm3n-3 s-1