Kinetics Flashcards
What is the rate equation for the reaction A + B = products?
rate = k(A)^m(B)^b
What is the overall order of a reaction?
(m+n). The overall order of a reaction is never usually bigger than 3.
What is k?
k is the rate constant and the units vary depending on the overall order of the reaction.
What are the units of k for an overall order of 0?
mol l^-1 s^-1
What are the units of k for an overall order of 1?
s^-1
What are the units of k for an overall order of 2?
mol^-1 l s^-1
What are the units of k for an overall order of 3?
mol^-2 l^2 s^-1
How can the rate equation for a reaction be derived?
Experimentally. Usually, a series of experiments are carried out where the initial concentrations of the reactants are varied and the initial rate of reaction for each experiment is determined.
What is the order when a reactant concentration being doubled causes the rate to double?
The reaction will be first order with respect to that reactant.
What is the order when a reactant concentration doubling has no effect on the rate?
The reaction will be zero order with respect to that reactant.
What is the order when a reactant concentration doubling causes the rate to increase by a factor of 4?
The reaction will be second order with respect to that reactant.
How can the value of the rate constant be calculated?
By substituting experimental data from any of the experiments into the rearranged rate equation:
k = rate/(A)^m(B)^n
What is a reaction mechanism?
The series of steps that are involved in a reaction.
What is the rate-determining step?
The slowest step in the reaction. It gives the overall rate of the reaction.
What does a rate equation tell us?
A rate equation tells us which species react together in the rate-determining step and how many particles of each species is involved.
