Rate equations and Kp Flashcards
Define the reaction rate:
The reaction rate is the change in amount of reactant or product per unit time and it’s units are moldm^-3^s-1.
What is the rate equation?
Rate = k[A]^m [B]^n
where m and n are the orders of reaction with respect to reactants A and B and k is the rate constant.
What are the orders of reaction?
If [A] changes and the rate stays the same, the order of reaction with respect to A is 0 (if A doubles/triples the rate stays the same).
If the rate is proportional to [A] then the orders reaction with respect to A is 1 (if A doubles, the rate doubles/ if A triples the rate triples).
If the rate is proportional to [A]^2 then the order of reaction with respect to A is 2 (so if A doubles, rate will be 4 times faster/ if A triples, rate will be 9 times faster).
Define the initial rate of a reaction:
The initial rate of a reaction is the rate right at the start of the reaction and can be found by calculating tangent at the time= 0.
What is the rate determining step?
Mechanisms hav one step/ a series of steps where each step can have a different rate. The overall rate is decided by the step with the slowest rate aka the rate determining step.
How do reactants in the rate equation affect the rate?
If a reactant appears in the rate equation, it must affect the rate so this reactant or something derived from it must be in the rate determining step. If a reactant doesn’t appear in the rate equation then it won’t be involved in the rate determining step.
