CI.5 Flashcards
Finding orders using a half-life method and the link between rate equations and mechanism
When the rate is first order in respect to a particular reactant, what does the initial rate against concentration graph look like?
A straight diagonal line.
When the rate is second order in respect to a particular reactant, what does the initial rate against concentration graph look like?
A line that curls upwards.
When the rate is zero order in respect to a particular reactant, what does the initial rate against concentration graph look like?
A flat horizontal line.
What is the relationship between reaction time and rate of reaction?
The smaller the reaction time, the faster the rate and vice versa.
On a progress curve of the reaction, if the half life is constant, what order is it?
First order.
What is the slowest step of the reaction mechanism known as?
The rate determining step.
If a substance in the chemical equation is not in the rate equation, what does this reveal about the reaction mechanism?
The substance must not be involved in the rate determining step of the mechanism. They will involved in a faster step.
If a substance in the chemical equation is in the rate equation, what does this reveal about the reaction mechanism?
The substance must be involved in the rate determining step of the mechanism.
What does the orders of reaction of each substance tell you about their presence in the rate determining step?
The relative number of moles of that substance involved in the rate determining step.
Why do different steps of the reaction have different speeds?
The steps have different activation enthalpy?
What is the relationship between the speed of a reaction step and its activation enthalpy?
The larger the activation enthalpy of the step, the slower it is and vice versa.
In a multistep reaction, which one is the rate determining step?
The one with the largest activation enthalpy.
