Kinetics Flashcards
Define activation energy.
The minimum energy that particles need to collide with to start a reaction.
What does the Maxwell Boltzmann Distribution show?
The spread of energies that molecules of a gas or liquid have at a particular temperature.
What does the area under the MBD represent?
The total number of particles present.
Does the MBD curve meet the x axis?
No
Why doesn’t the MBD curve meet the x axis?
There is no maximum energy for molecules.
When temperature increases, what remains constant on the MBD?
The area under the curve because the total number of particles shouldn’t change.
What is a catalyst?
They speed up a reaction without getting used up by providing an alternative route with a lower activation energy.
What happens to the Ea when a catalyst is introduced?
It gets lower and more particles have more energy than the Ea.
Describe how a catalyst speeds up a reaction.
If the activation energy is lower, more particles will have energy greater than the Ea, so there will be a higher frequency of effective collisions. The reaction will be faster.
Effect of increasing surface area on rate of reaction?
Successful collisions become more frequent.
Effect of increasing temperature on rate of reaction?
At higher temperatures the energy of the particles increases. The pariticles collide more frequently and more often with energy greater than the activation energy. More collisions result in a faster reaction.
Effect of increasing concentration and pressure on rate of reaction?
At higher concentrations and pressures there are more particles per unit volume and so the particles collide with a greater frequency and there will be a higher frequency of effective collisions.
If a question mentions the doubling of concentration or rate then what should you mention?
Double the number of particles per unit volume and double the frequency of effective collisions.
What happens to the shape of the MBD when concentration increases?
It doesn’t change so Emp and mean energy don’t change.
What changes to the MBD when concentration increases?
The curves will be higher and the area under the curve will be bigger as there are more particles.
