PHYSICAL - KINETICS Flashcards
what is collision theory
Reactions can only occur when collisions between particles take place with sufficient energy
Define activation energy
Minimum amount of energy that particles need to collide with to start a reaction
Maxwell - Boltzmann curve Why do some have low energies
As some collisions cause some particles to slow down
MBD - Why does it go through the origin
Because there are no molecules with zero energy
MBD - What is EmP
The most probable energy
MBD - What does the area under the curve represent
The number of particles present
MBD - why doesn’t the energy distribution curve meet the X axis
Because there is no maximum energy for molecules
Describe temp increase - MBD
As temp increase distribution shifts towards more molecules having higher energies
EmP and mean energies shift towards higher energy values but the molecules at the higher energy values decreases
The area under the curve remains the same as the number of particles is constant
What happens at higher temperatures to particle energy
The particle energy increase as they collide more frequently and more often at energies greater than the activation energy
Define rate of reaction
The change in concentration of a substance in unit time
Increasing concentration and pressure
At higher concentration and pressures there are more particles per unit volume so there is a greatly frequency of collisions and therefore a higher frequency of successful collisions
Area under curve increases as there are more particles
Effect of catalyst
Increase the rate of reaction without being used up by providing an alternative reaction pathway
