Collision Theory Flashcards
Three factors in collision theory that must happen for reaction to occur
Particles must collide, must have sufficient energy and must collide with the correct orientation
Why does increasing concentration increase rate
More particles available to react in same volume so particles closer together meaning more frequent collisions
What type of substance does concentration apply to
Solutions
Why does increasing pressure increase rate
Means more particles per unit volume so particles closer together leading to more frequent collisions
What type of substances does pressure apply to
Gases
Why does increasing temperature increase rate
Increases KE of reacting particles meaning they move more quickly so collide more frequently and greater number of particles have sufficient activation energy meaning more successful and frequent collisions
Why does increasing SA of solid increase rate
Increases surface area exposed to reacting chemicals in the same volume meaning more frequent collisions
Role of catalysts
Provide alternative reaction pathway with lower activation energy so increase rate of reaction without being used up itself
What is activation energy
Minimum amount of energy needed by particles in order to successfully react
Y axis on Boltzmann distribution
Number of molecules
X axis on Boltzmann distribution
Kinetic energy
How is Boltzmann distribution skewed
Peak to left
What is peak of Boltzmann distribution
Mean energy
What happens to Boltzmann distribution if catalyst added
Activation energy moves to lower energy, means more particles have sufficient energy to react
Does line to right of peak on Boltzmann distribution touch the x axis
No it never does
What happens to Boltzmann distribution when temperature is increased
Increases amount of energy particles have so curve moves to the right however we have no extra particles so peak of curve gets lower to allow move to right. Means more particles have sufficient energy to react
What happens to Boltzmann distribution when concentration increased
Amount of energy that particles have stays the same so the curve doesn’t move however extra particles have been added so curve gets higher, means more particles with sufficient energy
What is a transition state
The state of reacting particles when they are at the top of the activation energy barrier for a reaction step, exist for such a brief moment that they cannot be detected or isolated
