U3-1-1 - Collision Theory and Relative Rate Flashcards
Part of the Controlling the Rate topic from Unit 3 of Higher Chemistry, Chemistry in Society
Why could a high reaction rate be a problem?
Could cause thermal runaway/explosions
Collision theory states that for a reaction to occur, reactant particles must collide with ________ and high enough energy.
Collision theory states that for a reaction to occur, reactant particles must collide with correct geometry and high enough energy.
Why does increasing concentration/pressure increase reaction rate?
The number of particles in a given volume increases, so the chance of collisions increases.
Why does increasing temperature increase reaction rate?
Kinetic energy of the particles increases, so the chance of collisions increases AND more collisions will have high enough energy.
Collision theory states that for a reaction to occur, reactant particles must collide with correct geometry and ________.
Collision theory states that for a reaction to occur, reactant particles must collide with correct geometry and high enough energy.
(high enough to overcome the activation energy)
Why does reducing particle size increase reaction rate?
It increases the surface area.
(Collisions can only happen at the surface, so more surface = more collisions.)
When is relative rate more suitable than average rate?
When no measurable change (e.g. volume change or mass loss) can be observed.
Formula for relative rate
If time is measured in s, what will be the units for relative rate?
s–1
Reciprocal seconds
