5 kinetics Flashcards
what is a successful collision?
when particles react
define activation energy
the minimum energy needed for a reaction to occur
what must happen for a reaction to occur?
particles must have energy that is higher than the activation energy (E>Ea)
why might a reaction occur slowly?
small number of particles have E>Ea
why do most collisions not cause a reaction?
small number of particles have E>Ea
if a reaction occurs very slowly because only a small number of particles have E>Ea, why will all particles eventually react?
molecules gain energy due to collisions
why do some molecules only have a small amount of energy?
collisions cause some molecules to lose energy
define rate of reaction
the rate of change in concentration per unit of time
what are the units for rate of reaction?
mol dm-3 s-1
what are the things that influence rate of reaction?
- temperature
- pressure
- concentration
- catalyst
- surface area
explain why temperature increase causes rate of reaction to increase
more particles have E>Ea
increases frequency of successful collisions
explain why concentration increase causes rate of reaction to increase
increase in number of particles per unit of volume
increases frequency of successful collisions
explain why pressure increase causes rate of reaction to increase
increase in number of particles per unit of volume
increases frequency of successful collisions
explain why adding a catalyst causes rate of reaction to increase
catalyst lowers Ea
so more particles have E>Ea
increasing frequency of successful collisions
explain why surface area increase causes rate of reaction to increase
increased number of reactant particles available
increasing frequency of successful collisions
