simple collision theory Flashcards
what is meant by the term ‘rate’?
the change of concentration or amount of product produced over time
how do you calculate rate of reaction?
(reactants used / product made) / time
what is collision theory?
particles must collide in the right direction and have the minimum amount of kinetic energy for a reaction to take place
what is ‘activation energy’?
the minimum amount of energy required to break the bonds of the reactants
describe the effect of concentration on rate of reaction?
increased concentration
particles are closer together
more frequent successful collisions
increased rate of reaction
describe the effect of temperature on rate of reaction?
- increased temperature
- more molecules have more than the activation energy
- particles move around more
- more frequent successful collisions
- increased rate of reaction
describe the effect of pressure on rate of reaction?
- increased pressure
- more particles per unit volume
- more frequent successful collisions
- increased rate of reaction
describe the effect of catalysts on rate of reaction
- provides an alternative pathway for reaction with a lower activation energy
- more particles have the activation energy
- increased rate of reaction
what does it mean if a reaction is exothermic?
reactants have more energy than products
energy is released
what does it mean if a reaction is endothermic?
products have more energy than reactant
energy is taken in
in which direction does the activation energy arrow go on a reaction profile?
from reactants to top of activation curve
in which direction does the enthalpy arrow go on a reaction profile?
from reactants to products
what does the increase in activation energy curve show on a rates graph?
molecular bonds stretch due to an increase in kinetic energy
what does the activation energy curve peak show on a rates graph?
bonds having enough energy to break
describe the energy in endo and exothermic reactions
endothermic = energy is absorbed
exothermic = energy is released
