4.3.1 - collision theory Flashcards
a chemical reaction can only happen if…..
the reactant particles collide with enough energy
what is the amount of energy particles need to react called?
activation energy
what does the overall rate of a reaction involving millions of particles depend on?
- collision frequency
- percentage success
what common factors affect the rate of reaction?
- solid surface area
- solution concentration
- temperature
- catalysts
how do you calculate the rate
rate = collision frequency x % success
higher solid surface area increases the rate because:
- more of the solid is exposed to the other particles
- so the collision frequency is higher
- so there are more successful collisions per unit time
higher solution concentration/gas pressure increases rate because:
- there are more particles per unit volume
- so the collision frequency is higher
- so there are more successful collisions per unit time
higher temperature increases rate because:
- the particles have more kinetic energy
- so the percentage of collisions with enough energy is higher
- so there are more successful collision per unit time
catalysts increase rate because:
- they provide an alternative route with a lower activation energy
- so the percentage of collisions with enough energy is higher
- so there are more successful collisions per unit time
how can increasing concentration be accomplished?
dissolving more solute particles
how can increasing pressure be accomplished?
making the reaction vessel smaller
how do you increase temperature?
heating
how can you increase the surface area of a solid
grind or crush it up
