Rates Of Reaction Flashcards
The collision theory
for a reaction to occur particles must collide with enough energy. Activation energy is the minimum energy needed by particles so that they will react when they collide
What is the activation energy?
The minimum energy needed by particles so that they will react when they collide
Increasing the size of solid particles makes the reaction…
Slower
Increasing concentration makes the reaction…
Faster
Increasing temperature makes the reaction…
Faster
Increasing pressure makes the reaction…
Faster
Adding a catalyst makes the reaction… but the catalyst is not…
Faster… unused/ unchanged
Particle size - how does it affect rate?
Larger particles have a smaller surface area.
Therefore they collide less often.
Therefore there are fewer successful collisions per second.
Therefore rate decreases
Vice Versa
Concentration- how does it affect rate?
There are more particles in a given volume.
Therefore they collide more often.
Therefore there are more successful collisions per second.
Therefore rate increases
Vice Versa
Temperature - how does it affect rate?
Particles have more energy so move faster and collide more often. More of the particles have energy greater than the activation energy.
Therefore there are a higher percentage of successful collisions per second.
Vice Versa
Pressure - how does it affect rate?
Particles are closer together so collide more often.
More successful collisions per second.
Vice Versa
Catalysts - how do they affect rate?
Provide an alternative route of lower activation energy.
More particles have energy greater than the activation energy.
Therefore more successful collisions per second.
Particle size - why do they have this effect?
Smaller particles of solid have a larger surface area so they collide more often and there are more successful collisions per second.
Concentration - why does it have this effect?
As the concentration increases there are more particles in a given volume so they collide more often and there are more successful collisions per second.
Temperature - why does it have this effect?
Collision frequency - the particles have more energy, so move faster and collide more often.
Activation energy - more particles have energy greater than the activation energy so a higher percentage of collisions are successful per second.
What is the rate of reaction?
The rate of a chemical reaction is the speed at which a reactant is used up or a product is made
