CI - The rate constant and the Arrhenius equation Flashcards
How does temperature affect the rate of reaction?
Increasing temperature increases the rate of reaction.
Why does increasing temperature increase the rate of reaction?
Increasing the temperature gives the reactant particles more kinetic energy meaning that the particles speed up so they collide more often.
It also means that more reactant particles will have the required activation enthalpy for the reaction, so a greater proportion of the collisions will result in the reaction happening.
What has to happen for a reaction to happen?
The particles need to:
- Collide with each other.
- Have enough energy to react (i.e. have at least the activation enthalpy).
- Have the right orientation.
According to the rate equation, reaction rate depends only on what?
The rate constant and reactant concentrations.
What part of the rate equation does temperature affect?
The rate constant.
Why does temperature affect the rate constant?
Because it doesn’t affect the concentrations of the reactants so must affect the rate constant if it increases the rate of the reaction.
The higher the rate constant…
…the faster the rate.
A calculated rate constant for a reaction is only valid at…
…a certain temperature.
What is only valid at a certain temperature?
A calculated rate constant.
At a higher temperature, the reaction will have a higher…
…rate constant.
The reaction will have a higher rate constant at higher…
…temperature.
What does the Arrhenius equation link?
The rate constant and activation enthalpy.
What happens to the rate constant as the activation enthalpy gets bigger?
It gets smaller.
What does a large Ea mean in the Arrhenius equation?
A slow rate.
Why will the rate of reaction be slow if a reaction has a high activation enthalpy?
Not many of the reactant particles will have enough energy to react so only a few of the collisions will result in the reaction actually happening.
