Controlling The Rate Of Reaction Flashcards
For reactants to form products what must first happen?
Must come into contact - successful collision
What happens at a high concentration?
More collisions so faster reaction
What happens when the particle size is decreased?
Creates a higher surface area so a higher chance of collision.
A minimum amount of energy is required to turn reactants into products. What is this called?
Activation energy Ea
What does increasing the temperature do?
Increases the number of particles with energy equal than or greater than Ea so speeds up reaction.
Define relative rate.
1/time
Rate of reaction is directly proportional to?
Concentration of reactants
Rate of reaction is not directly proportional to?
Temperature- a small increase in temperature results in a large increase in rate.
What does collision geometry effect?
Reaction rate
What do reaction profiles show?
How the potential energy changes as a reaction progresses.
What is enthalpy?
The name given to stored energy in chemicals.
What is the symbol for enthalpy?
H
What is enthalpy change measured in?
kJ or kJ mol-1
Enthalpy change values are negative for what type of reaction?
Exothermic
Enthalpy change values are positive for what type of reaction?
Endothermic
Activation energy is shown as what in a reaction profile?
Energy barrier
Where is an activated complex formed?
The top of the potential energy barrier
What do catalysts provide?
An alternative pathway for reactants to form products lower than the Ea
