1.5 Kinetics Flashcards
(10 cards)
Define rate.
The change in concentration of a reactant or product in a unit of time.
Measured in moles per dm cubed per second
What happens to rate of reaction over time?
As the reaction proceeds the rate becomes slower because there are less reactant particles left.
What must there be for a reaction to occur?
-Collisions
-correct orientation of molecules
-molecules must have enough energy to break bonds (Ea)
Define activation energy.
The minimum amount of energy that particles must have to bring about a reaction.
How does temperature affect rate of reaction?
Increasing temp increases rate
-increases no of collisions in a given time
-increases average kinetic energy of molecules
-there are MANY MORE molecules that have E greater than or equal to Ea
-more successful collisions
How does concentration affect rate of reaction?
Increasing conc increases rate
-increases no of molecules in a given volume
-increases no of collisions in a given time
(not as effective as temp as no increase in average kinetic energy of molecules)
How does pressure/volume affect rate of reaction?
Increasing pressure decreases the volume (inversely proportional)
-increasing the no of molecules in a given volume
-increases the no of collisions in a given time
How does surface area affect rate?
Increasing SA increases rate
-increases the no of collisions in a unit of time
How do catalysts affect rate of reaction?
Increase rate
-provide an alternative reaction route
-which has a lower activation energy
-therefore the number of particles with E greater than or equal to Ea will be much higher
Describe the Maxwell-Boltzmann distributions of molecular energies graphs (generally).
-Area under graph represents the total no of molecules
-Emp- most probable energy the molecules have
-Av K.E of molecules
-Ea
-the line never touches the x-axis because there is a small no of molecules with an infinite amount of energy
