Kinetics Flashcards
Define the term activation energy and deduce its possible units
The minimum energy needed for a reaction to occur
kJ mol⁻¹
collision frequency
Number of collisions between particles per unit of time
collison energy
combined energy of colliding particles
Describe the movement of particles in a given system
constant random motion
Explain the meaning of the term catalyst.
a substance that increases the rate of reaction but is not used up or changed
How does the presence of a catalyst change the activation energy for a reaction?
provides an alternative reaction pathway with lower Ea
What must happen for a reaction to occur
- particles must collide
-with E greater than or equal to Ea
Define
Emp:
Ek:
E≥Ea:
Emp: most probable value for the energy of particles
Ek: kinetic energy of the particles
E≥Ea: energy greater than or equal to Ea
Why must the curve start at the origin?
No particles can have zero energy
The total area under the distribution curve represents
total number of molecules present
Why might a reaction occur very slowly?
or Why might a reaction occur very slowly?
A small number of particles have E≥Ea
Explanations for rate increases: temperature increase
-More particles have E≥Ea
-Increases frequency of successful collisions
Explanations for rate increases: concentration increase
-Increase in number of particles per unit volume
-Increases frequency of successful collisions
Explanations for rate increases: pressure increase
-Increase in number of particles per unit volume
-Increases frequency of successful collisions
Explanations for rate increases: catalyst added
-Lowers Ea
So more particles with E≥Ea
-Increases frequency of successful collisions
