Factors affecting
Reaction Rates
GRADE 10
Svante Arrhenius
Swedish scientist who
has suggested that
particles must posses a
certain amount of kinetic
energy in order to react

Svante Arrhenius [1]
Energy Diagram
and Activation
Energy
Energy Diagram

use to analyze
the changes in
energy that
occur during a
chemical
reaction
Sample Energy Diagram [2]
Energy Diagram and Activation Energy
Activation Energy
is the energy
required to initiate
a reaction and
force the
reactants to form
the activated
complex.

Energy Diagram of Endothermic and Exothermic Reaction [3]
Collision Theory
The Collision theory
explains how collisions
between reactant
molecules may or
may not result in a
successful chemical
reaction.
Collision theory, Ineffective and effective collision [4]
Collision Theory

Based on the theory, not all collisions result in a chemical
reaction and formation of the products. Effective collisions
between molecules, that results in the formation of
products, only occur when the following two conditions are
met ;
1)
the colliding molecules posses a minimum kinetic energy known as the
activation energy, to start a chemical reaction
2)
the reactant molecules are in the correct orientation when they collide
Factors affecting Reaction Rates
A. Particle Size or Surface Area
For solid reactants, increasing the surface area, increases the number of
particles that are exposed and available to react, and as result there is an
increase in frequency of the collisions and thus possible increase in the rate of
the reaction.
B. Temperature of the Reaction
When the temperature increases the kinetic energy of particles also
increases, this results in an increase in particle collisions and a greater portion
of these collisions will the energy required to react.
Factors affecting Reaction Rates
C. Use of Catalyst
A catalyst provides an
alternative path for the reaction,
that has a lower activation energy.
This only means that colliding
particles need less energy in order
for them to react.
Energy diagram of a reaction, with and without a catalyst [5]
Factors affecting Reaction Rates
D. Concentration of Reactants
Increasing the concentration of the reactants, increases the number of
particles available to react, thus increasing the rate of the reaction.
E. Pressure of the Reaction
In gases, increasing the pressure of the reaction forces the particles to
move closer, which then results to an increase in the frequency of collisions,
therefore increasing reaction rates.
References :
[1] https://upload.wikimedia.org/wikipedia/commons/6/6c/Arrhenius2.jpg
[2] http://www.tmcleod.org/Level1/basicpotentailenergydiagram.png
[3] Chemical Reactions and Energy
http://data.allenai.org/tqa/chemical_reactions_and_energy_L_0785/
[4] Collision Theory of Reaction Rate
https://files.askiitians.com/cdn1/images/201498-123317887-252-14.23.jpg
[5] FACTORS THAT AFFECT RATES OF REACTION
https://schoolworkhelper.net/factors-that-affect-rates-of-reaction/
[6] Making Reactions Faster: Factors Affecting Rates of Reaction
https://www.compoundchem.com/2016/02/17/rate-of-reaction/