1
CHEM1048A
Chemistry I
Chemical Kinetics
Acknowledgement of material:
Brown et al, Chemistry: The Central
Lecturer: Dr M. Maphupha
Science, Global Edition, 15thEdition. Office: C505, Humphrey Raikes Building
Staff from the Wits School of Email:
Chemistry
,2
Kinetics
➢ Kinetics is the study of how fast (rate) chemical reactions occur.
➢ Reaction rate refers to how quickly a chemical reaction takes
place.
➢ Besides information about the speed at which reactions occur,
kinetics also give us details about the mechanism of a reaction
(exactly how the reaction occurs).
➢ There are 4 important factors which affect rates of reactions:
▪ Physical state
▪ Concentration
▪ Temperature
▪ Catalyst
➢ Goal: to understand chemical reactions at the molecular level.
,3
Factors that affect reaction rates
Physical State of the Reactants
▪ In order to react, molecules must come in contact with each other.
▪ The more homogeneous the mixture of reactants, the faster the
molecules can react.
, 4
Factors that affect reaction rates
Concentration of Reactants
▪ An increase in reactant concentration is likely to increase the rate
of reaction, due to the increase in the frequency of collisions
between reactant molecules.
21% O2 100% O2
burning steel wool in air Burning steel wool in pure oxygen
© 2018 Pearson Education, Inc.
CHEM1048A
Chemistry I
Chemical Kinetics
Acknowledgement of material:
Brown et al, Chemistry: The Central
Lecturer: Dr M. Maphupha
Science, Global Edition, 15thEdition. Office: C505, Humphrey Raikes Building
Staff from the Wits School of Email:
Chemistry
,2
Kinetics
➢ Kinetics is the study of how fast (rate) chemical reactions occur.
➢ Reaction rate refers to how quickly a chemical reaction takes
place.
➢ Besides information about the speed at which reactions occur,
kinetics also give us details about the mechanism of a reaction
(exactly how the reaction occurs).
➢ There are 4 important factors which affect rates of reactions:
▪ Physical state
▪ Concentration
▪ Temperature
▪ Catalyst
➢ Goal: to understand chemical reactions at the molecular level.
,3
Factors that affect reaction rates
Physical State of the Reactants
▪ In order to react, molecules must come in contact with each other.
▪ The more homogeneous the mixture of reactants, the faster the
molecules can react.
, 4
Factors that affect reaction rates
Concentration of Reactants
▪ An increase in reactant concentration is likely to increase the rate
of reaction, due to the increase in the frequency of collisions
between reactant molecules.
21% O2 100% O2
burning steel wool in air Burning steel wool in pure oxygen
© 2018 Pearson Education, Inc.
