CHEMISTRY, KINETICS: THE STUDY OF
RATES OF REACTIONS
, The term kinetics implies action or motion. For chemical reaction, this motion is the speed at which the
reaction takes place, and by that we mean the speed at which the reactants are consumed and the
products formed.
The speed of reactions range from very rapid to extremely slow. We call the speed of reaction the
rate of reaction or reaction rate. One of the benefits of studying the rate of reaction and the factors that
control it is some insight into the mechanism of the reaction the individual chemical steps that
produce the net overall change described by the balanced equation.
Factors that Affect Reaction Rates
There are five factors that control the rate of reaction.
1. The nature of reactants- Some substances, because of their chemical bonds, just
naturally react faster than others under the same conditions
2. Ability of reactants to meet Many reactions are classified as homogeneous reactions because
they are carried out in a solution where the reactants can mingle on a molecular level. For
heterogeneous reactions, at least two phases are present, and particle size is the controlling
factor. For a given mass of reactant, the smaller the particle size, the larger the area of contact
with the other reactants in other phases, and the faster reaction.
3. Concentrations of reactants the rates of most reactions increase with increasing
reactant concentration.
4. Temperature with very few exceptions, reactions proceed faster as their temperature is raised.
RATES OF REACTIONS
, The term kinetics implies action or motion. For chemical reaction, this motion is the speed at which the
reaction takes place, and by that we mean the speed at which the reactants are consumed and the
products formed.
The speed of reactions range from very rapid to extremely slow. We call the speed of reaction the
rate of reaction or reaction rate. One of the benefits of studying the rate of reaction and the factors that
control it is some insight into the mechanism of the reaction the individual chemical steps that
produce the net overall change described by the balanced equation.
Factors that Affect Reaction Rates
There are five factors that control the rate of reaction.
1. The nature of reactants- Some substances, because of their chemical bonds, just
naturally react faster than others under the same conditions
2. Ability of reactants to meet Many reactions are classified as homogeneous reactions because
they are carried out in a solution where the reactants can mingle on a molecular level. For
heterogeneous reactions, at least two phases are present, and particle size is the controlling
factor. For a given mass of reactant, the smaller the particle size, the larger the area of contact
with the other reactants in other phases, and the faster reaction.
3. Concentrations of reactants the rates of most reactions increase with increasing
reactant concentration.
4. Temperature with very few exceptions, reactions proceed faster as their temperature is raised.
