REACTION KINETICS
1.1 Basics of kinetics
The rate of reaction refers to the change in the amount or
-3 -1
concentration of a reactant or product per unit time (mol dm s )
The rate of reaction is the gradient when a graph for the reaction
is plotted.
The proportionality constant k is the gradient of the graph and is also called the rate constant
m n
Rate of reaction = k [A] [B] [A] and [B] = concentrations of reactants m and n = orders of the reaction
Determining order of reaction
Order of reaction is the power to which a
concentration of a reactant is raised in the rate
equation. It can only be determined experimentally not
using stochiometric equation.
Half-life
The half-life (t1/2) is the time taken for the concentration of a reactant to become half of its initial value
the power to which the concentration of a reactant is raised in the rate equation
In zero-order reaction the successive half-life decrease with time (less time required to half)
In first-order reaction the half-life is constant because it’s independent of the concentration of reactants
o Despite the concentrations of the reactants decreasing during the reaction
o The amount of time taken for the concentrations of the reactants to halve will remain the same
throughout the reaction
In second-order reaction the half-life increases with time (more time required to half)
, 1.2 Rate constant calculations
Rate constant with initial rate
Rate constant with half-life
1.1 Basics of kinetics
The rate of reaction refers to the change in the amount or
-3 -1
concentration of a reactant or product per unit time (mol dm s )
The rate of reaction is the gradient when a graph for the reaction
is plotted.
The proportionality constant k is the gradient of the graph and is also called the rate constant
m n
Rate of reaction = k [A] [B] [A] and [B] = concentrations of reactants m and n = orders of the reaction
Determining order of reaction
Order of reaction is the power to which a
concentration of a reactant is raised in the rate
equation. It can only be determined experimentally not
using stochiometric equation.
Half-life
The half-life (t1/2) is the time taken for the concentration of a reactant to become half of its initial value
the power to which the concentration of a reactant is raised in the rate equation
In zero-order reaction the successive half-life decrease with time (less time required to half)
In first-order reaction the half-life is constant because it’s independent of the concentration of reactants
o Despite the concentrations of the reactants decreasing during the reaction
o The amount of time taken for the concentrations of the reactants to halve will remain the same
throughout the reaction
In second-order reaction the half-life increases with time (more time required to half)
, 1.2 Rate constant calculations
Rate constant with initial rate
Rate constant with half-life
