Rate equations

• What is the order of reaction?

  The order of reaction for a reactant shows how the rate is affected by the concentration of that reactant. It can be zero, first, or second order.
• If the order of reaction is 0, the reactant concentration has no effect on the rate of reaction
• If the order of reaction is 1, then the rate is directly proportional to the concentration of the reactant. So, if the concentration of the reactant doubles, the rate also doubles.
• If the order of reaction is 2, the rate of reaction is proportional to the square of the concentration of the reactant. So, if the concentration of the reactant doubles, the rate increases by a factor of 4.
• The rate of constant (k) is the proportionality constant in the rate equation that is specific to a reaction at a given temperature. Its value depends on the reaction order and is influenced by temperature.
• As temperature increases, the rate constant (k) increases because the particles have more kinetic energy, leading to more frequent and energetic collisions.
• The Arrhenius equation shows how the rate constant (k) varies with temperature:

  • k = Ae − Ea/RT

  The rearranged equation is:

  • ln k = ln A− Ea/RT

  where Ea​ is the activation energy, R is the gas constant, T is the temperature in Kelvin