18.1 Orders, rate equations and rate constants

• Rate of reaction is the change of concentration of a reactant or a product in a given amount of time
• Orders show how rate is affected by concentration
• If a substance has zero order, the rate is not affected by concentration
• If a substance has first order, the rate changes by the same factor as the concentration change
• If a substance has second order, the rate changes by the same factor as the concentration range raised to the power 2
• Overall order of a reaction is the sum of the individual order of the reactants
• The rate equation shows the link between rate, concentration and orders
• The rate constant k is the proportionality constant in the rate equation
• In the rate equation, the concentration of the reactants are raised to the power of their order
• The rate equation can be rearranged to find the value of k