IB Chemistry Topic 6: Kinetics

How to measure rate of reaction

mass or volume changes for gaseous reaction

change in pH for reactions involving acids or bases

change in conductivity measurements for reactions involving color changes

use of a spectrometer or colorimeter for reactions involving colour changes

collision theory

the two particles (atoms, ions, radicals or molecules) must come into physical contact with each other

they must collide in the correct orientation, so that the reactive parts of each of the two partners come into contact with each other

the reactant molecules must collide with sufficient kinetic energy to bring about the reaction

activation energy

minimum amount of energy required to bring about the reaction

Increasing the concentration of the reactants or the pressure of a gaseous reaction

the number of collisions will increase so the rate increases

increasing the temperature of the reaction

the particles will move faster so more collisions, more particles will possess activation energy so the rate will increase

decreasing the particle size of solid reacants

increases surface area of solid so more particles are able to react, increasing rate

adding a suitable catalyst

catalysts bring the reactant particles into close contact with each other, thus lower activation increasing rate