The Collision Theory and Activation EnergyExplaining how and why factors affect reaction ratesThe Maxwell-Boltzman apparatus• Maxwell and Boltzman performed an experiment to determine the kinetic energy distribution of atoms• Because all atoms of an element have roughly the same mass, the kinetic energy of identical atoms is determined by velocity (KE= ½mv2)The Maxwell-Boltzman distribution• The resulting disk looks like this:Basically, if we plot the intensity of the dots on a graph we get a graph of fraction of atoms/molecules vs. kinetic energy:Fraction of moleculesKinetic energy ⎯→Molecules hit disk firstMolecules hit disk lastWhy is the graph skewed?• This curve is characteristic of all molecules• The curve is elongated due to how atoms collide, and to the units of the graph• Recall all particles are in motion. An average speed will be reached.• The graph is skewed because 0 is the lower limit, but theoretically there is no upper limitSame data, different axes. E.g. v=1, KE=1
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