Catalyst: A substance that speeds up a reaction without being consumed
Enzyme: A large molecule (usually a protein) that catalyzes biological reactions.
Homogeneous catalyst: Present in the same phase as the reacting molecules.
Heterogeneous catalyst: Present in a different phase than the reacting molecules.
Lowering of Activation Energy by a Catalyst
Catalysts Increase the Number of Effective Collisions
Step #1: Adsorption and activation of the reactants.
Carbon monoxide and nitrogen monoxide adsorbed on a platinum surface
Migration of the adsorbed reactants on the surface.
Carbon monoxide and nitrogen monoxide arranged prior to reacting
Reaction of the adsorbed substances.
Carbon dioxide and nitrogen form from previous molecules
Escape, or desorption, of the products.
Carbon dioxide and nitrogen gases escape (desorb) from the platinum surface