Stoichiometry

							Rates of Rxns
I. Factors affecting the rate of rxn
  1. most increase rate w/ increase in
     temp and pressure
  2. more surface area increases rate
  3. concentrated solutions increase
     rate of rxn
  4. larger molecules decrease rate
5. catalysts – substances that
   decrease the energy required to
   activate a rxn
   -- matchmakers of the rxn, get
   things going with less energy =
   faster
   -- not used up/changed in rxn
   i.e. enzymes
6. Inhibitors – substances that slow
     down reactions
     i.e. food preservatives
II. Energy in Rxns
  A. entropy allows for most rxns to
     proceed in one direction
     -- some rxns can be reversed
  B. All rxns involve energy to break
     and form bonds
     1. most result in no net change in
        energy in the environment (0 J)
2. Endothermic – energy is
         absorbed during the rxn
   a. require addition of energy to
      proceed
3. Exothermic – energy is given off
  during the rxn
   a. spontaneous
4. some processes are
    endothermic at the beginning
    and exothermic at the end
    (digestion)