kinetics

• what must occur for a reaction to take place?

  particles must collide with enough energy to break bonds
• why does everything not react?

  because most collisions are not strong enough to break bonds
• what are the things that speed up rate of reaction?

  increase temp, increase conc, increase gas pressure, increase surface area, use a catalyst
• what does increasing temp do on rate of reaction?

  increases the speed of the molecules which increases both energy and number of collisions
• what does increasing conc do to the rate of reaction?

  more particles, closer the particles are, more collisions
• what does increasing the pressure of gas do to the rate of reaction?

  same as conc, more successful collisions
• what does increasing surface area do to rate of reaction?

  bigger surface area for solid reactants, more space available to collide
• what does adding a catalyst do to the rate of reaction?

  substance that speeds up chemical reaction without being chemically changed itself
• what is activation energy?

  the minimum energy needed to start a reaction
• what is an endothermic reaction?

  a reaction that takes in heat from its surroundings, products have more energy than the reactants
• what are exothermic reactions?

  reactions that release heat energy, reactants have higher energy than products
• what will happen with a reaction with a large Ea at room temp?


  react very slowly, not enough collisions to make it quick
• what will happen to a reaction with a small activation energy at room temp?

  happen quickly, enough collisions quickly for reaction to happen
• what is the maxwell-boltzmann distribution curve?

  a curve showing how many particles have enough energy to react
• what does the maxwell-boltzmann distribution curve show?

  no particles have 0 energy, there is no upper limit of energy, average energy is not the same as most possible energy, most particles have intermediate energy
• what happens to the M-B curve as temp increases?

  peaks gets lower and moves further to the right, this means the same Ea has more particles in
• how do catalysts work?

  they provide a different pathway for a reaction, with a lower activation energy
• what do catalytic converters do?

  take in carbon monoxide and nitrogen monoxide and make nitrogen and CO2, this reduces the number of polluting gases in cars
• how do catalysts react?

  on the surface, gases form weak bonds with metal atoms (absorption) this holds the gases in the right place for them to react, then the products breaks away from the metal atoms freeing up more room on the catalyst for more reactions (decomposition)
• why is the strength of the weak bonds critical?

  they must be strong enough to hold gases for long enough to react but weak enough to release products once the reaction is done
• what does CFCs stand for?

  chlorofluorocarbons
• what is the equation for oxygen and ozone decomposition?

  $O_3\ +$$\ O_{ }\rightarrow\left(chlorine\ atom\ catalyst\right)2O_2$
• what are CFCs and where are they found?

  fairly unreactive compounds found in aerosols and polystyrene foams, they escape into the atmosphere and eventually decompose, and release chlorine atoms which act as a catalyst and destroy the ozone layer