Reversible Reactions

Reversible Reactions

1. Reversible reactions can reach dynamic equilibrium

   • As the reactants get used up, the forward reaction slows down, as more product is formed, the reverse reaction speeds up
     • After a while, the forward reaction will be going at the same rate as the backward reaction.

2. Le Chatelier's Principle

   • If you change the concentration, pressure or temperature of a reversible reaction, you're going to alter the position of equilibrium. The equilibrium will oppose.
   • Catalysts have no effect on the position of equilibrium but it does reach equilibrium quicker
   • Examples
     • Concentration
     • Temperature
     • Pressure

3. Ethanol Production

   • Ethene and steam
   • Pressure:60-70 atmospheres
     • Higher pressures increase rate or reaction
       • Expensive to produce, need stronger equipment to withstand the pressure
       • Higher pressure produces side reaction
   • Temperature:300 degrees
     • Lower temperatures means high yield
       • But the rate of reaction is slow
   • Carbon neutral

4. Methanol Production

   • Pressure:50-100 atmospheres
   • Temperature: 250 degrees
   • Catalyst: zinc oxide, copper, aluminium oxide
   • Used as car fuels
   • Carbon neutral