Using a table in equilibrium calculations

The table format that was used in the preceding problem is very useful in equilibrium calculations. Successful solution of such problems depends on
 
  1. writing the K expression correctly. Remember that solids and pure liquids do not appear in equilibrium constant expressions.
     
  2. paying careful attention to which of the given data refers to initial pressures and which refers to equilibrium pressures.
     
  3. paying careful attention to the sign and magnitude of the changes that you tabulate.
     
    • The ratio of the changes must be the ratio of the coefficients on these substances in the balanced equation
       
    • Substances formed in the reaction occurring to reach equilibrium are assigned positive changes
       
    • Substances consumed in the reaction occurring to reach equilibrium are assigned negative changes.
Dr Sheila Woodgate
© The University of Auckland 2002