pH and Buffers

• What is a Bronsted-Lowry acid?

  A proton donor
• What is a Bronsted-Lowry base?

  A proton acceptor
• What does neutralisation of an acid and a base produce?

  A conjugate acid and a conjugate base
• General word formula for acid and base neutralisation


  HA(aq) + B(aq) > BH+(aq) + A-(aq)
• How to calculate pH


  -log[H+]=pH
• Write the general Ka expression

  [H+][A-]/[HA]
• How to calculate pKa


  pKa = -log Ka
• equation for Kw in pure water

  [H+][OH]
• How to calculate [H+]

  [H+]= 10^-pH
• What is a buffer?

  A solution that can resist pH change
• What is in a buffer solution?

  A weak acid and its conjugate base
• What does monoprotic mean?

  Releases one mole of H+ per mole in solution
• Describe how buffers work

  -Reduce large change

  -Adding acid/bare would shift the equilibrium

  -Acid/base reacts with OH-/H+ to form water
• Describe the dissociation of a diprotic acid

  1st dissociation = full

  2nd dissociation = partial
• Strong acid-strong base pH curve


  Equivalence point = 7
• Strong acid-weak base pH curve 


  pH of 1-2 to 8-10
• Weak acid-strong base pH curve 


  pH of 4-6 to 12-14
• Weak acid-weak base pH curve 


  No equivalence point
• How is an indicator suitable for a titration based on the titration curve?

  Its end point covers halfway up the equivalence point
• How can Ph be measured continuously?

  With a pH probe AND a data logger