Determine the buffer concentration How would you prepare a benzoic acidbenzoate

# Determine the buffer concentration how would you

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3.Determine the buffer concentration Preparing a Buffer SOLUTION:  7.0 13.0 pH 100.0 Equivalence point 1. 1. Stoichiometry Stoichiometry Reaction assumed to run to completion Reaction assumed to run to completion 2. 2. Equilibrium Equilibrium Use weak acid equilibrium to find pH Use weak acid equilibrium to find pH Weak Acid-Strong Base Titration Vol NaOH added (mL) 25 50 3.0 9.0 12.0 Equivalence point pH Differences Vol NaOH Strong acid pH Weak acid Differences and K a Vol 0.10  M  NaOH added (mL) 10 20 30 40 50 60 2.0 4.0 6.0 8.0 10.0 12.0 0 K a   = 10 2 K a   = 10 4 K a   = 10 6 K a   = 10 8 K a   = 10 10 Strong acid pH Titration Calculations 1. 1. Solution of HA Solution of HA 2. 2. Solution of HA and added base Solution of HA and added base 3. 3. Equivalent amounts of HA and added base Equivalent amounts of HA and added base 4. 4. Excess base Excess base A chemist titrates 20.00 mL of 0.2000 M HBrO A chemist titrates 20.00 mL of 0.2000 M HBrO (K (K a = 2.3 x 10 = 2.3 x 10 -9 -9 ) with 0.1000 M NaOH. Find the pH: ) with 0.1000 M NaOH. Find the pH: (a) (a) before any base is added before any base is added (b) (b) when 30.00 mL of NaOH is added when 30.00 mL of NaOH is added (c) (c) at the equivalence point at the equivalence point (d) (d) when the moles of OH when the moles of OH - added are twice the moles of added are twice the moles of HBrO originally present? HBrO originally present? Vol 1.0  M  HCl added 7.0 14.0 50.0 mL Equivalence point pH Titration of Strong Base with Strong Acid Weak Base-Strong Acid Titration 0 Vol 0.10  M  HCl (mL) 10 2 20 30 40 50 60 70 4 6 8 10 12 Equivalence point pH Acid-Base Indicator Indicates endpoint of a titration Indicates endpoint of a titration Endpoint is not necessarily the equivalence point Endpoint is not necessarily the equivalence point O C O C O O (Pink base form, In ) HO C OH C O O (Colorless acid form, HIn) OH 15_334 0 1 2 3 4 5 6 7 8 9 10 11 12 13 The pH ranges shown are approximate.  Specific transition ranges depend on the indicator solvent chosen.  #### You've reached the end of your free preview.

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