LET THE TITRATIONS BEGIN

1
LET THE TITRATIONS BEGIN!

• TITRATION TERMINOLOGY
• TITRATION CALCULATIONS
• PRECIPITATION TITRATIONS
• TITRATION OF MIXTURES

2
TERMINOLOGY

• Titrant is added to react with the analyte
  (usually from a buret)
• Equivalence point is when moles of titrant are
  added that equal the moles required to react with
  the analyte
• End point is when the equivalence point is
  observed
• Titration Error End point-Equivalence point
• Indicators are compounds with physical properties
  that are expressed at or near the equivalence
  point

3
TERMINOLOGY

• Blank titration is performed with out any analyte
  to determine what existing solution components
  add to the titration
• Primary Standard is a compound which is stable,
  available in pure form and can be weighed
  directly. It is used to standardize solutions
  used in titrations
• Back titrations are when goes past the
  equivalence point on purpose and then titrates
  the excess titrant itself with another reagent.
  They are usually used when the first
  titrant-analyte equivalence point is difficult to
  detect.

4
(No Transcript)
5
Titration Calculations

• In almost all titration calculations, we
• Write the balanced equation (sometimes net ionic
  equation if this suits you)
• Calculate how much (mass, volume or moles) of
  titrant are needed to reach the equivalence point
• Sometimes continue the calculations if needed.
  This continuation is normally dependent on
  whether we are before, at or after the
  equivalence point.

6
Example.

• Oxalic acid dihydrate is a primary standard. It
  is used to standardize sodium hydroxide. 1.000
  grams of oxalic acid are used to standardize a
  solution of sodium hydroxide. 10.42 mL of NaOH
  are delivered from the buret to reach the end
  point. What is the molarity of the NaOH?

7
Example

• A 20.00 mL solution of sulfuric acid requires
  35.00 mL of 0.75 M KOH to reach the equivalence
  point. How many grams of sulfuric acid are in the
  original solution?

8
Precipitation Titrations

• Precipitation titrations are used in very limited
  instances, but are widely used to explain
  titration theory.
• Usually in a precipitation titration, we are
  determining some analyte that the titrant forms a
  precipitate with.
• For example, one can determine the concentration
  of many anions (especially halides) using silver
  as a titrant.

9
(No Transcript)
10
Titration of Iodide with Silver Ion
11
Steps.

• Write a balanced equation
• Write the Ksp equilibrium expression
• Calculate Veq (volume of equivalence point)
• Determine where in the titration curve you are
  (Before, At, After Veq)
• Solve
• Plot Titration Curve if necessary
• Lets sketch the titration curve for the previous
  example.

12
SOLVE!!!
13
(No Transcript)
14
(No Transcript)
15
(No Transcript)