CHEM: TITRIMETRIC METHODS Flashcards
refers to that group of analytical techniques which
takes advantage of titers or concentrations of
solutions.
TITRIMETRY
• The word “titer” is also used to denote
“equivalence” or that amount of a solution required
to complete a chemical reaction.
TITRIMETRY
• often refers to the use of some volume of a solution
of known concentration to determine the quantity
of an analyte
TITRIMETRY
TYPES OF TITRIMETRY
• establishes a quantity of analyte using volumes of
reagents of known concentrations and the
knowledge of the stoichiometry of the reactions
between the reagents and the analytes.
• VOLUME
VOLUMETRIC TITRIMETRY
TYPES OF TITRIMETRY
• determines the quantity of analyte by a measure of
the mass of a solution of known concentration.
• MASS
GRAVIMETRIC TITRIMETRY
TYPES OF TITRIMETRY
• arrives at the amount of analyte by measuring the
number of coulombs or total charge required to
complete a reaction with the
• CUOLOMBS
CUOLOMETRIC TITRIMETRY
is the point where sufficient titrant has been added
to be stoichiometrically equivalent to the amount of
analyte.
- Titrant is the substance being added to the
amount of sample in the Erlenmeyer flask
- The titrant is being place in the burette
- When we say “stoichiometry”, we are referring
to the balanced equation (make sure your
equation is balanced; know how to make your
products)
EQUIVALENCE POINT
• is the point at which some detection technique tells
you that chemical equivalence has been reached.
• Ideally the end point and the equivalence point
should coincide.
• But this rarely happens due to the methods used to
detect the end point.
END POINT
The difference between the end point and the
equivalence point
titration error
is a high purity compound that
serves as a reference material in all volumetric and
mass titrimetric methods
• Ideally the titrant solution would be made from a
primary standard!
• Titrant solutions must be of known concentration!
PRIMARY STANDARD
• High purity
• Stability in presence of air
• Absence of any water of hydration which might vary
with changing humidity and temperature.
• Dissolves readily to produce stable solutions in
solvent of choice
• A relatively large molar mass to minimize weighing
errors
• Reacts rapidly and stoichiometrically with analyte
PRIMARY STANDARD REQUIREMENTS
• Few materials meet all of the primary standard
requirements
• Instead a secondary standard that is standardized
with a primary standard!
- If the primary standard is not available, you can
use the secondary standard.
SECONDARY STANDARDS
• a process in which the concentration of a secondary
standard is determined to a high level of accuracy
by titration with a primary standard.
STANDARDIZATION
EXAMPLES OF PRIMARY STANDARDS
• Primary standards for standardization of NaOH
[base]
- Potassium acid phthalate (KHP) [acid]
• Primary standards for standardization of HCl [acid]
- Sodium carbonate [base]
• Acid-base titration
• Molarity
• The number of moles of species (x) dissolved in 1 L
of solution
• mol/L = M
MOLAR CONCENTRATION
