Volumetric Method Flashcards
The determination of the volumeof a
solution of known concentration required to
react with a given amount of a substance to
be analyzed.
Volumetric Method
Acid and base combine to form SALT and WATER
NEUTRALIZATION
The 3 principle involved in volumetric method neutralization
Precipitation, Complexation, REDOX
the chemical substance being analyzed or the
active constituentin the sample.
Analyte /titrand
one which concentration is accurately known.- written using 4 decimal places
Standard solution(titrant or Volumetric Solution)
process by which a standard solution is brought
into reaction until the desired reaction is
accomplished
Titration
a chemical which changes color at or very near
the endpoint.
Indicator/ Test solution
Reagents in such
solvents and of such
definite concentrations
that it will suitable for
specified purpose
Test solution (indicator)
Usual concentration is _______,
with _______ of indicator
used for ____ of the analyte.
0.05% (1)
0.1 to 0.2 ml (2)
10 ml (3)
shown by the change of color of the indicator. can be seen by a naked eye
Endpoint / practical
is the theoretical point at which equivalent amounts of each substance have reacted
Equivalence point/ stoichiometric point /theoretical endpoint
(ph range) 0 –2.0
(Acid ) Yellow
(Base) Green
Malachite Green
(ph range) 3.2 -4.4
(Acid ) Pink
(Base) Yellow
Methyl orange
(ph range) 4.2 –6.2
(Acid ) Red
(Base) Yellow
Methyl Red
(ph range) 6.0 –7.6
(Acid ) Yellow
(Base) Blue
Bromothymol blue
(ph range) 8 -10
(Acid ) Colorless
(Base) Pink or red
Phenolphthalein
(ph range) 8 –9.2
(Acid ) yellow
(Base) blue
Thymol blue
_________follow the color of acids
Methyl Red and methyl orange
_________ follow the color of bases
Malachite green, bromothymol blue and thymol blue
When weak acid is titrated with strong alkali,
use ???
phenolphthalein
When weak alkali is titrated with strong acid,
use ???
methyl red
When a strong acidis titrated with a strong alkali, ???
methyl red, methyl orange or Pp may be used
____ should never be titrated with _____ indicator will not give a sharp endpoint
Weak alkali (1)
weak acid (2)
Precipitation indicator
common: silver nitrate (AgNO3)
*Dichlorofluorescein
*Eosin Y
*Potassium chromate
*FAS (Ferrous Ammonium Sulfate)
Complexometry indicator
common: EDTA/ Ethylene diamine tetraacetic acid
* Dithiazone
*Eriochrome black
*Hydroxynaphthol blue
REDOX indicator
*Iodine TS
*Potassium
permanganate VS
*Starch TS
number of moles of reactive unit in a compound
that which reacts or takes the place of one mole of Hydrogen ion
ACIDS/Bases -# of H or OH
Salts –Valence of cation
Equivalent
mass of one equivalent
*weight that is chemically equivalent to the reacting
power of one of one atomic weight of hydrogen
Equivalent weight
Strength in grams equivalent to milliliter of
standard solution or the weight of a substance
chemically equivalent to 1 ml of a standard
solution.
TITER
contains one gram equivalent weight of solute in a liter of
solution or one gram milliequivalent weight in a milliliter of solution.
Normality/ Normal solution
contains a mole (one gram molecular
weight) in a liter of solution or one millimole per
milliliter of solution. A moleis the molecular weight
expressed in grams. A millimoleis one thousandth part of
a mole.
Molarity
a section of chemistry that involves using relationships between reactants and/or products in a chemical reaction to determine desired quantitative data.
Stoichiometry
Knowing EXACTLY
what the concentration
of the solution
Process of determining exact concentration
of a solution.
Standardization
2 Types of Volumetric solutions:
Primary standard
Secondary standard
-chemically pure solid substance almost
99.9% pure used in the standardization of a
solution
Primary Standard
Primary Standard for acid solutions?
Anhydrous pure sodium carbonate Calcium carbonate
THAM
(trihydroxymethylaminomethane)
Primary Standard for alkali solutions
benzoic acid,
potassium biphthalate
sulfamic
Substance that is not necessarily pure
but whose exact purity is known.
*A standard solution is a commonly used
______
Secondary Standard
acid burette is also known as?
provide three-way stopcocks for easier fill
Geissler burette
burettes do not have stopcocks at their tips and use to hold a base titrant
Mohr burette
part of volumetric analysis whereby an acid solution at known concentration, along with a specific indicator, is used to titrate a base solution and thus work out its concentration“.
titrant: acid
analyte: Base
Acidimetry
part of volumetric chemical analysis which enables us to work out the concentration of an acid solution using an alkaline solution at a known concentration and a suitable indicator.
titrant: Base
analyte: Acid
alkalimetry
