Analytical Chemistry (correct answers)
ANALYTICAL CHEMISTRY correct answers Branch of chemistry that deals with the
separation, identification and composition of matter
Gravimetric Method correct answers Measurement of mass of substance that is
chemically related to the analyte
Volumetric Method correct answers Measures the volume of solution necessary to read
completely with the analyte.
Spectroscopic Method correct answers Measures the electromagnetic radiation
produced by the analyte or its interactions with it.
Electroanalytic Method correct answers Measures the electrical properties of the
analyte such as current, potential, resistance, and amount of charge
Kjeldahl Method correct answers Determination of Organic Nitrogen (Amines, Amides,
Nitriles and Nitro Group: %N or %Protein
Double Indicator Method correct answers To determine the composition of a soda ash
sample. Two indicators (one alkaline range one acidic) Example: Phenolphthalein
endpoint (Na2CO3 and NaOH) and methyl red endpoint (Na2CO3 and NaHCO3)
Argentometric titration correct answers Titration with Silver Nitrate AgNO3
Mohr Method correct answers Direct method for halides and cyanides; Titration is
carried out between pH of 7-10. Usually, a low concentration of chromate is desired to
detect the end point clearly since a chromate ion imparts an intense yellow color.
Volhard Method correct answers For the formation of a colored complexion; Direct
method for silver; Indirect method for halides; Titration is carried out in acidic condition
to hasten precipitation of ferric ion to its hydrated oxide form.
Fajan's Method correct answers For the formation of a colored adsorption complex;
same as Mohr's but uses DCF dichlorofluorescein; between pH 4-7, dextrin is added to
prevent excessive coagulation of the AgCl precipitate.
Liebig Method correct answers Determination of Cyanide, carried by the dropwise
addition of AgNO3 in a solution of a cyanide forming a soluble cyanide complex of silver
Permanganate Process correct answers Oxidation-Reduction Titration with KMnO4;
Self-indicating.
Dichromate Process correct answers Cr2O72-+6e- -> 2Cr3+
, Iodometric Titration correct answers Indirect titration with Iodine.
Dumas Method correct answers Determination of Nitrogen; Faster and automated
compared to Kjeldahl method. Does not use toxic catalysts; does not give true protein, it
measures the nonprotein nitrogen.
Winkler Method correct answers Method to measure dissolved oxygen in fresh water
systems
Wij's Method correct answers A method for determining the iodine number that consists
in adding a solution of iodine monochloride in glacial acetic acid and estimating the
excess of unused halogen by titration with sodium thiosulfate.
Von Weimarn Theory of Relative Supersaturation correct answers It involves a
systematic study of the relationship between particle size of precipitate and rate of
precipitation (the initial rate of precipitation is directly proportional to the relative
supersaturation.
Qualitative Analysis correct answers What is present; type of analysis that reveals the
components of the sample.
Quantitative Analysis correct answers How much is present; Type of analysis that
determines the amount of components present in a sample
Association of Analytical Chemists AOAC correct answers An association of analytical
chemists, chooses a method based on accuracy, reliability, cost, complexity of sample,
and type of solvent used (water, oxidizing, non-oxidizing, etc.)
Analyte correct answers Is any component of a sample whose presence and/or quantity
is to be determined.
Titrimetry correct answers Any of the group of analytical methods that are based upon
determining the quantity of a reagent of known strength that is required to react
completely with the analyte.
Titration correct answers An analytical process in which a standard reagent is added to
a solution of an analyte until the reaction between the analyte and the reagent is judged
to be complete.
Direct Titration correct answers type of titration where the analyte reacts with the
standard solution directly
Back Titration correct answers type of titration where an excess standard solution is
added and the excess is determined by the addition of another standard solution.
ANALYTICAL CHEMISTRY correct answers Branch of chemistry that deals with the
separation, identification and composition of matter
Gravimetric Method correct answers Measurement of mass of substance that is
chemically related to the analyte
Volumetric Method correct answers Measures the volume of solution necessary to read
completely with the analyte.
Spectroscopic Method correct answers Measures the electromagnetic radiation
produced by the analyte or its interactions with it.
Electroanalytic Method correct answers Measures the electrical properties of the
analyte such as current, potential, resistance, and amount of charge
Kjeldahl Method correct answers Determination of Organic Nitrogen (Amines, Amides,
Nitriles and Nitro Group: %N or %Protein
Double Indicator Method correct answers To determine the composition of a soda ash
sample. Two indicators (one alkaline range one acidic) Example: Phenolphthalein
endpoint (Na2CO3 and NaOH) and methyl red endpoint (Na2CO3 and NaHCO3)
Argentometric titration correct answers Titration with Silver Nitrate AgNO3
Mohr Method correct answers Direct method for halides and cyanides; Titration is
carried out between pH of 7-10. Usually, a low concentration of chromate is desired to
detect the end point clearly since a chromate ion imparts an intense yellow color.
Volhard Method correct answers For the formation of a colored complexion; Direct
method for silver; Indirect method for halides; Titration is carried out in acidic condition
to hasten precipitation of ferric ion to its hydrated oxide form.
Fajan's Method correct answers For the formation of a colored adsorption complex;
same as Mohr's but uses DCF dichlorofluorescein; between pH 4-7, dextrin is added to
prevent excessive coagulation of the AgCl precipitate.
Liebig Method correct answers Determination of Cyanide, carried by the dropwise
addition of AgNO3 in a solution of a cyanide forming a soluble cyanide complex of silver
Permanganate Process correct answers Oxidation-Reduction Titration with KMnO4;
Self-indicating.
Dichromate Process correct answers Cr2O72-+6e- -> 2Cr3+
, Iodometric Titration correct answers Indirect titration with Iodine.
Dumas Method correct answers Determination of Nitrogen; Faster and automated
compared to Kjeldahl method. Does not use toxic catalysts; does not give true protein, it
measures the nonprotein nitrogen.
Winkler Method correct answers Method to measure dissolved oxygen in fresh water
systems
Wij's Method correct answers A method for determining the iodine number that consists
in adding a solution of iodine monochloride in glacial acetic acid and estimating the
excess of unused halogen by titration with sodium thiosulfate.
Von Weimarn Theory of Relative Supersaturation correct answers It involves a
systematic study of the relationship between particle size of precipitate and rate of
precipitation (the initial rate of precipitation is directly proportional to the relative
supersaturation.
Qualitative Analysis correct answers What is present; type of analysis that reveals the
components of the sample.
Quantitative Analysis correct answers How much is present; Type of analysis that
determines the amount of components present in a sample
Association of Analytical Chemists AOAC correct answers An association of analytical
chemists, chooses a method based on accuracy, reliability, cost, complexity of sample,
and type of solvent used (water, oxidizing, non-oxidizing, etc.)
Analyte correct answers Is any component of a sample whose presence and/or quantity
is to be determined.
Titrimetry correct answers Any of the group of analytical methods that are based upon
determining the quantity of a reagent of known strength that is required to react
completely with the analyte.
Titration correct answers An analytical process in which a standard reagent is added to
a solution of an analyte until the reaction between the analyte and the reagent is judged
to be complete.
Direct Titration correct answers type of titration where the analyte reacts with the
standard solution directly
Back Titration correct answers type of titration where an excess standard solution is
added and the excess is determined by the addition of another standard solution.
