Volumetric Analysis
9
Experiment
A Volumetric
Analysis
A titrimetric analysis requires the careful addition of titrant.
• To prepare and standardize a sodium hydroxide solution
• To determine the molar concentration of a strong acid
Objectives
The following techniques are used in the Experimental Procedure
Techniques
2
4
16b
16a
90
80
5
16c
6
13c
15a
15b
!
A chemical analysis that is performed primarily with the aid of volumetric glassware (e.g., pipets, burets, volumetric flasks) is called volumetric analysis. For a volumetric analysis procedure, a known quantity or a carefully measured amount of one substance reacts with a to-be-determined amount of another substance with the reaction occurring in aqueous solution. The volumes of all solutions are carefully measured with volumetric glassware.
The known amount of the substance for an analysis is generally measured and available in two ways:
1. As a primary standard: A precise mass (and thus, moles) of a solid substance is measured on a balance, dissolved in water, and then reacted with the substance being analyzed.
2. As a standard solution: A measured number of moles of substance is present in a measured volume of solution—a solution of known concentration, generally expressed as the molar concentration (or molarity) of the substance. A measured volume of the standard solution then reacts with the substance being analyzed.
Introduction
Primary standard: a substance that has a known high degree of purity, a relatively large molar mass, is nonhygroscopic, and reacts in a predictable way
Standard solution: a solution having a very well known concentration of a solute The reaction of the known substance with the substance to be analyzed, occurring in aqueous solution, is conducted by a titration procedure.
The titration procedure requires a buret to dispense a liquid, called the titrant, into a flask containing the analyte (Figure 9.1a). The titrant
Experiment
A Volumetric
Analysis
A titrimetric analysis requires the careful addition of titrant.
• To prepare and standardize a sodium hydroxide solution
• To determine the molar concentration of a strong acid
Objectives
The following techniques are used in the Experimental Procedure
Techniques
2
4
16b
16a
90
80
5
16c
6
13c
15a
15b
!
A chemical analysis that is performed primarily with the aid of volumetric glassware (e.g., pipets, burets, volumetric flasks) is called volumetric analysis. For a volumetric analysis procedure, a known quantity or a carefully measured amount of one substance reacts with a to-be-determined amount of another substance with the reaction occurring in aqueous solution. The volumes of all solutions are carefully measured with volumetric glassware.
The known amount of the substance for an analysis is generally measured and available in two ways:
1. As a primary standard: A precise mass (and thus, moles) of a solid substance is measured on a balance, dissolved in water, and then reacted with the substance being analyzed.
2. As a standard solution: A measured number of moles of substance is present in a measured volume of solution—a solution of known concentration, generally expressed as the molar concentration (or molarity) of the substance. A measured volume of the standard solution then reacts with the substance being analyzed.
Introduction
Primary standard: a substance that has a known high degree of purity, a relatively large molar mass, is nonhygroscopic, and reacts in a predictable way
Standard solution: a solution having a very well known concentration of a solute The reaction of the known substance with the substance to be analyzed, occurring in aqueous solution, is conducted by a titration procedure.
The titration procedure requires a buret to dispense a liquid, called the titrant, into a flask containing the analyte (Figure 9.1a). The titrant