Gravimetric titrimetry

Gravimetric titrimetry — A - titration method in which the mass of - titrant that is added to the - titrand is weighted by using a balance [i]. 

Titrimetry — A chemical analysis based on determining the quantity of - titrant that is required to react completely with the - analyte and that is performed by - titration. There are three common types of titrimetry -> volumetric titrimetry, -r gravimetric titrimetry, and -> coulometric titrimetry [i]. 

Two other types of analytical methods are based on mass. In gravimetric titrimetry, which is described in Section 13D, the mass of a reagent, of known concentration, required to react completely with the analyte provides the information needed to determine the analyte concentration. Atomic mass spectrometry uses a ma.ss. spectrometer to separate the gaseous ions formed from the elements making up a sample of matter. The concentration of the resulting ions is then determined by measuring the electrical current produced when they fall on the suiface of an ion detector. This technique is described briefly in Chapter 28. 

Gravimetric factor, GF The. stoichiometric ratio between the analyte and the solid weighed in a gravimetric analysis. Gravimetric titrimetry Titrations in which the mass of standard titrant is measured rather than volume the concentration of titrant is expressed in mmol/g of solution (rather than the more familiar mmol/mL). 

Many precipitation reactions that are useful as separation techniques for gravimetric analysis fail to meet one or both of two requirements for titrimetry ... 

The quantitative execution of chemical reactions is the basis of the traditional or classical methods of chemical analysis gravimetry, titrimetry and volumetry. In gravimetric analysis the substance being determined is converted into an insoluble precipitate which is collected and weighed, or in the special case of electrogravimetry electrolysis is carried out and the material deposited on one of the electrodes is weighed. 

A matter of practical importance in nonaqueous titrimetry is that, when volumetric equipment is used, errors should be prevented that arise from solvent volatility and from characteristics of viscosity and surface tension that differ from those of water. Temperature coefficients of expansion are often about six times that of water, so careful control of temperature is needed when volumes are being measured. Gravimetric titration techniques are recommended, since they avoid most of these volumetric problems. Details of a gravimetric technique using a syringe have been given. ... 

Precipitation reactions have several applications in analysis in gravimetric methods, in precipitation titrations, and in separations. Gravimetry, which used to be a major l>art of analytical chemistry, has expanded less rapidly than other aspects of analysis and does not now occupy a prominent place. Precipitation titrimetry always has been restricted in application because most precipitation reactions fail to meet the requirements of rapid reaction rate and adequate stoichiometry. In separations, precipitation reactions are used in two ways in one the precipitate involved is of direct concern, and in the other it acts as a carrier for another substance of interest. The application of precipitation reactions to separations is described in Chapter 22. 

Two methods have been developed that are based on measuring the quantity of charge controlled-potential (potentiostatic) coulometry and controlled-cur-rent coulometry, often called coulometric titrimetry. Potentiostatic methods are performed in much the same way as controlled-potential gravimetric methods, with... 

Weight titrimetry Synonymous with gravimetric titriinetiy. Weight/volume percent (w/v) The ratio of the mass of a solute to the volume of solution in which it is dissolved, multiplied by 100%. 

PART III Classical Methods of Analysis 311 Chapter 12 Gravimetric Methods of Analysis 314 Chapter 13 Titrimetric Methods Precipitation Titrimetry 337 Chapter 14 Principles of Neutralization Titrations 368 Chapter 15 Titration Curves for Complex Acid/Base Systems 395 Chapter 16 Applications of Neutralization Titrations 428 Chapter 17 Complexation Reactions and Titrations 449... 

Analytical chemistry began in the late eighteenth century with the work of French chemist Antoine-Laurent Lavoisier and others the discipline was further developed in the nineteenth century by Carl Fresenius and Karl Friedrich Mohr. As a pharmacist s apprentice in Frankfurt, Germany, Fresenius developed an extensive qualitative analysis scheme that, when it was later published, served as the first textbook of analytical chemistry. He built a laboratory at his house that opened in 1848. Here he trained students in gravimetric techniques that he had developed. Mohr developed laboratory devices such as the pinch clamp burette and the volumetric pipette. He also devised a colorimetric endpoint for silver titrations. It was his 1855 book on titrimetry, Lehrhuch der Chemisch-Analytischen Titromethode, that generated widespread interest in the technique. 

The estimation of individual components by gravimetric techniques, IR spectroscopy, UV-visible spectroscopy, HPLC or titrimetry will be described. 

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