Analytical Chemistry

The Effect of Electrolyte on Chemical Equilibria – Experimentally, we find that the position of most solution equilibria depends on the electrolyte concentration of the medium, even when the added electrolyte contains no ion in common with those participating in the equilibrium. – For example, consider again the oxidation of …

What is Analytical Chemistry? Analytical chemistry is what analytical chemists do. – Analytical chemistry is too broad and active a discipline for us to easily or completely define in an introductory textbook. Instead, we will try to say a little about what analytical chemistry is, as well as a little …

– In this subject, we will discuss the Acid and Base Dissociation Constants (Ka and Kb) Acid and Base Dissociation Constants – When a weak acid or a weak base is dissolved in water, partial dissociation occurs. – Thus, for nitrous acid, we can write: – where Ka is the …

– In this subject, we will discuss the Bronsted-Lowry Acid Strength: Ka and pKa Bronsted-Lowry Acid Strength: Ka and pKa – Many organic reactions involve the transfer of a proton by an acid–base reaction. – An important consideration, therefore, is the relative strengths of compounds that could potentially act as …

– In this subject, we will discuss the Solubility Product (Ksp): Definition, Formula, Problems Solubility Product Constant Ksp – Most, but not all, sparingly soluble salts are essentially completely dissociated in a saturated aqueous solution. – For example, when an excess of barium iodate is equilibrated with water, the dissociation …

– In this subject, we will discuss the Dilution of Solutions and Dilution Law. Dilution of Solutions – Concentrated solutions are often stored in the laboratory stockroom for use as needed. – Frequently we dilute these “stock” solutions before working with them.  – Dilution of solution is the procedure for …

– In this subject, we will discuss the Molarity: definition, formula, solved Problems  – To study solution stoichiometry, we must know how much of the reactants are present in a solution and also how to control the amounts of reactants used to bring about a reaction in aqueous solution. The …

– In this subject, we will discuss Types of Equilibrium Constants used in Analytical Chemistry. Chemical Equilibrium and Equilibrium constants – Many reactions used in analytical chemistry never result in the complete conversion of reactants to products. – Instead, they proceed to a state of chemical equilibrium in which the …

– In this subject, we will discuss the Chemical Composition of Aqueous Solution – Water is the most plentiful solvent on Earth, is easily purified, and is not toxic. – It is, therefore, widely used as a medium for chemical analyses. Classifying Solutions of Electrolytes  – Most of the solutes …

In this subject, we will discuss the Chemical Stoichiometry: Definition, Formula, Example Chemical Stoichiometry – Stoichiometry is the quantitative relationship among the amounts of reacting chemical species. – This subject provides a brief review of stoichiometry and its applications to chemical calculations. – The stoichiometry of a reaction is the …

– In this subject, we will discuss the Concentration of Solutions Concentration of Solutions (Definitions, Formulas, Solved Problems). Concentration of Solutions – For history, measurements and their corresponding units were invented at the local level. – By necessity of primitive communication and local technology, standards were nearly nonexistent, and conversions …

  SI Units   – Scientists throughout the world have adopted a standardized system of units known as the International System of Units (SI). – This system (SI) is based on the seven fundamental base units shown in Table (1). – Numerous other useful units, such as volts, hertz, coulombs, …

– In this subject, we will discuss the Safety in the laboratory Safety in The Laboratory – There is necessarily a degree of risk associated with any work in a chemical laboratory. – Accidents can and do happen. – Strict adherence to the following rules will go far toward preventing …

The Laboratory Notebook – A laboratory notebook is needed to record measurements and observations concerning an analysis. – The book should be permanently bound with consecutively numbered pages (if necessary, the pages should be hand-numbered before any entries are made). – Most notebooks have more than ample room, so there …

– In this subject, we will discuss How to Calibrate Volumetric Glassware in the laboratory Calibration of Volumetric Glassware – Volumetric glassware is calibrated by measuring the mass of a liquid (usually distilled or deionized water) of known density and temperature that is contained in (or delivered by) the volumetric …

  Volumetric Flask – A volumetric flask is manufactured with capacities ranging from 5 mL to 5 L and is usually calibrated to contain (TC) a specified volume when filled to a line etched on the neck.  – They are used for the preparation of standard solutions and the dilution …

Pipets – Pipets permit the transfer of accurately known volumes from one container to another. – Common types are shown in Figure (1), and information concerning their use is given in Table (1).  – A volumetric, or transfer, pipet (Figure 1a) delivers a single, fixed volume between 0.5 and 200 …

Burets – Burets, like measuring pipets, make it possible to deliver any volume up to the maximum capacity of the device. – The precision attainable with a buret is substantially greater than the precision with a pipet. – A buret consists of a calibrated tube to hold the titrant plus …

– The precise measurement of volume is as important to many analytical methods as the precise measurement of mass. (1) Units of Volume – The unit of volume is the liter (L), defined as one cubic decimeter. – The milliliter (mL) is one one-thousandth of a liter (0.001 L) and …

– In this subject, we will discuss the Filtration and Ignition of Solids. – Several techniques and experimental arrangements allow solids to be filtered and ignited with minimal contamination and error. (1) Apparatus for Filtration of Solids (a) Simple Crucibles  – Simple crucibles serve only as containers. – Porcelain, aluminum …