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Lecture

Burette and Titrage

In course

CH-108(a): Chemistry Laboratory Work I

Familiariser l'étudiant avec le travail au laboratoire. Travailler de façon quantitative et/ou qualitative. TP réalisés en relation avec les cours de chimie de 1ere année et complémentaires avec le contenu des enseignements TP2 dispensés au semestre suiva ...

Description

This lecture covers the process of titrating an unknown concentration sample of ascorbic acids using an ionometric titration method, including rinsing the burette, filling it with iodine solution, preparing the sample, adding an indicator, and calculating the exact concentration of ascorbic acids in the sample.

Instructors (2)

Anne-Sophie Chauvin

Web of Science Researcher ID F-4905-2011 Google Scholar page: https://scholar.google.ch/citations?user=O_HhJUEAAAAJ&hl=fr&oi=ao ORCID number is 0000-0001-9222-3866 Anne-Sophie Chauvin studied chemistry and biology at the university Paris V-René Descartes in France where she did a PhD in organic chemistry, working on mimetic complexes of the active site of Nitrile Hydratase, under the supervision of Prof. Jean-Claude Chottard. On 1999 she moved for 20 months to the University of Geneva, for a post-doctoral stay under the supervision of Prof. Alexandre Alexakis, where she focused on the determination of the absolute configuration of chiral alcohols using Organophosphorous Diamine Derivatizing Agents by 31P and 1H NMR Spectroscopy. On 2000 she joined the group of Prof Jean-Claude G. Bünzli and was appointed part-time lecturer in 2001, assuming teaching and research responsibilities. On 2006, she obtained the habilitation to direct research from the University René Descartes (HDR, Paris V, France) and since october 2007 she is Maître d'Enseignement et de Recherche at the EPFL. In 2010, she joigned the Laboratory for Photonics and Interfaces (LPI), headed by Pr. Michaël Graëtzel. Since the end of 2014, with the arrival of Dr Marinella Mazzanti at EPFL, she is back to lanthanide chemistry, dealing with coordination polymers. Her research interests concern supramolecular chemistry with the design of ligands which form water soluble complexes with luminescent lanthanides in view of biological applications. She is also interested in the synthesis of ligands and polymers for the extraction of lanthanide ions with high selectivity, and in the development of invisibke inks. She also developed organic dyes for dyes sensitized solar cells DSSC. She is now focusing on coordination polymers with luminescent properties and catalytic activity. Anne-Sophie Chauvin is involved in the teaching of General and Analytical Chemistry for students enrolled on first year in Pharmacy and Biology (UNIL): ex-cathedra courses (Chimie Générale et analytique I et II, approfondissement en chimie analytique pour pharmaciens) and exercices. She is in charge of practical sessions for students enroled in chemistry, forensic sciences, pharmacy and biology. She is elected at the FSB Faculty Council and was member of the EPFL Assembly (AE) for 6 years, until 2018. She was member of the Management committee of the Cost CM 1006 action entitled Eufen: European F-Element Network. She is Member of the Swiss Chemical Society (SCS) and Fellow of the Royal Society of Chemistry (FRSC).

Julien Alexandre Andres

Official source

Related concepts (16)

Iodine value

In chemistry, the iodine value (IV; also iodine absorption value, iodine number or iodine index) is the mass of iodine in grams that is consumed by 100 grams of a chemical substance. Iodine numbers are often used to determine the degree of unsaturation in fats, oils and waxes. In fatty acids, unsaturation occurs mainly as double bonds which are very reactive towards halogens, the iodine in this case. Thus, the higher the iodine value, the more unsaturations are present in the fat.

Iodine

Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a violet gas at . The element was discovered by the French chemist Bernard Courtois in 1811 and was named two years later by Joseph Louis Gay-Lussac, after the Ancient Greek Ιώδης 'violet-coloured'. Iodine occurs in many oxidation states, including iodide (I−), iodate (IO3-), and the various periodate anions.

Titration

Titration (also known as titrimetry and volumetric analysis) is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte (a substance to be analyzed). A reagent, termed the titrant or titrator, is prepared as a standard solution of known concentration and volume. The titrant reacts with a solution of analyte (which may also be termed the titrand) to determine the analyte's concentration. The volume of titrant that reacted with the analyte is termed the titration volume.

Iodine–starch test

The iodine–starch test is a chemical reaction that is used to test for the presence of starch or for iodine. The combination of starch and iodine is intensely blue-black. The interaction between starch and the triiodide anion (I3-) is the basis for iodometry. The iodine–starch test was first described by J. J. Colin and H. F. Gaultier de Claubry, and independently by F. Stromeyer, in 1814. The triiodide anion instantly produces an intense blue-black colour upon contact with starch.

Iodine deficiency

Iodine deficiency is a lack of the trace element iodine, an essential nutrient in the diet. It may result in metabolic problems such as goiter, sometimes as an endemic goiter as well as congenital iodine deficiency syndrome due to untreated congenital hypothyroidism, which results in developmental delays and other health problems. Iodine deficiency is an important global health issue, especially for fertile and pregnant women. It is also a preventable cause of intellectual disability.

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