# ANALYTICAL CHEMISTRY AND LABORATORY OF ANALYTICAL CHEMISTRY

## Learning outcomes of the course unit

The student gains the principles and the analytical procedures for the characterization of chemical compounds, possesses basic knowledge of quantitative chemical analysis, with reference to the analytical aspects of chemical equilibria, and to the methods of volumetric analysis. The student is also able to perform stoichiometric calculations and practical operations in relation to the preparation of solutions with known concentration and is able to choose and use the best method of separation, purification and analysis of chemical mixtures

## Course contents summary

The course is focused on the systematic treatment of homogeneous and heterogeneous equilibria treated in an analytical key and applied to quantitative volumetric analyzes, proposed in the relative laboratory experiences

## Course contents

Main principles of thermodynamics of chemical equilibrium, homogeneous and heterogeneous equilibria, mass and charge balances, effect of the common ion. Distribution functions, calculation of equilibrium concentrations. Examples, calculations.

- Main principles of protonation equilibria, water ionic product, acids and bases, poliprotic acids, buffers, hydrolysis. Distribution diagrams of acids as a function of pH. Examples, calculations.

- Activity of ions in solution: role of ionic strength in ionic equilibria, activity coefficients and their use, effect of the extraneous ion on the solubility.

- Main principles of solubility of ionic compounds, solubility product, effect of the common ion. Fractioned separation by precipitation, solubility of salts as a function of pH. Examples, calculations.

- Main principles of redox equilibria, electrochemical series of standard potentials, Nernst equation, cell potentials. Influence of pH on redox equilibria. Examples, calculations.

- Complexation equilibria, chelate complexes, EDTA, effect of pH on complexing power, distribution diagrams, conditional formation constants, examples, calculations.

- Interactions between solubility, protonation, complexation, and redox equilibria. Dissolution of precipitates by formation of complexes. Examples, applications.

- Principles of quantitative analysis.

• Volumetric analysis. Examples of precipitation titrations; trend of a precipitation titration curve; titration of mixtures; calculation of the final point.

• Acid-base titrations.

• Strong acid - strong base titration; weak acid - strong base titration; titration of polyprotic acids; determination of the end point of the titration; chromatic indicators.

• Complexometric titrations; metal chelate complexes; chelation effect; EDTA;

titration curves with EDTA; metallochromic indicators• Redox titrations. Permanganometry, Iodometry, instrumental monitoring, redox potential trend during titration, redox indicators.

Laboratory Demonstrations:

1. PRECIPITATION TITRATION AND ASSESSMENT OF THE ROBUSTNESS OF THE METHOD AS A FUNCTION OF THE AMOUNT OF INDICATOR

2. DETERMINATION OF THE TOTAL HARDNESS OF WATER WITH EDTA

3. DETERMINATION OF ALKALINITY AND 2 FREE CO2 IN WATER

4. DETERMINATION OF WATER OXIDABILITY ACCORDING TO KUBEL’S METHOD

5. DETERMINATION OF THE DISSOLVED OXYGEN ACCORDING TO WINKLER’S METHOD

6. DETERMINATION OF THE MAIN CONSTITUENTS OF "NORDISKT GULD" COINS (10, 20 AND 50 EUROCENT)

## Recommended readings

D. C. Harris; Chimica analitica quantitativa. Terza edizione italiana condotta sulla nona edizione americana; Ed. ZanichelliP. Michelin Lausarot – G. A. Vaglio; Stechiometria – Guida alla soluzione di problemi di Chimica: Ed. Piccin

## Teaching methods

Frontal classes dealing with demonstrations concerning the systematic treatment of chemical equilibria, including the guided solution of problems relevant to the aforementioned equilibria. Description of the purposes, methods and procedures for the execution of the proposed laboratory practical demonstrations.

## Assessment methods and criteria

The student compiles a laboratory report, in electronic format, showing the results and conclusions of the laboratory experience. After passing the written test, which requires the solution of problems and questions dealing with the chemical equilibria treated in the course, the student is admitted to the oral examination, during which the written test is discussed, the report and the overall knowledge of the arguments are verified.