# PHYSICAL CHEMISTRY

## Learning outcomes of the course unit

The aim of the course is to establish and to develop the principles for the explanation and the interpretation of chemical reactions, by means of models, peculiarity of the Physical Chemistry. The students would acquire knowledge of classical, statistical, and non-equilibrium thermodynamics, of kinetics, of quantum mechanics and spectroscopy, especially with regard to the study and the interpretation of biochemical and biological processes.

## Prerequisites

No preliminary examinations are requested, but it is recommended to attend the courses of General Chemistry, Physics and Mathematics before the course of Physical Chemistry.

## Course contents summary

Equilibrium thermodynamics applied to chemical and biological systems with a statistical thermodynamics outline. Variables and state functions. The laws of thermodynamics. The temperature and pressure dependence of thermodynamic quantities. Thermochemistry. Calorimetry.. Outline of statistical thermodynamics. The molecular interpretation of thermodynamic quantities. Molecular partition function. Maxwell’s equations. Exercises.

Changes of state: physical transformations of pure substances. Phase diagrams. Clausius-Clapeyron equation. Gas-liquid phase transition and critical phenomena. The principle of corresponding states. Gibbs phase rule

Changes of state: physical transformations of simple mixtures. Open systems and partial molar quantities. Ideal and real solutions. Raoult and Henry laws. Fugacity and activity. Water activity in foods. Regular solutions. Ideal mixing and excess functions. Phase equilibria in binary systems. Fractional distillation. Azeotropes, eutectic, partially miscible liquids, binary mixtures compounds forming. Solvent chemical potential. Colligative properties. Molecular weight measurements. Membrane equilibria. Solutions of macromolecules. Dialysis equilibrium. Donnan equilibrium.

Equilibria of chemical reactions. Gibbs free energy and equilibrium constant. Activity and ionic strength. Statistical Thermodynamic interpretation of equilibria in solution. The Bjerrum function. Distribution diagrams. Binding curves. Cooperativity.

Electrochemistry. Electrochemical cells. Electrodes. Nernst equation. Standard reduction potentials. The potentiometer. Electrolyte concentration cells. Nerve stimulus.

Bioenergetics. Active and passive processes. Transport phenomena: passive and active transport. Exergonic and endergonic reactions. Coupled reactions. High energy compounds. Scale of transfer potentials.

Non-equilibrium thermodynamics and transport processes. Force and flow. Phenomenological equations. Curie theorem. Prigogine theorem. Onsager law. Dissipation function. Steady state concept. Mobility of the ions in solution. Electrophoresis. Diffusion. Sedimentation. Viscosity.

Chemical kinetics. The rate of chemical reactions. Stoichiometry, order and , molecularity. 1st and 2nd order reactions. Half-life time. Arrhenius equation. Catalysis. Enzyme kinetics. Fast reactions.

Intermolecular forces. Van de Waals forces. Dipole and induced dipole. Potential energy. Hydrogen bond. Hydrophobic interactions. Partition coefficient.

Colloid, surface chemistry and biopolymers. Definition and classification. Surface tension. Intermolecular forces in colloidal systems. DLVO theory. Structure and classification of surfactants. Micelle formation. Solid-gas, liquid-gas, liquid-liquid, solid-liquid interfaces. Adhesion and cohesion work. Emulsions. Emulsifiers and stabilizers in foods. Microemulsions. Liquid crystals. Langmuir-Blodgett films. Biological and artificial membranes.

Quantumchemistry. The failure of classical mechanics. The quantization of energy. The rhodopsin and the vision mechanism. The wave-particle dualism. Basic assumptions of quantum mechanics. The wave function. The operators. Shrödinger equation. The particle in a box. Harmonic oscillator and diatomic molecules. Rigid rotator. Atoms and molecules.

Spectroscopy. Electromagnetic radiation. Longitudinal and transverse wave. Polarization. Addition of waves. Interaction of light with matter: absorption, emission, scattering. Rayleigh limit, Thomson limit, Lorentz limit. Electromagnetic spectrum. Energy levels and photons. Surrounding effect: colour vision. Time scale and rate of the spectroscopic transitions. Induced dipole moment: classical an quantum mechanics interpretation. Outline of UV-visible, IR, Raman spectroscopy and of circular dichroism and optical rotatory dispersion. LASER.

## Recommended readings

P. W. Atkins, J. De Paula, Chimica Fisica Biologica, vol.1 e 2, Zanichelli, Bologna, 2008

P. W. Atkins, J. De Paula, Chimica Fisica, quarta edizione italiana, Zanichelli, Bologna, 2004.

P. W. Atkins, R.S. Friedman, Meccanica Quantistica Molecolare, Zanichelli, Bologna, 2000

## Teaching methods

Lectures by means of computer presentations, available to the students before classes.

## Assessment methods and criteria

During teaching activity (three months) the students can take three written “in itinere” tests, one each month or, otherwise, there is a written examination on the whole syllabus during scheduled examination sections.