Chemistry

Electric conduction Some solids are conducting the electricity and some are not. We will explain here from where the conductivity comes and the difference between a conductor and an insulator. The conductivity is explained by the band theory. We have seen in

The state of compounds depends on the temperature and on the pressure. We map the states of the matter on the diagram of phases. The pressure is put as ordinate and the temperature as abscise. The states are separated by

In gases, the heat capacity was a resultant of translation, vibration and rotation. In a solid, there is no translation and no rotation. The atoms may vibe around their equilibrium position. The vibration involves a potential energy and a kinetic

A characteristic of the solids is that they have their own shape. Liquids are taking the shape of their recipient and gases take all the available space. So solids have their own shape but some are malleable, can be cut,

Liquids Liquids are a condensed state: the volume of a liquid does not change by much when a pressure is applied. A liquid is a fluid: it has not its own shape and molecules can move inside it. As said previously, liquids

The states of the matter We can consider 3 different states –gas, liquid and solid– and a melange of them. One important difference between the three states of the matter is the volume they occupy. A gaz takes all the

Oxido-reductions, or redox, are reactions involving a transfer of charge between molecules.  During such reactions, some chemical energy is transformed into electrical energy. An oxidation reaction is a reaction during which a substrate (molecule, atom or ion) loses electrons. A reduction reaction is a reaction

Atoms make liaisons because they get more stability. A proof is that to break a liaison, we need to give energy to the molecule. Atoms in a molecule are at a given distance, and oscillate slightly from this position depending

The table of Mendeleev is also called the periodic table of the elements. More than a simple list of the existing atoms. Mendeleev sorted the elements with regard to their oxidation/reduction by O/H  R20  R0                  

Let’s resume what we know from the atoms: atoms can be broken and are composed of charged species – protons and electrons – and neutral particles – the neutrons. Atoms are different for each element (or isotope) by the number