Album 2, ingles 1

NOMENCLATURE STOICHIOME, SOLUTIONS AND PROPERTIES COLLIGATIVE

Schoolgirl: Pedroso Maria Angelica School: 49, Chemical Engineering Ingles I

Chemical bond according to Lewis structure

Lewis structures , also called point diagram , model or representation of Lewis Lewis , is a graphical representation showing the electron pairs of bonds between atoms in a molecule and the lone pairs of electrons that may exist. They are adequate and simple representations of ions and compounds , facilitating accurate count of electrons and form an important basis for predicting relative stabilities .

This representation is used to find the number of valence electrons of an element interacting with others or between the same species , forming links either single, double, or triple and these are closely relative to the chemical bonds between the molecules and its molecular geometry, and the distance between each bond formed .

Lewis structures show different atoms of a given molecule by using their chemical symbol and lines drawn between the atoms that are bonded together . Sometimes , to represent each link point pairs are used instead of lines. The desapartados electrons ( those not participating in the links) are represented by a line or a couple of points , and placed around the atoms to which it belongs.

Sort the chemical bonds as ionic, covalent coordinated

A chemical bond corresponds to the force that binds two atoms or bonds , whether they are same or different. The links can be classified into three main groups: ionic, covalent and dative bonds . Links occur as a result of the movement of electrons in atoms , regardless of the type of bond that is formed.

But not just any elecrtr贸n can form a bond, but only electrons of the last ( outer) energy level.

Ionic bond : An ionic bond can be defined as the force that binds two atoms through an electronic transfer. An electronic transfer is when an electropositive element binds with an electronegative element . The greater the electronegativity difference between the elements , the stronger will be the ionic bond. Considerarque begins to two atoms are bonded through an ionic bond when sudiferencia electronegativity is higher than 1.7 . An example of a compound bound through ionic bonding shown in Image 27 , while in the Image 28 is some ways to write compounds linked by this type of link.

Covalent bond : The covalent bond is the force that binds two atoms by the sharing of one electron per atom. Within this type of link we can find two types: the polar covalent bond and non-polar covalent bond . The first sub type corresponds to those compounds in which the electronegativity difference of the atoms that compose it goes from 0 to 1.7 (excluding 0).

Geometry of the molecules

The molecular geometry is three-dimensional arrangement of atoms which form a molecule . It is very important to correctly know the geometry of a molecule , since it is directly related to most chemical and physical properties , such as boiling point, density , solubility , etc. .

If we know the Lewis structure of a molecule , we can predict their geometry using the theory of electron pair repulsion of the valence shell (VSEPR ) . This theory is based on the fact that electrons tend to repel each other ( by similarity of loads ) . Therefore, the orbital containing electrons are oriented so that they are as far apart .

Note that the geometry of the molecule is always referred to the central atom , and to determine it correctly, we must know the total coordination number of the atom

The chemical equation and the stoichiometric calculation

If you have correctly written chemical equation equaled a certain chemical reaction, as each formula represents not only the substance but also a formula ( or molecular ) weight thereof , can establish relationships between the weights of any two reactants and calculate from one of these relationships , the amount of a substance known if the other bodies. In the case of gaseous substances , the molecular formula represents not only the gram molecular weight but also the molar volume, which , in normal conditions , is equal , very approximately 22.4 liters .

From a chemical standpoint correct these calculations should best be performed by determining the number of moles of the substance to be based on the number of moles of a given substance and the conversion factor from one to another product, which is deduced from the relationship between the number of molecules ( and moles ) between both drugs, defined by the relevant chemical equation. Of this number of moles of the substance or weight , if any , being a gas, the volume at the desired conditions is calculated.

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