A chemical formula allows us to represent the elements that make up a chemical compound .
The proposed means to execute something or resolve an issue is called a formula . For science , a formula is a short form that expresses information in a symbolic way . It is, in this sense, a fixed way of transmitting certain information.
Chemistry , for its part, is the science dedicated to the study of the composition, structure and properties of matter . The changes experienced by it during certain reactions are also part of its concern.
What is a chemical formula
The representation of those elements that form a compound is known as a chemical formula . The formula reflects the proportion in which these elements are found in the compound or the number of atoms that make up a molecule . Some formulas even provide information about how atoms are joined together through chemical bonds and how they are distributed in space.
To name a chemical formula, you must follow the nomenclature rules called chemical formulation . A formula exhibits symbols and subscripts : the chemical formulation states that the symbols indicate the elements present in the compound and the subscripts indicate the number of atoms present in the compound of each element.
H2O is the chemical formula of water.
Classification according to type
It is possible to distinguish between different types of chemical formulas, some of which are set out below:
Empirical formula
This is the expression that shows the proportion in which the atoms are found in a given chemical compound, in the simplest possible way, which is why it is usually called the minimum formula (represented as fm ). It is worth mentioning that it sometimes coincides with the molecular formula (defined below).
A clear example of an empirical formula can be seen in the water molecule, which is represented as H2O, since for every two hydrogen atoms it contains one oxygen atom (this is one of the cases in which the empirical formula coincides with the molecular). With ethane, on the other hand, both formulas are different: the empirical one is CH3; while the molecular one, C2H6.
molecular formula
The molecular formula is used to indicate what type of atoms are found in a given molecular compound, as well as the number of each class of atoms, and its use is only correct in the case of covalent compounds (the union of two non- metals , or well of a non-metal with a metal and when they have an electronegativity difference of less than 1.7). Returning to the case of ethane, its molecular formula states that it has two carbon atoms and six hydrogen atoms, while the empirical formula indicates that for every three hydrogen atoms there is one carbon atom.
Semi-developed formula
It is a formula similar to the molecular one, but it indicates the bonds that exist between each group of atoms in the molecule, to especially highlight the functional ones. It is mainly used in organic chemistry, where it is easy to observe the structure of the carbon chain and each substituent.
Formula developed
It has greater complexity than the previous one, since it shows all the links and represents them in a Cartesian plane, which makes it easier to observe some very important details of its structure.
Structural formula
What differentiates the structural formula from those exposed so far is that it indicates the spatial geometry of the molecule through distances, angles or the use of perspectives in 2 or 3-dimensional diagrams.
Lewis formula
Also called a Lewis diagram or structure, it shows the total number of atoms in a molecule, along with their respective valence electrons, which are represented by dots or lines. It is worth mentioning that its use is not recommended for highly complex structures.