Meaning of Chemical Change
A change implies an alteration, modification or transformation. Chemical, for its part, is that linked to the properties and structure of a substance according to its composition.
It is called chemical change to the process that leads to one or more substances (called reagents) to change its structure and links the molecules, making other substances are called products. These changes can be represented symbolically by chemical equations.
The conditions that surround the chemical change, also known as chemical reaction or chemical phenomenon, affect the obtaining of the products. However, there are values that remain constant, such as the total mass and the electrical charge.
According to DigoPaul, chemical changes are measurable and observable events that cause a change in the chemical composition of substances. The matter becomes and mutates that usually is irreversible.
A chemical change can occur for multiple reasons. There may be proton or electron transfer or heat shedding or absorption, for example.
The reactions redox, also referred to as reactions redox, are among the most common chemical changes. In this case, there is a transfer of electrons between the reactants that generates a modification of their oxidation states.
The reducing agent contributes the electrons to the medium and increases its oxidation state (it oxidizes), while the oxidizing agent receives these electrons, reducing its oxidation state (it reduces). The whole process causes a chemical change in the substances involved.
Broadly speaking, we can say that there are two types of chemical changes: inorganic and organic. With regard to organic chemistry, there are two models in which changes are divided, depending on how they affect oxidation states: redox reactions do affect them, while neutralization reactions do not.
Another possible classification for state changes takes into account the type of structure, and the following arise from there:
* Synthesis: it is also called combination since it combines the reactants with each other to give rise to the origin of a new product;
* simple decomposition: when the splitting of a substance into its components occurs;
* decomposition by means of a reagent: for the decomposition of a substance to take place, the use of a reagent is necessary;
* Substitution: some component of the reagents is replaced by a substance, so that the first one is released. This type of chemical change is also called a displacement;
* double substitution: also called double displacement, and takes place when the elements or groups of elements that participate in the chemical change are exchanged.
According to the type of energy that is exchanged:
* In the form of heat: exothermic reactions enter this group, when the reaction system gives off heat, and endothermic reactions, heat is necessary for the chemical change to take place;
* in the form of light: endoluminous reactions require light from the outside while exoluminous ones emit it;
* in the form of electricity: endoelectric reactions require the contribution of electricity, but exoelectric ones produce it.
Finally, there is the classification according to the class of particles that are exchanged, which can be protons (in acid-base reactions) or electrons (in oxidation-reduction).
In organic chemistry we have chemical changes involving compounds such as alcohols, ketones, aldehydes, alkanes and alkynes, among others, which are found in the functional group that have their classification, their chemical properties and their reactivity. A functional group is one or more atoms that are attached to a carbon chain.