In the chemical field, the name of " substance " is assigned to any matter or material whose chemical characteristics and internal composition are constant, that is, its compounds which give the chemical properties to the matter such as melting points, boiling points, saturability., among others, never vary, remain in time. These substances are assigned the name of pure to achieve the differentiation with the term mixtures (mixtures is the union of two or more elements and this can be classified as heterogeneous and homogeneous).
What is a substance
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As explained in the previous section, it is a matter or compound whose main characteristic is to remain stable and homogeneous. Chemical substances can also be mentioned here because the main concept has a lot to do with them. Well, chemistry has characteristics and intensive densities in each of the points that make it up regardless of the state in which they are, whether solid, liquid or gaseous. In this same definition are pure substances, which have the characteristic of not decomposing in the face of various physical procedures or processes, for example, water.
Chemicals are made up of atoms, form units, and molecules. These can be presented in 3 forms: liquid, solid and gaseous and each one can be differentiated according to its temperature and pressure. But they also have as fundamental characteristics, physical properties, these are density, boiling point, melting point and solubility, of course, in their different solvents. Each of them can be set, specified and reproduced as long as they are at a certain pressure and temperature.
Substances run the risk of undergoing 3 specific changes, these are chemical, physicochemical and physical. In the first change, it has a complete transformation, as it ceases to be part of the pure ones and becomes a totally different one.
In physicochemical changes, transformation is only suffered by adding another element to the original, for example when a metallic substance is melting and an ingredient is added to pure water. Finally, there are the physical changes, which undergo transformations in form. Each of these changes are totally different and do not interfere with each other.
From the broad point of view, this word can be used in various contexts, they can be religious, political or gastronomic, for example: "The substance and importance of the egg is found directly in the yolk."
"> Loading…Properties of a substance
These have a series of characteristics that are useful when identifying them. These properties have a classification: according to their nature and according to their scope.
Properties according to their nature
Physical
They are those that can be measured, without said action affecting the composition of the substance. A clear example of this property is the boiling point, the density, etc.
It should be added that the physical properties in turn have a series of characteristics, these are: color, odor, temperature and its determination, as said previously, does not affect the composition of the substance at all.
Chemical
Chemical properties can be observed at the same time that it undergoes changes in its composition, that is, when it is transformed into another new substance, they are identified by having changes in its composition due to its measurement. It is important to clarify that these changes can be reversible and irreversible.
Properties according to your scope
General
Also called extensive properties. They are those that do depend on the amounts of material substance that are going to be used, these can be mass or volume.
These properties are called general, because their use does not allow them to be differentiated from one another, as they are present in practically all substances that exist today.
Specific
Also called intensive properties. They are properties that do not merit or do not depend on the amounts of substances considered, that is, they do not depend on the size of a body and not on mass, for example density and melting temperatures.
Differences between substance and mixture
To know the difference between a mixture and a substance, it is imperative to know both definitions. A mixture is a material formed by the combination of two and even more pure components, that is, they are not chemically united. In mixtures there are no chemical reactions, the components do not change their identity, nor their properties. Although mixtures do not have chemical reactions, that does not mean that they cannot react if they are subjected to specific environmental conditions. In addition, mixtures have the ability to separate their components through thermal or physical processes.
Well, pure substances have unalterable components, that is, homogeneous, totally stable. Its physical state is also related to what a pure substance is and that is because it can be solid, liquid or gaseous and still not suffer alterations.
Among the broad examples of pure substances is water. With all this clear, you can talk directly about the differences between a mixture and a substance. Pure ones have uniform compositions, mixtures are unions of different compounds or molecules without chemical reactions. Mixtures have no properties, substances do.
Substance types
These also have a classification according to their types, they are not toxic substances, addictive substances, acids or a gray substance, on the contrary, they are pure substances that have a classification of two aspects and both will be explained in this In the same section, however, it is important to mention what are the details of the pure substances that must be taken into account before explaining their types.
Pure ones do not decompose by physical procedures, but they can have slight or sudden changes due to chemical combinations, that is, they have chemical reactions that alter their original composition. Once this is explained, we can go on to talk about pure simple substances and pure compounds.
Simple substances
They are those whose atoms that compose it are made up of the same element. The number of atoms it has is important because its atomic composition varies according to them, however, the type of atoms does not matter. A clear example of this is diatomic oxygen.
Compound substances
These in addition to being made up of two or more atoms, these can be of different origin, marking a notable difference between simple substances. Among its characteristics is that they contain a chemical formula and there is no way that there is human intervention in them.
Each element of the periodic table can come together without any problem to form a compound substance and once this happens, there is no physical process that can divide or separate it, only a chemical process can do it. Salt and water are two of the best examples that can be had in this area.
But in addition to this, compound substances have one more classification, it is about organic compounds and inorganic compounds. In the first classification are the aliphatic compounds, which have a composition of hydrogen and carbon, the heterocyclic compounds that are composed of elements other than carbon.
Aromatic compounds, organometallic compounds, whose carbon atoms have the ability to create covalent bonds and, lastly, polymers, whose macromolecules are created by the combination of small molecules. The inorganic side is composed of acidic oxides, which are not metallic, basic oxides formed by oxygen and a metal.
"> Loading…Hydrides, which may or may not be metals and are composed of hydrogen and any element. Hydracids are non-metallic hydrides that, when in contact with water, turn into powerful acids. Hydroxides are created by the combination or reaction of basic oxide and water.
There are also oxacids, which have their genesis thanks to the reaction between water and acid oxide. The binary salts are the main result of the mixture or combination of the hydracid with the hydroxide. Finally, the oxysalts, which are formed thanks to hydroxide and an oxacid.
It is also possible to classify chemical substances according to the presence of carbon, this is because it is one of the most abundant elements on earth. The classification itself is also called organic and inorganic.
The organic ones have an atomic composition of carbon, they have the ability to decompose and, as mentioned previously, they can be found all over the world, this means that they can be found both in a living being and in another that does not have life. If their atoms change, these substances can become inorganic, caffeine is an effective example to explain this.
The inorganic ones do not have carbon within their atomic composition or simply, that element is not dispensable or it is not its main component. Any substance lacking in vigor or that does not have the ability to decompose can be entered as an example of this classification, among them, water or metals. Now, some of the inorganic substances can become organic through chemical or physical interventions regardless of the amount of substance that is taken.
Examples of substances
It is important to know each chemical example of the substances to have a broad concept of this topic, it can even be in examples of white or toxic substances. In fact, it is important to clarify what a toxic substance is, since it is nothing more than a chemical substance whose composition is destined to cause damage to living beings from the moment it comes into contact with the body.
All substances have a degree of toxicity, however, it is the dose used that generates severe damage, an example of this type of substance is poisons and toxic gases.
In the examples of intensive properties, temperature is mentioned, but this can be melting or boiling. In the first case it is the change or transformation of the solid state, which becomes liquid. In the second case, it happens when there are changes from the liquid to the gaseous state. There is also the example of elasticity and this is based on recovering its original shape even when a force has been exerted that, from the first impression, results in the deformity of the body.
"> Loading…Velocity identifies the time by which a substance has changes due to the combination of time and volume. The volume is related to the space that the substance uses regardless of whether it is in a liquid, solid or gaseous state, it is more an extensive and physical property than anything else.
Density is taken as an intensive property and arises from the combination of volume and mass. Viscosity is represented by fluids that are in motion with a tendency to oppose their determined flow. In itself, the viscosity has resistance at the moment of letting the liquid that naturally composes it flow.
In fact, it becomes a sticky substance, a very clear example of this is oil. On the other hand, there is hardness, which is defined as one of the common physical properties in chemical substances.
It represents a total resistance of the material substance to be penetrated by an object, to be scratched or physically altered. It is a hard body, it can be easily interpreted by a mineral. Finally, there is ductility and it is a material substance that has the ability to withstand a lot of force, of course, it tends to deform, but it does not break, not at least completely. It can even stretch a lot until, if it is exceeded in force, it breaks.
As for the extensive properties, there are also a series of practical examples that improve the understanding of the subject. One of them is mass, considered an extremely important physical property because it defines, specifies and studies the amounts of matter existing in a given body.
According to the theory, the body will always have the same amount of mass, however, its weight will vary depending on where it is. Weight is called specific weight and is born from the combination of mass and volume that a body has.
Cohesion forces also have a place in these examples and that is because they are responsible for attracting and holding molecules together. The action of the molecules is to hold together, so that the forces are attractive, cohesive. Finally, the length, which represents the distance between one point and another, even if it is greater than the dimensions of a given surface. To identify the basic units of length, the meter is located, of course depending on the distances to be measured. Each of these examples serve to understand a substance.
Finally, there is an example of a substance that has nothing to do with the chemical aspect and is that of Economic Substance. This term is handled mainly in the economic area and it is nothing other than the administrative identification of all accounting movements and internal modifications that financially affect the public entity and that in turn limit the operations carried out by the System of Government Accounting (SCG).
An example of this economic theory arises when a company sells a good to a third party, this transaction generates a documentation that supports said operation and in which it is indicated that the property has been, indeed, transferred.
