EMPIRICAL SOLUTIONS: CHARACTERISTICS, PREPARATION AND EXAMPLES - CHEMISTRY - 2025

The empirical solutions are those where the exact amounts of solute and solvent are not defined or reproduce. The relationship between the amount of solute and solvent in these solutions is not quantitatively determined; therefore, they lack a known concentration.

The empirical solution, as the word 'empirical' indicates, is the product of practice, of the experience of the person preparing the solution. These solutions are also known as qualitative solutions.

Kiwi juice: an example of an empirical solution. Source: pexels.

During the preparation of a kiwi juice, a variable volume and number of slices are added, depending on the size of the jar or how many diners are waiting to quench their thirst.

The amounts of solute (kiwi and sugar) and solvent (water) used in the preparation are based on the judgment or experience of the person preparing the solution. Likewise, the preparation of this empirical solution is subject to taste criteria; if the person prefers it sweeter, add half a cup more sugar.

The components of kiwi juice therefore lack a defined or known concentration such as that found in standard solutions. Furthermore, this juice cannot be expressed with any of the units of concentration, physical or chemical; unless all ingredients are properly weighed and measured.

Empirical solutions do not have a common, important application in industry or science. The preparation of empirical solutions is occasional in chemistry, such as in dissolution media tests.

Characteristics of empirical solutions

Among the characteristics that can be attributed to empirical solutions are the following:

-They are usually prepared in informal places, such as in homes, restaurants, soda fountains, bars, among other similar places.

-Anyone can prepare them, without specific training in chemistry, or previous experience in a laboratory.

-The preparation of these solutions is carried out to satisfy or cover any need, generally culinary, food, among others.

-During the preparation of these solutions, the experience, practice, criteria, need or taste of those who prepare them prevail.

-They are prepared without following any weighing method, without the need for stoichiometric calculations, or instrumental equipment; like the pH meter, for example.

-In its preparation, volumetric materials are not used, since it is not essential to have exact measurements of the volumes of solvents or liquid solutes.

-Its preparation in general is rare in routine and research laboratories, where titrated solutions are usually required.

-The empirical solutions that are most frequently prepared in homes are solutes dissolved in liquids. The mixture of liquids in liquids is also frequently prepared, in the preparation of cocktails, for example.

Types or classification

The classification of empirical solutions is similar to that of valued solutions when expressed qualitatively or informally. It is already clear that the amount of solute and solvent in these solutions is not exactly determined.

When considering the solubility and amount of solute that is added to the solvent, empirical solutions can be diluted or concentrated. Likewise, concentrated empirical solutions can also be classified as unsaturated, saturated, or supersaturated.

An instant drink can be prepared either diluted or concentrated, according to the taste or need of the diner.

Dilute solution

It is that solution in which little amount of solute has been added in relation to the amount of solvent present. The taste of the resulting solution, the color obtained, among other criteria, will indicate how dilute or concentrated the solution is. An example of this solution could be placing a little diluted sugar in a cup of water.

Concentrated solution

They are those solutions that have an abundant or high amount of solute with respect to the amount of solvent in the solution. An empirical solution is concentrated by adding more solute or decreasing the volume of the solvent.

Unsaturated solution

It is that solution in which the amount of the solute is high without saturating the solution; therefore, even more solute can be dissolved without the formation of a precipitate.

Saturated solution

It is that solution in which the maximum amount of solute that the solvent can dissolve has been added. In the prepared solution no more solute will dissolve in the solution solvent.

Supersaturated solution

It is that solution that has been prepared with an amount of solute that exceeds the limits or dissolution capacity of the solvent. Only by increasing the temperature can the solubility of the solute be increased.

Preparation

As indicated in previous paragraphs, in the preparation of empirical solutions, the tastes of the person preparing the solution will prevail. The amount of solute, as well as the amount of solvent, will depend on individual, personal criteria and requirements.

No solute weighing will be used in its preparation, and therefore the units of measurement are numerically non-existent.

materials

Utensils such as spoons can be used, poured into containers that will also lack a volume indicator; glasses or jugs, or even wisps added from the fingers or a tight amount in the fists.

Coffee, cocktails and tea

The empirical solution can contain one or more substances dissolved in a certain amount of solvent. Like coffee, for example, in addition to water and coffee, sugar is usually added as a sweetener.

On the other hand, it can also consist of a mixture of liquids, such as cocktails, for example. Various liquors are mixed to prepare this type of empirical solution, and in the absence of metrics, the skill of preparing the same drink with the same flavor is put to the test countless times.

It can be prepared with solids such as green tea, or other spices, that infuse the solvent with its taste and smell. An empirical solution is prepared once this preparation is cast, or passed through a sieve, leaving the solution homogeneous.

Examples

There are numerous examples that can be given of empirical solutions, routinely prepared at home or very occasionally in laboratories.

Preparation of beverages

At home, in restaurants and in other food outlets, drinks are being prepared daily and continuously or routinely. There are many instant drinks, such as tea, or chocolate drinks, whose criteria are the taste and taste of people.

Coffees, lemonades, teas, milk chocolate, coffee with milk, cocktails, guarapitas, among other drinks, are continuously prepared.

Dissolution media tests

In chemistry, empirical solutions are prepared by performing some dissolution media preparation tests.

An example could be when you have an organic compound P and you want to study its solubility in different solvents. From the qualitative results, which are empirical solutions, a specific dissolution medium can be prepared.

Tests are carried out with dissolution media for this compound, without the need to use volumetric material for its preparation.

In this medium, solvents or reagents are added to the point that an appropriate dissolution of P. is achieved. From these previous measurements, the same procedure is carried out to dissolve other solids of the same nature of P.

The concentration of these reagents needed to reproduce the dissolution medium can then be estimated; and with this, it is no longer an empirical solution.

Ice bath

Empirical solutions can be prepared when using ice or cryoscopic baths to maintain a substance or reaction medium at low temperatures. The person who prepares it adds an uncertain amount of ice, salt and water, in order to cool enough the container or material placed inside the bath.

Use of pH indicators

Another example is when solid acid-base indicators are added to a sample that will undergo a volumetric titration. If the indicator already exhibits color at the pH of the sample, add an amount such that the intensity of its color does not interfere with the end point (indicator shift) in the titration.

This occurs, for example, when working with the eriochrome T black indicator. Its solid consists of black crystals that intensely color the sample to be titrated. If too much of this indicator is added, the solution will turn dark blue, making it impossible to see the end point.

Bicarbonate solution

Bicarbonate for acid burns: add such an amount of bicarbonate to water until it is saturated.

When this solution is not prepared prior to the accident, a deliberate amount of this salt is added to the water with the sole objective of neutralizing the acid or base in the affected area of ​​the body.

Christmas decorations

When balloons with colorful solutions (transition metal compounds, dyes, etc.) are improvised to decorate laboratories in December times, empirical solutions are being used (unless they have been prepared quantitatively).

Final reflection

As a final reflection, in the laboratory there are very few occasions where empirical solutions are worked (and much less at an industrial level).

This is because it is essential to be able to reproduce the solutions perfectly. Furthermore, the accuracy and precision of the measurements cannot be sacrificed; since, the veracity and quality of the experimental results would be reduced.

References

1. Whitten, Davis, Peck & Stanley. (2008). Chemistry. (8th ed.). CENGAGE Learning.
2. Expressing Concentrations. (sf). Recovered from: chem.purdue.edu
3. Zapata, M. (2016). Concentration of solutions: Qualitative solutions. Recovered from: quimicaencasa.com
4. Wikipedia. (2019). Dissolution. Recovered from: es.wikipedia.org
5. Andrade C. Guevara. (2012). Empirical solutions.. Recovered from: roa.uveg.edu.mx