SOLUTE: CHARACTERISTICS AND EXAMPLES - CHEMISTRY - 2024

The solute, in a solution, is the substance that dissolves in the solvent. Generally, the solute is found in a smaller proportion, and can be solid, liquid or gaseous. On the contrary, the solvent is the component of the solution that is found in the most quantity.

For example, in salt water, salt is the solute and water is the solvent. However, not all solutes are solid, nor are solvents liquid.

In this sense, there are several possible combinations of solutes and solvents: gas in liquid, gas in solid, liquid in liquid, liquid in solid, solid in liquid or solid in solid.

To recognize what the solute is in a solution, two aspects must be taken into account. First, the solute is the substance that is in the smallest proportion. In addition, it is the one that changes its physical state (solid, liquid or gaseous) when it is integrated into the solution.

Solutions, solvents and solutes

In chemistry there are homogeneous mixtures, which are those that have their components divided in equal proportions through their content. One of the most common types of homogeneous mixtures are solutions, which are stable homogeneous mixtures of two or more substances, where a solute dissolves in a solvent.

Solutions, solvents, and solutes are seen in day-to-day situations and in settings ranging from industrial to laboratory. These substances formed from mixtures are objects of study due to the characteristics they present and because of the forces and / or attractions that occur between them.

Definition of solute

As noted above, a solute is that substance that dissolves in another, called a solvent.

Usually the solute has a lower proportion and can occur in any of the three states of matter. When a solution occurs between two substances that are in the same phase, the method of choosing the one in the lower proportion is used to define which is the solute and which is the solvent.

The dissolving capacity of the solute will be governed by its solubility. The temperature of the solvent also represents a determining factor when it comes to knowing the possibility of forming a solution or not, since the higher the temperature of the solvent, the greater the amount of solute that can be dissolved in it.

There are substances called surfactants that become less soluble at higher temperatures, but they are exceptions and fulfill specific roles.

The process in which a solvent interacts with a solute to form a solution is defined as solvation, and involves the formation of hydrogen bonds and bonds, as well as attraction by van der Waals forces.

characteristics

Solutes comprise an enormous variety of chemical substances in different states, have different dissolution capacities, and have numerous characteristics that play an important role in the formation of homogeneous mixtures. Some of the main characteristics of solutes are the following:

Solubility

Solubility is the ability of a compound to dissolve in another substance. This capacity is closely related to miscibility, which is the ability of the liquid to mix with another specific one; if they cannot join, it is an immiscibility.

Miscibility has a range more than a specific number, so it can be said that one substance is completely, partially or immiscible in another.

The soluble property of a solute depends in turn on other factors that can increase or decrease this capacity due to their effect on the balance of intermolecular forces that are created between solute and solvent.

Even less expected characteristics, such as the size of a drop of solute or the order in the structure of a crystal, can affect their ability to dissolve.

Temperature

The temperature of the system where a solute is dissolving can affect its solubility: for most solids and liquids, these increase their dissolving capacity according to increases in temperature.

On the other hand, in gases a complex behavior is observed, which is shown as a lower solubility in water at higher temperatures, but a higher one in organic solvents.

Saturation of a solution

The degree to which a solution has dissolved the solute is called saturation of a solution, and the one that has dissolved as much solute as possible is called a saturated solution. From this point on, the added solute will precipitate as an excess to the bottom of the used container; Before this, the solution is called unsaturated.

It is possible to pass the saturation point and continue to dissolve solute, but this requires an increase in temperature. A solution that contains an excess of solute and that has been heated is called a supersaturated solution.

Pressure

Changes in pressure do not usually affect the solubility of solids and liquids, apart from some exceptional cases (accumulation of calcium sulfate in oil pipes), but in gases it is a determining factor of their ability to dissolve.

In fact, the solubility of a gas in a solvent is directly proportional to the partial pressure of that gas on said solvent.

Polarity

The polarity of a solute is crucial when measuring its dissolution capacity; a solute will dissolve better in a solvent with a chemical structure similar to the one it has.

For example, highly polar or hydrophilic substances will have greater solubility in highly polar solvents, while they will be practically insoluble in non-polar substances.

Similarly, intermolecular forces play an important role in solvation and the ease with which a solvent can dissolve a solute: the higher the dipole-dipole forces, hydrogen bonds, and other bonds, the greater the solvent's ability to dissolve the solution. solute and form a solution.

Differences between solute and solvent

- The solute is the substance that is dissolved; the solvent is the medium for dissolving the solute (s).

- The solute can be found in a solid, liquid or gaseous phase; the solvent is usually in the liquid phase, but it also exists as a solid and a gas.

- The solubility of the solute depends more on properties such as the surface; the ability to solvatar depends on polarity, temperature and pressure, among other factors.

- The solute is usually the desired component to be extracted in industrial processes; solvent is usually not the desired component and is disposed of in industrial processes.

Examples of solute

- Sugar is an example of a solid phase solute, typically used to sweeten water.

- Hexane can be found in paraffin wax, serving as a liquid solute that makes this solid more malleable.

- Carbon dioxide is a gas added to drinks to make them fizzy.

Solutes in the gaseous state

Carbon dioxide in water (soft drinks)

Carbonated water is water that contains carbon dioxide and is produced by passing carbon dioxide under pressure through water.

Carbonated mineral waters have occurred naturally for a long time. These effervescent waters exist due to excess carbon dioxide in an aquifer that has dissolved under pressure.

One of the best known examples of solute is commercial soft drinks, which are combined with a syrup.

The presence of carbon dioxide makes these waters and soft drinks more appetizing and visually attractive.

Oxygen and other gases in nitrogen (air)

The air in the atmosphere is made up of molecules of different gases. It basically consists of 78% nitrogen and around 21% oxygen (solute). Also, it contains almost 1% argon and other molecules, but in very small amounts.

Propane in butane (cooking gas)

This combination, also known as liquefied petroleum gas (LPG), began to be used as early as 1860 as a source of fuel for household purposes.

Since then it has expanded its production and consumption for both domestic and industrial use. Because both gases are extremely odorless and dangerous, a substance called mercaptan is added to it, making any leaks noticeable.

Solid state solutes

Zinc on copper (brass)

The commercial alloy known as brass is made up of zinc (5 to 40%) dissolved in copper. Zinc helps increase tensile strength. Other elements such as tin, iron, aluminum, nickel and silicon can be added to this alloy.

Iodine in alcohol (tincture of iodine)

Another popularly known example of solute is tincture of iodine. This solution contains iodine in ethyl alcohol (44 to 50%). Tincture of iodine is used as an antiseptic.

Salt in water (sea water)

Seawater covers more than 70% of the Earth's surface. This is a complex mixture of 96.5% water, 2.5% salts, and smaller amounts of other substances. This includes dissolved inorganic and organic materials, particulates, and some atmospheric gases.

Solutes in liquid state

Alcohol in water (alcoholic beverages)

Ethanol or ethyl alcohol (solute) from the fermentation of sugar is mixed with water in fixed proportions to produce alcoholic beverages.

This compound is easily digested by the body, but its consumption in excess can cause serious damage to health.

Water in air (humidity in air)

Water in air is commonly known as fog. This is caused by small drops of water suspended in the air, and is basically due to the cooling of the earth at night.

In this way, this cooling causes the surrounding air to lower its temperature. Then, the phenomenon occurs when the water retained in it condenses.

Acetic acid in water (vinegar)

Vinegar is a sharp-tasting liquid used to add flavor or preserve food. It is prepared by a solution of acetic acid mixed with water.

The acetic acid concentration is variable. For example, distilled vinegar has a proportion that ranges from 5 to 8%.

Mercury in silver (dental amalgams or fillings)

The amalgams used for dental fillings are made up of 2% mercury with an alloy that acts as a solvent. This alloy contains 70% silver. Tin, copper and zinc can also be added.

Solutes that can be used at home

Sugar in water

Sugar is a molecular and polar compound, and as such it has the ability to dissolve in water, which is also a polar element.

The way the sugar is structured will vary the dissolving process. For example, if the sugar is in lumps it will take longer to dissolve than if it is in grains.

Some experts consider sugar water to be a very important source of energy for the body. There have even been studies that reveal the effectiveness of this solution in people who do physical activity.

Sugar in flour

It is common for the preparation of a cake to mix the solid ingredients first, and then add the liquids.

Sugar is a solute that binds with flour, making the base mix for the cake. In addition to these two ingredients, others are also added later, such as eggs, butter or vanilla.

This type of solute is solid and, in this case, it is mixed with a solvent that is also solid. The resulting base can also be used to make sweet breads, cookies, cakes, cakes, cupcakes and many other sweet foods.

Powdered juice in water

There is a great supply of powdered juices that are prepared by dissolving this element in water. In this case the solute is the powdered juice and the solvent is water.

The amount of solvent must be greater than that of solute, so one or two tablespoons of powdered juice is usually dissolved in a glass of water. There are even some powders whose concentration is higher and a smaller quantity should be used.

There are detractors of these juices, since they indicate that the components they include (such as preservatives, stabilizers and sweeteners, among others) are harmful to health.

Chlorine in water

One way to make water drinkable is by using chlorine as a solute dissolved in water. This disinfectant is characterized by being one of the most used to eliminate microbes, and is ideal for converting non-potable water into potable water in a fast, economical and easy way.

Chlorine as a solute in this solution must be incorporated into the water in a concentration no greater than 0.2 and 0.5 milligrams per liter.

The amount of chlorine to be used should be very little, because this substance can be extremely toxic when consumed or exposed to large amounts.

This method of purifying water is known as chlorination, and can be applied in the middle of a mountain excursion or to treat household water, in order to eliminate bacteria and microbes that may be found in the pipes through which the water passes.

Paint in water

Water is the most universal solvent there is, and it is also the base on which a solute like paint can dissolve.

Paint usually dissolves for a number of reasons. The most common is to facilitate the cleaning of brushes and other tools used for painting.

There are many types of paintings; those that dissolve best in water are those made of latex. In addition to allowing better cleaning of the tools, the advantage of diluting the paint in water before starting to paint is that it will guarantee a better finish on the painted surface.

Powdered milk in water

Powdered milk is a solute that is formed through the dehydration of milk that has already been pasteurized. The purpose of this process is to ensure that the milk can be preserved better for longer.

This solute dissolves in water and generates the liquid milk that is commonly ingested for breakfast, along with coffee or in various preparations.

As in the case of powdered juice, the amount of milk to be diluted must be less than the amount of water in which the solution is to be prepared.

Detergent in water

When washing clothes, use liquid or powder detergents. These dissolve in water to form a solution that acts as a disinfectant and cleaner for textile fabrics.

The amount of solute to be used in this solution is variable, it will depend on the type of detergent, its presentation and its components.

The solution made up of detergent and water can be very polluting when it comes into contact with water dumps, so it is advisable to use biodegradable detergents, which can degrade in a very short time and affect the environment much less.

Jelly

Gelatin is an element made up of tendons, ligaments and bones of animals. This compound can be presented in powder or in sheets.

In both cases, this solute must be dissolved in hot water to achieve the end result: an ideal sweet food for a dessert and with many health benefits.

Among the benefits of this compound, it stands out that it favors rapid tissue repair and is an anti-inflammatory food. In addition, it has a large amount of protein and plays an important role in fortifying the immune system.

Eating a little daily amount of gelatin will help to regenerate the joints and thus prevent the onset of osteoporosis.

Chocolate in milk

Chocolate is an element that is formed thanks to the mixture of cocoa and cocoa butter. This food works as a solute when mixed with milk to prepare what is commonly known as hot chocolate.

For this preparation, the desired amount of milk is heated and the chocolate is added, in pieces, powder or liquid, stirring constantly.

For this solute to dissolve in the best possible way and avoiding lumps, it is necessary to beat the mixture without pause.

Cocoa powder in water

You can also make hot chocolate using cocoa powder. This solute is formed solely by the mass of powdered cocoa. Unlike chocolate, cocoa does not include the butter of this fruit.

Cocoa can be perfectly dissolved in water to create a chocolate-flavored drink. In these cases, it is essential to sweeten the mixture with sugar, honey or some sweetener; otherwise the result will be extremely bitter.

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