Name: why some substances dissolve in water
Uploaded: 2025-05-22T09:05:33.000Z
Duration: 3 min
Channel: JoVE

K12 Standards

Minnesota Academic Standards in Science

9-12

Chemistry

3.2.1 9C.3.1.1.3

Solubility

Una solución es una mezcla homogénea de dos sustancias principales: el soluto y el disolvente, que está presente en mayor cantidad que el soluto.
En una solución diluida, la proporción de soluto en relación con el solvente es pequeña, mientras que para una solución concentrada, la proporción es grande.
Al formar una solución, el soluto y el solvente no reaccionan químicamente. En su lugar, las moléculas se redistribuyen, con moléculas de disolvente individuales que rodean a las moléculas de soluto e interactúan a través de fuerzas de atracción. Este proceso de disolución se denomina solvatación.
Para favorecer la solvatación, las interacciones soluto-solvente deben ser más fuertes que las interacciones solvente-solvente y soluto-soluto.
En una solución, el soluto y el solvente pueden ser cualquier estado de la materia. La solución en sí misma es una sola "fase".
Lo opuesto a la solvatación es la precipitación, desencadenada por fuertes interacciones soluto-soluto. Cuando la tasa de solvatación es igual a la tasa de precipitación, se establece un equilibrio de solubilidad.
La solubilidad de un soluto es su concentración máxima posible en equilibrio de solubilidad en una cantidad dada de solvente. La solubilidad se ve afectada por la temperatura y otras condiciones físicas como la polaridad molecular.
Los solutos no polares se disuelven en disolventes no polares a través de fuerzas de dispersión de London intermoleculares, mientras que los solutos polares o iónicos se disuelven en disolventes polares a través de interacciones ion-dipolo o dipolo-dipolo.
El agua es un disolvente polar. Los compuestos hidrófilos, o amantes del agua, son solubles en agua debido a las cargas iónicas o grupos polares que permiten interacciones agua-soluto suficientemente fuertes. Son menos solubles en disolventes no polares porque las interacciones soluto-soluto son mucho más fuertes que cualquier posible interacción entre disolventes no polares y moléculas de soluto polar.
Los compuestos no polares solubles en agua y solubles en grasa, como los aceites, son hidrófobos o temen al agua, ya que no pueden formar enlaces de hidrógeno para competir con las interacciones entre disolventes.
Los compuestos anfifílicos o anfipáticos tienen grupos polares y no polares. Por ejemplo, los jabones son sales metálicas de ácidos grasos. En el agua, las moléculas de jabón se agregan en esferas llamadas micelas. Sus colas de ácidos grasos hidrofóbicos no polares apuntan hacia adentro, mientras que sus cabezas hidrofílicas polares están afuera.
Al eliminar las manchas de aceite con jabón, las colas rodean el aceite no polar para formar micelas solubles en agua, lo que permite que el aceite se lave.

solubilidad

Solución, solubilidad y equilibrio de solubilidad


 Una solución es una mezcla homogénea compuesta por un solvente, el componente mayoritario, y un soluto, el componente minoritario. El estado físico de una solución (sólido, líquido o gaseoso) suele ser el mismo que el del disolvente. Las concentraciones de solutos a menudo se describen con términos cualitativos como diluido (de concentración relativamente baja) y concentrado (de concentración relativamente alta).


 En una solución, las partículas de soluto (moléculas, átomos y/o iones) están estrechamente rodeadas por especies de disolventes e interactúan mediante fuerzas de atracción. Este proceso de disolución se llama solvatación. Cuando el agua es el disolvente, el proceso se conoce como hidratación. Para la solvatación, las interacciones soluto-disolvente deben ser más fuertes que las interacciones soluto-soluto y disolvente-disolvente. La precipitación es lo opuesto a la solvatación y ocurre debido a fuertes interacciones soluto-soluto.


 La solubilidad es la medida de la cantidad máxima de soluto que se puede disolver en una cantidad determinada de disolvente. La temperatura, la presión y la polaridad molecular son algunos de los factores importantes que afectan a la solubilidad. El equilibrio de solubilidad se establece cuando la disolución y precipitación de una especie de soluto ocurren a velocidades iguales.


 Lo semejante disuelve a lo semejante


 Para predecir si un soluto será soluble en un disolvente determinado, la regla general es "lo semejante disuelve a lo semejante". Los solutos polares o iónicos se disuelven en disolventes polares debido a las interacciones resultantes ion-dipolo o dipolo-dipolo con las moléculas del disolvente. Esta interacción no será posible con un disolvente apolar. Los solutos no polares se disuelven en disolventes no polares mediante fuerzas de dispersión intermoleculares.


 Compuestos hidrofílicos, hidrofóbicos y anfifílicos


 El agua es un disolvente polar. Los solutos que son solubles en agua se denominan "hidrófilos" o "amantes del agua". Por ejemplo, cuando se agrega KCl sólido al agua, el extremo positivo (hidrógeno) de las moléculas polares de agua es atraído por los iones negativos de cloruro y los extremos negativos (oxígeno) del agua son atraídos por los iones positivos de potasio. Las moléculas de agua rodean los iones K+ y Cl− individuales, reduciendo las fuertes fuerzas que unen los iones y permitiéndoles pasar a la solución como iones solvatados.


 Un soluto que es insoluble en agua se denomina "hidrófobo" o "temeroso del agua". Estos solutos, como el petróleo, no pueden formar enlaces de hidrógeno con las moléculas de agua circundantes debido a las interacciones soluto-soluto más fuertes. Como resultado, las partículas de soluto se agrupan y permanecen sin disolverse.


 Los compuestos que tienen grupos polares y no polares se denominan "anfipáticos" o "anfifílicos". Por ejemplo, los jabones, que son las sales de los ácidos grasos, tienen una cola hidrófoba de hidrocarburos apolares y una cabeza hidrófila polar. La acción limpiadora de jabones y detergentes se puede explicar en función de las estructuras de las moléculas implicadas. El extremo hidrocarbonado (no polar) de una molécula de jabón o detergente se disuelve o es atraído por sustancias no polares, como aceite, grasa o partículas de suciedad. El extremo iónico es atraído por el agua (polar). Como resultado, las moléculas de jabón o detergente se orientan en la interfaz entre las partículas de suciedad y el agua, por lo que actúan como una especie de puente entre dos tipos diferentes de materia, polar y no polar. Como consecuencia, las partículas de suciedad quedan suspendidas en forma de partículas coloidales y se eliminan fácilmente por lavado.

Solubilidad

Solución, solubilidad y equilibrio de solubilidad
Una solución es una mezcla homogénea compuesta por un disolvente, el componente principal, y un soluto, el ...

Education

Educación

JoVE Core

Organic Chemistry

Química Orgánica

Unit 1

Unidad 1

Covalent Bonding and Structure

Enlace covalente y estructura

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

why some substances dissolve in water

Solution formation depends on how solutes and solvents interact. A solution is a homogeneous mixture made of a solvent, which is the larger part, and a solute, which is the smaller part. The physical state of a solution is usually the same as the solvent. Concentration is often described as dilute for a low amount of solute or concentrated for a high amount of solute.

When a solute dissolves, its particles are surrounded by solvent species. This process is called solvation. If water is the solvent, it is called hydration. For solvation to happen, solute-solvent attractions must be stronger than the attractions within the solute and within the solvent. The opposite process is precipitation, which happens when solute particles are pulled together strongly enough to leave solution.

Solubility is the maximum amount of solute that can dissolve in a given amount of solvent. Temperature, pressure, and molecular polarity can all affect solubility. Solubility equilibrium occurs when dissolution and precipitation happen at the same rate. At that point, the amount dissolved stays constant.

A useful rule for predicting solubility is “like dissolves like.” Polar or ionic solutes usually dissolve in polar solvents because of ion-dipole or dipole-dipole attractions. These interactions do not work well with nonpolar solvents. Nonpolar solutes usually dissolve in nonpolar solvents through dispersion forces.

Water is a polar solvent, so substances that dissolve well in water are called hydrophilic, or water-loving. For example, when KCl is added to water, the hydrogen end of water is attracted to chloride ions, and the oxygen end is attracted to potassium ions. Water molecules surround the ions, weaken the forces holding them together, and allow them to move into solution as solvated ions. Substances that do not dissolve in water are called hydrophobic, or water-fearing. Oil is one example. It cannot form hydrogen bonds with water, so the particles cluster together and stay undissolved.

Some compounds contain both polar and nonpolar parts. These are called amphipathic, or amphiphilic. Soaps are an example because they are salts of fatty acids. They have a nonpolar hydrocarbon tail and a polar hydrophilic head. This structure helps soaps and detergents clean because the nonpolar end interacts with oil, grease, or dirt, while the ionic end interacts with water. The molecules line up at the boundary between the dirt and the water. They act like a bridge between polar and nonpolar matter, which helps suspend dirt as colloidal particles so it can be washed away.

Why Some Substances Dissolve in Water

what is organic chemistry?

Carbon Compounds in Everyday Life

Organic chemistry focuses on carbon compounds called organic compounds. These compounds may come from living things or be made by chemists. Carbon is the main element in them, and it bonds with other carbon atoms as well as hydrogen, oxygen, nitrogen, and sulfur. Carbon can form up to four strong bonds. That ability lets carbon atoms build chains and rings of many sizes, shapes, and levels of complexity. Not every carbon-containing substance is classified as organic. Carbonates, cyanides, and...

electronic structure of atoms

Atomic Orbitals and Quantum Numbers

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chemical bonds

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vsepr theory

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solubility

Solution formation depends on how solutes and solvents interact. A solution is a homogeneous mixture made of a solvent, which is the larger part, and a solute, which is the smaller part. The physical state of a solution is usually the same as the solvent. Concentration is often described as dilute for a low amount of solute or concentrated for a high amount of solute. When a solute dissolves, its particles are surrounded by solvent species. This process is called solvation. If water is the...

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key terms and concepts

Learn how solution formation, solvation, solubility, and the rule “like dissolves like” explain why some substances dissolve in water and others do not.

Why Some Substances Dissolve in Water | JoVE K12

organic chemistry

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Arizona Science Standards

High School

Physical Science

HS+C.P1

HS+C.P1U1.4

Molecular Orbital (MO) Theory

Source: Tamara M. Powers, Department of Chemistry, Texas A&#38;M University
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Electron Behavior

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The Arrhenius equation,

relates the activation energy and the rate constant, k, for many chemical reactions.
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Factors Influencing the Rate of Chemical Reactions

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Concentration and Rate Law

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Measuring Reaction Rates

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Temperature Dependence

Chemical Kinetics 
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Reaction Rate

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Concentration Dependence

Chemical Kinetics and the Reaction Rate Law
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Matter and Its Interactions: Develop a model based on evidence to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy. (P: 2, CC: 5, CI: PS1)

9C.3.1.1.2

Solution Formation

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General Properties of Solutions

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Solutions and Concentrations

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Solubility
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Solution, Solubility, and Solubility Equilibrium
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9C.3.2.1.2

3 Developing possible explanations of phenomena or designing solutions to engineering problems
 3.2 Constructing explanations and designing solutions 
  3.2.1 Students will be able to apply scientific principles and empirical evidence (primary or secondary) to explain the causes of phenomena or identify weaknesses in explanations developed by the students or others.

Why Some Substances Dissolve in Water

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