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What are the Van der Waals forces?

Van der Waals forces

In chemistry, allusion is given to a sub-branch of physicochemistry called Van der Waals interaction or forces , which thanks to them we can explain the adhesion , friction , diffusion , surface tension and viscosity of different organic compounds. For example: we know because naphtha is a liquid, methane is a gas and polyethylene, which is represented as a polymer made up of C and nothing else, is a solid.

Van der Waals forces

What are the Van der Waals forces?

In physicochemistry, it is represented as an interaction or force both repulsive and attractive between the different molecules due to a bond between them called intramolecular bond (covalent bond of molecular type, ionic bond or metallic bond), or the interaction of ions through electrostatics with neutral molecules.

  • Definition
  • History of the Van der Waals forces
  • Types
  • Applications of Van der Waals forces
  • Importance
  • Examples
  • Van der Waals forces in the water

Definition

It is a force that is characterized by generating a molecular stabilization where there is the formation of a non-covalent chemical bond where two types of forces or interactions participate; one of them is the dispersion force represented as an attractive force and the other is the repulsion force between electronic shells of two consecutive atoms.

History of the Van der Waals forces

In the 19th century, the American physicist Willard Gibbs was considered the founding father of a sub-discipline of chemistry called, physical or physicochemical chemistry where he conducted studies on the balance of heterogeneous substances   in 1876 in his publication On the Equilibrium of heterogeneous Substances.

The Van der Waals forces named after the Dutch physicist Johannes Diderik Van der Waals (1837-1923); In 1873 he was the pioneer in introducing the effects of equations in the state of a gas, awarding him the Nobel Prize in Physics in 1910.

Types

  • Orientation : it is the interaction of a permanent dipole with a permanent dipole.
  • Induction : it is the interaction of a permanent dipole and an induced dipole.
  • Dispersion : also known as London forces , it is the interaction of an instantaneous dipole with an instantaneous dipole.

Applications of Van der Waals forces

  • They define the solubility of the lower alcohols.
  • They define the solubility of higher alcohols through the properties of the polar alkyl radical.
  • Electrostatic interaction, also known as Keesom interaction .
  • Electrochemical polarization called induction , this interaction is measured in debyes in honor of Peter Debye .

Importance

Although Van der Waals forces in many contexts are relatively weak compared to normal chemical bonds , they play a widely based role in the variability of fields such as supramolecular chemistry, structural biology , polymer science, nanotechnology. , surface science and the physics of condensed matter.

Examples

Given the following substances: NO, CCI 4 and C 8 H 18

  • Explain the type of intermolecular force that each one presents

NO> polar: Van der Waals

CO 4 and C 8 H 18 > apolar: London forces

  • Indicates the state of aggregation that can be expected to be expected under ambient conditions

NO> gas

CO 4 and C 8 H 18 > liquid since the molecular masses are large 154 and 114

Van der Waals forces in the water

The molecules that are dispersed in water are attracted to each other by points of electrostatic forces that are described as Van der Waals forces on liquid surfaces, and even non-polar molecules experience some Van der Waals forces in water. ; to what is associated with the fact that they are polar molecules.

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