Understanding of intermolecular forces 10

The intermolecular forces are divided into gravitational and repulsive forces.

We know that there are three types of object forms: solid, liquid, and gaseous. This can be understood as the difference in the distance between molecules due to the difference in the frequency of molecular motion.

The composition of glass is mainly silica, which is generally solid at room temperature, and is not easy to chemical reactions with other substances at room temperature.

It is mainly explained around the fact that silica is a solid.

Silica is a silicon 4+ atom and two oxygen 2-atoms, glass is made of a large amount of silicon dioxide aggregated, the trajectory of electrons affects their distance, resulting in molecular size, temperature is the expression of energy in the general form of electrons, almost all objects have the phenomenon of thermal expansion and cold contraction, this is the effect of temperature (electron energy) on the distance between the molecules of the object.

If the two pieces of broken glass are put together, there is air at the interface, which can not be closed tightly, and the range of movement of the molecules in the air is larger, so that the force between the broken glass is weak, and the gap between the glass can be reduced with water to achieve a better effect. And when the glass is broken, it is generally uneven force or uneven heating, at this moment the distance between some molecules is too large, the energy is too high, and smaller fragments will fly out at the same time as the shattering, they have a very high speed, so the glass should release energy when it is broken.

Energy + Intact Glass = Broken Glass + Energy This process is reversible, but the form of energy is not necessarily the same for both.

There is a chapter in the physics textbook about molecular motion, there should be an experiment on the molecular motion of two metal sheets, which foreigners do, to show that molecules are always moving.

The intermolecular forces can be described in terms of gravitational force.

In summary, the reason why the broken glass cannot be put together is that there are other kinds of molecules between the same molecules, which increases the distance between the same kind of molecules, resulting in the almost complete disappearance of the force between the same kind of molecules at the gap.

Can't be put together. Because the intermolecular distance of the broken glass is too large, it exceeds the range of intermolecular forces. How can we calculate intermolecular forces?

Broken glass cannot be reduced because the intermolecular distance is too large, and the intermolecular force is negligible.

The molecule has broken and cannot be repaired.

Intermolecular forces: Dispersion force, induction force, orientation force. Intermolecular forces, dispersion forces, and the force of attraction that arises between instantaneous dipoles and instantaneous couple beam poles.

An instantaneous dipole, a dipole produced by the fact that the centers of positive and negative charges of molecules do not coincide at a certain moment. Dispersion forces are prevalent between all molecules. Induced force, the force of attraction generated between the intrinsic dipole and the induced dipole.

Induced dipoles, as the molecules are subjected to an external electric field, including polar molecules.

A dipole resulting from the influence of an intrinsic dipole field.

Interactions between moleculesThere are both gravitational and repulsive forces between molecules, and the intermolecular forces decrease with the increase of the distance between molecules, but the law of decrease is different. When the intermolecular distance is equal to the equilibrium distance, the gravitational force is equal to the repulsion force, and the intermolecular force is zero, when the intermolecular distance decreases, both the gravitational force and the repulsion force increase, and the repulsion force changes faster, which is manifested as the repulsive force, and when the intermolecular distance increases, both the gravitational force and the repulsion force decrease, and the repulsion force changes rapidly, which is manifested as the gravitational force.

Question 1: Interaction forces between molecules.

Including gravity and repulsion, both of which are related to the spacing between molecules, and the greater the distance, the smaller the gravitational force and the repulsion force, but the speed of change is different.

At a certain spacing r0, the magnitude of the two is equal, and when it is less than this spacing, the gravitational force is less than the repulsive force, which is mainly manifested as repulsive force. When greater than this spacing, the gravitational force is greater than the repulsive force, which is mainly manifested as the gravitational force.

The relationship between the magnitude of the two and r and the relationship between the resultant force of the two and r are shown in the following figure:

Molecular potential energy. The reason why it exists is because there are intermolecular forces, and if you ignore the intermolecular forces, the molecular potential energy is 0.

If you don't understand, please ask!

Intermolecular forces, also known as:Van der Waals Force（van der waals force）。There are three sources of intermolecular forces (van der Waals forces):Polar moleculesof permanenceDipole momentinteraction.

One polar molecule polarizes the other, creating an induced dipole moment and attracting each other. The movement of electrons in a molecule produces an instantaneous dipole moment, which instantaneously polarizes neighboring molecules, which in turn enhances the instantaneous dipole moment of the original molecule; This mutual coupling produces an electrostatic attraction effect, and the contribution of these three forces is different, with usually the third action contributing the most.

Intermolecular forces exist only between molecules or noble gases.

noble gas) atoms, also known as van der Waals forces.

van der waals), which is additive, is a secondary bond.

The relationship between the three forces:

Between polar molecules and polar molecules, orientation forces, induction forces, and dispersion forces all exist; Between polar molecules and non-polar molecules, there are induction and dispersion forces; Between non-polar and non-polar molecules, only dispersion forces exist.

The proportional magnitude of these three types of forces is determined by the polarity and deformability of the interacting molecules. The greater the polarity, the more important the role of the orientation force; The greater the deformability, the more important the dispersion force is; Induction is related to both factors.

But for most molecules, the dispersion force is the main one. Experiments have shown that for most molecules, dispersion forces are dominant; Only molecules with a large dipole moment (e.g., water) are the main orientation force; And the induction force is usually very small.

The polar circle is a reflection of the electron cloud in the molecule.

Whether it is easy to deform. Although van der Waals forces are only, the interactions between a large number of macromolecules become very stable. For example, C—H has 7 kJ mol in van der Waals in benzene and 7 kJ mol in lysozyme.

Van der Waals force, a sugar-bound substrate, has 60kj mol, and van der Waals force has additivity.

The above content reference: Encyclopedia - Intermolecular Orange Force.

Intermolecular forces include induction, dispersion, and orientation. The intermolecular force only exists between molecules or between atoms of noble gas, also known as van der Waals force, which has additivity and belongs to secondary bonds.

Definition: The van der Waals force (also known as the molecular force) arises from the electrostatic interaction between molecules or atoms. The empirical equation for the calculation of its energy is:

u=b r12-a r6 (for 2 carbon atoms, the parameter value is b=; a=；When two atoms are close to each other and overlap each other, strong repulsion occurs, and the repulsive force is inversely proportional to the distance to the 12th power. The low point in the figure is the distance maintained by the van der Waals force, which is called the van der Waals radius. The molecular gravitational force is inversely proportional to the distance to the 6th power, and the molecular repulsion force is inversely proportional to the distance to the 12th power.

Van der Waals forces can be further divided into three types of forces: induction, dispersion, and orientation.

1. Induced force is an intermolecular force. Under the intrinsic dipole induction of a polar molecule, the molecule adjacent to it will produce an induced dipole, and the electrical gravitational force between the induced dipole between the induced dipole and the intrinsic dipole between the molecule is called the induced force. There is an induction force between polar and non-polar molecules and between polar and polar molecules.

2. When the non-polar molecules are close to each other, a very weak force of attraction will be generated between their instantaneous dipole moments, which is called dispersion force. The dispersion force is present between all the molecules. In any molecule, there is an instantaneous dipole, and this instantaneous dipole will also induce neighboring molecules to produce an instantaneous dipole, so that the two molecules can be attracted to each other by the instantaneous dipole.

This instantaneous dipole force is called dispersionforce.

3. The orientation force, also known as the directional force, is the electrostatic attraction between the intrinsic dipole and the intrinsic dipole between polar molecules and polar molecules, which is called orientation force, also known as directional force. Because when two polar molecules are close to each other, the same poles repel each other, and the opposite poles attract, so that the molecules rotate relatively, and the polar molecules are arranged in a certain direction and attracted to each other by electrostatic gravity.

The intermolecular forces include dispersion forces, induction forces, orientation forces, etc.

1. Dispersion force, the morphological attraction generated between the instantaneous dipole and the instantaneous dipole. Instantaneous dipole, a dipole produced by the fact that the center of positive and negative charge of the molecule does not coincide at a certain moment, the dispersion force is universal between all molecules. Between non-polar molecules and non-polar molecules, there is only dispersion force.

2. Inducing force, the force of attraction generated between the intrinsic dipole and the induced dipole, inducing the induced dipole refers to the source pole, a dipole produced by the influence of the molecule by the external electric field, including the intrinsic dipole field of the polar molecule. The induced force exists between polar molecules and non-polar molecules, and between polar molecules and polar molecules. Between non-polar molecules and polar molecules, there is a dispersion force and an inductive force.

3. The orientation force, the attraction generated between the intrinsic dipoles, the orientation force exists only between polar molecules and polar molecules. Intermolecular forces (van der Waals forces) are a general term for dispersion forces, inducing forces, and orientation forces. Intermolecular forces are much weaker than general chemical bonds and have no directionality and saturation.

Between polar molecules and polar molecules, there are dispersion, induction, and orientation forces.

Categories: Science & Engineering.

Problem description: Is intermolecular gravitational force "gravitational force"? Is repulsion a "repulsion force of the same charge"?

Analysis: The intermolecular force, also known as van der Waals force, is divided into three parts: (1) orientation force; It is the force generated by the directional arrangement of the dipole between the polar molecule and the polar molecule (2) The inducing force is when the polar molecule is close to the non-polar molecule, the dipole of the polar molecule deforms the non-polar molecule, and the dipole produced is called the induced dipole. The force produced by the attraction of the intrinsic dipole between the induced dipole and the polar molecule is called the induced force (3) Dispersion force, which refers to the fact that the electrons and nuclei in each molecule are in continuous motion, so the instantaneous relative displacement between the electron cloud and the atomic nucleus often occurs, resulting in the instantaneous dipole, and the two instantaneous dipoles must be in a state of adjacent to the opposite poles, and the mutual attraction is called the dispersion force.

The intermolecular force has three characteristics: (1) generally only a few to dozens of kj*mol than or comic chemical bond energy is 1-2 orders of magnitude smaller, (2) the force shirt is desperate to sell a range of several hundred pm, generally not directional and saturated. (3) For most molecules, the dispersion force is the main one, and only the polar molecular orientation force accounts for a large proportion, and the induction force is often small.

The concepts of gravitational force for macrocosm and intermolecular force for microcosm are two different domains of definition that cannot be confused.

Intermolecular forces, also known as van der Waals forces. It is a weakly basic electrical force of attraction that exists between neutral molecules or atoms. Here's the details I've put together, let's take a look!

Intermolecular interaction force refers to the ability of different molecules to attract and even associate with each other, and this force is called intermolecular interaction force. There are many kinds of intermolecular interaction forces, which have an important impact on the physical, chemical and biological properties of compounds, and the most common dipole-dipole interactions, dispersion forces and hydrogen bonds are all interaction forces.

A chemical reaction is the process by which old bonds break and new bonds are formed. Organic reactions can be classified into different types according to the way they resist or covalent bond breakage. If a pair of electrons formed by a bond are divided equally between two bonding atoms or groups at the time of covalent bond breakage, this type of cleavage is called homocleavage.

Atoms or groups containing unpaired electrons produced by homocleavage are called free radicals.

1.Van der Waals

The van der Waals force is a ubiquitous intermolecular force that is weak, 1 2 orders of magnitude smaller than the bond energy of a chemical bond.

For structurally similar substances, the greater the relative molecular mass, the greater the van der Waals force. The greater the polarity of the molecule, the greater the van der Waals force.

The van der Waals force mainly affects the physical properties of the substance, and the greater the van der Waals force, the higher the melting and boiling point of the substance. Take the acres of Xiang.

2.Hydrogen bonding

Hydrogen bonding is the force between a hydrogen atom that has formed a covalent bond with a very electronegative atom (like hydrogen in a water molecule) and another molecule that is very electronegative (like oxygen in a water molecule).

Hydrogen bonding exists only between molecules with strong polarity H-F, H-O, H-N covalently bonds, or within more complex molecules. Except for f, o, n, there are generally no hydrogen bonds formed between other atoms and hydrogen atoms.

Hydrogen bonding is divided into intermolecular hydrogen bonding and intramolecular hydrogen bonding.