Presentation in physics on the topic "the main provisions of the molecular kinetic theory". Presentation on the topic "the main provisions of the molecular kinetic theory" Main provisions of the MKT presentation

Reason: impacts of liquid molecules on a particle do not compensate each other. The nature of the movement depends on the type of liquid, the size and shape of particles, and temperature. Brownian motion is a chaotic continuous movement of the smallest solid particles suspended in a liquid or gas under the impact of liquid or gas molecules. The nature of the movement depends on the type of liquid, the size and shape of the particles, and the temperature. R. Brown 1827

The relative molecular (or atomic) mass of a substance M r is the ratio of the mass of a molecule (or atom) m 0 of a given substance to 1/12 of the mass of a carbon atom m 0C M r (H 2 O) \u003d 2 1 + 16 \u003d 18 a.u. m. Calculate M r of water H 2 O (for this we use the periodic table) Mendeleev Atomic mass unit (a.m.u.) 1.66 kg

One mole is the amount of a substance that contains as many molecules or atoms as there are atoms in carbon weighing 12 g. 1 mole of any substance contains the same number of atoms or molecules. This number of atoms is designated N A and is called the Avogadro constant in honor of the Italian scientist (XIX century). N A \u003d 6 10 23 mol -1

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Topic of the lesson Basic provisions of the molecular-kinetic theory

The MKT molecular kinetic theory explains the physical phenomena and properties of bodies from the point of view of their internal microscopic structure.

In physics lessons, physical phenomena are studied: mechanical, electrical, optical. In the world around us, along with them, thermal phenomena are common. Thermal phenomena are studied by molecular physics.

1. Molecular physics Molecular physics considers the structure and properties of matter on the basis of MKT.

2. From the history of the development of the MKT The foundation of the MKT is the atomistic hypothesis: all bodies in nature consist of the smallest structural units - atoms and molecules. Period Scientist Theory 2500 years ago Dr. Greece, Leucippus, Democritus of Abdera, was born in the 18th century. M.V. Lomonosov, an outstanding Russian encyclopedic scientist, considered thermal phenomena as a result of the movement of particles that form the bodies of the 19th century. in the works of European scientists finally formulated

M.V.Lomonosov Robert Brown Jean-Baptiste Perrin

The main provisions of the MKT I. All substances consist of the smallest particles (molecules, atoms)

Although the existence of molecules and atoms was established long ago and even their sizes were determined. Only in 1945. A.A. Lebedev, using an "electron microscope", which allows you to examine objects of very small sizes, managed to photograph some large protein molecules (albumin).

A molecule of a substance is the smallest particle of a given substance Molecules are made up of even smaller particles - atoms

Molecule - the smallest particle of matter The dimensions of molecules are negligible.

Each substance corresponds to a certain type of molecule. For different substances, molecules can consist of a single atom (inert gases) of several identical or different atoms, or even of hundreds of thousands of atoms (polymers). Molecules of various substances can be in the form of a triangle, pyramid and other geometric shapes, as well as be linear.

3. Fundamentals of the MKT I. All substances consist of particles Experiments: Mechanical fragmentation Dissolution of matter Compression and stretching of bodies When a body is heated, electron and ion microscopes expand Molecule particles atoms electrons nucleus neutrons protons

Fundamentals of the ILC II. Particles move continuously and randomly Experiments: Diffusion Brownian motion

Diffusion Diffusion is a process of mutual c spontaneous penetration of various substances into each other, due to the thermal motion of molecules. Diffusion occurs in: gases, liquids, solids. Molecular speed: V gas > V liquid > V solid

Diffusion

Diffusion

Diffusion

Why is there a change in the volume of bodies? (hypothesis)

When heated, the volume of the body increases, and when cooled, the solid body liquid gas decreases

Brownian motion (Robert Brown 1827) Brownian motion is the thermal, random motion of particles suspended in a liquid or gas.

The reason: the impacts of liquid molecules on a particle do not compensate each other. The nature of the movement depends on the type of liquid, the size and shape of the particles, and the temperature. Brownian particle

III. Particles, interacting with each other, attract and repel, that is, between them there are forces of attraction and repulsion Experiments: Bonding Wetting Solids and liquids are difficult to compress

If there were no attractive forces between the molecules, then the substance would be in a gaseous state under any conditions, only thanks to the forces of attraction the molecules can be held near each other and form liquids and solids. If there were no repulsive forces, then we could freely pierce a thick steel plate with our finger. Moreover, without the manifestation of repulsive forces, matter could not exist. The molecules would penetrate each other and shrink to the volume of a single molecule.

Interaction of molecules r 0 = d F pr = F from 2. r 0 d F pr > F from r 0 - the distance between the centers of the particles d- the sum of the radii of the interacting particles

The main provisions of the MKT Substance consists of tiny particles Particles of matter are constantly moving randomly Particles of matter interact with each other

Molecules of different substances interact with each other in different ways. The interaction depends on the type of molecules and the distance between them. This explains the presence of various aggregate states of substances (liquid, solid, gaseous)

Particles of matter are constantly and randomly moving.

Aggregate states of matter solid liquid gaseous ice water vapor

Control On what physical phenomenon is the process of salting vegetables, fish, meat based? In which case is the process faster - if the brine is cold or hot? What is the basis for canning fruits and vegetables? Why does sweet syrup acquire a fruity flavor over time? Why can't sugar and other porous foods be stored near odorous substances?

Homework Fill in the table Aggregate state of matter Distance between particles Interaction of particles Nature of particle movement Order of particles Arrangement of shape and volume

2. From the history of the development of the MKT The foundation of the MKT is the atomistic hypothesis: all bodies in nature consist of the smallest structural units - atoms and molecules. PeriodScientistTheory 2500 years ago Dr. Greece Leucippus, Democritus of Abdera was born in the 18th century. M.V. Lomonosov, an outstanding Russian scientist-encyclopedist, considered thermal phenomena as a result of the movement of particles that form the bodies of the 19th century. In the works of European scientists, it was finally formulated

Objectives of the lesson: 1. Formulate the main provisions of the molecular kinetic theory (MKT) 2. Reveal the scientific and ideological significance of Brownian motion 3. Establish the nature of the dependence of the forces of attraction and repulsion on the distance between molecules

3. Fundamentals of the MKT I. All substances consist of particles Experiments: Mechanical fragmentation Dissolution of matter Compression and stretching of bodies When a body is heated, electron and ion microscopes expand Molecule particles atoms electrons nucleus neutrons protons

4. Diffusion Diffusion is the process of mutual penetration of various substances due to the thermal motion of molecules. Diffusion occurs in: gases, liquids, solids. Molecular speed: V gas > V liquid > V solid V liquid > V solid"> V liquid > V solid"> V liquid > V solid" title="(!LANG:4. Diffusion Diffusion is a process of mutual penetration of various substances due to the thermal movement of molecules. Diffusion occurs in: gases, liquids, solids Molecular velocity: V gas > V liquid > V solid"> title="4. Diffusion Diffusion is the process of mutual penetration of various substances due to the thermal motion of molecules. Diffusion occurs in: gases, liquids, solids. Molecular speed: V gas > V liquid > V solid"> !}

6. Interaction of molecules d F pr > F from r 0 - distance between particle centers d-sum of radii of interacting particles "> d F pr > F from r 0 - distance between particle centers d-sum of radii of interacting particles"> d F pr > F from r 0 -distance between particle centers d-sum of radii of interacting particles" title="(!LANG:6. Interaction of molecules particles d is the sum of the radii of the interacting particles"> title="6. Interaction of molecules"> !}

7. Control 1. On what physical phenomenon is the process of salting vegetables, fish, meat based? In which case is the process faster - if the brine is cold or hot? 2. On what phenomenon is the preservation of fruits and vegetables based? Why does sweet syrup acquire a fruity flavor over time? 3. Why can't sugar and other porous foods be stored near odorous substances?