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How are particles in solids, liquids and gases located?

This material not only tells how the particles are arranged in solids, but also how they move in gases or in liquids. The types of crystal lattices in various substances will also be described.

State of aggregation

There are certain standards that indicate the presence of three typical aggregate states, namely: solid, liquid and gas.

Define the components for each aggregate state.

  1. Solids are practically stable in volume and shape. The latter change is extremely problematic without additional energy costs.
  2. The liquid can easily change shape, but still retains its volume.
  3. Gaseous substances do not retain form or volume.

The main criterion by which the aggregate state is determined is the location of the molecules and the ways of their movement. In a gaseous substance, the minimum distance between individual molecules is much larger than themselves. In turn, the molecules of liquid substances do not disperse over long distances in the usual conditions for them and retain their volume. The active particles in solids are arranged in a strictly defined order, each of them, like a pendulum clock, moves about a certain point in the crystal lattice. This gives the solids special strength and rigidity.

Therefore, in this case, the most relevant question is how the active particles are located in solids. In all other cases, the atoms (molecules) do not have such an ordered structure.

Fluid Features

It is necessary to pay special attention to the fact that liquids are a kind of intermediate link between the solid state of the body and its gaseous phase. Thus, as the temperature is lowered, the liquid solidifies, and when it rises higher than the boiling point of the substance passes into a gaseous state. However, the liquid has common features with both solid and gaseous substances. So, in 1860 the outstanding domestic scientist DI Mendeleyev established the existence of the so-called critical temperature - absolute boiling. This is the value at which the thin boundary between the gas and matter in the solid state disappears.

The next criterion, which combines two neighboring aggregate states, is isotropy. In this case, their properties are the same in all directions. The crystals, in turn, are anisotropic. Like gases, liquids do not have a fixed shape and occupy the entire volume of the vessel in which they are located. That is, they have low viscosity and high fluidity. Faced with each other, the liquid or gas microparticles make free movements. It used to be that in the volume occupied by the liquid there is no ordered molecular motion. Thus, liquid and gas were opposed to crystals. But as a result of subsequent studies, the similarity between solid and liquid bodies was proved.

In the liquid phase at a temperature close to solidification, the thermal motion resembles the motion in solids. In this case, the liquid can still have a certain structure. Therefore, when we answer the question of how particles are arranged in solids in liquids and gases, we can say that in the latter, the motion of molecules is chaotic, disordered. But in solids molecules occupy in most cases a definite, fixed position.

The fluid is a kind of intermediate element. And the closer its temperature to boiling, the more molecules move as in gases. If the temperature is closer to the transition to the solid phase, the microparticles begin to move more and more orderly.

Change in the state of substances

Consider the simplest example of a change in the state of water. Ice is a solid phase of water. Its temperature is below zero. At a temperature of zero, the ice begins to melt and turns into water. This is explained by the destruction of the crystal lattice: when heated, the particles begin to move. The temperature at which the substance changes the aggregate state is called the melting point (in our case it is 0 for water). Note that the temperature of the ice will remain at one level until it melts completely. In this case, the atoms or molecules of the liquid will move in the same way as in solids.

After that we will continue to heat the water. The particles begin to move more intensively until our substance reaches the next point of the change in the aggregate state-the boiling point. Such a moment occurs when the bonds between the molecules that form it are broken off due to the acceleration of motion-then it acquires a free character, and the liquid under consideration passes into the gaseous phase. The process of transformation of a substance (water) from a liquid phase to a gaseous one is called boiling.

The temperature at which water boils is called the boiling point. In our case, this value is equal to 100 degrees Celsius (the temperature is dependent on the pressure, the normal pressure is one atmosphere). Note: until the existing liquid completely and completely turns into steam, its temperature remains constant.

It is also possible to reverse the process of water transfer from the gaseous state (vapor) to a liquid, which is called condensation.

Then you can observe the process of freezing - the process of the transition of a liquid (water) into a solid form (the initial state is described above is ice). The processes described above make it possible to obtain a direct answer to how the particles are arranged in solids, in liquids and gases. The location and state of the molecules of a substance depends on its aggregate state.

What is a solid body? How do microparticles behave in it?

A solid body is a state of a material medium, the distinctive feature of which is the preservation of the constant shape and the constant nature of the thermal motion of microparticles, which perform insignificant fluctuations. The bodies can be in a solid, liquid and gaseous state. There is also the fourth state, which modern scientists tend to attribute to the number of aggregates - this is the so-called plasma.

So, in the first case, any substance, as a rule, has a constant unchanged shape, and this has a key effect on how the particles are arranged in solids. At a microscopic level, it can be seen that the atoms that make up a solid are connected to each other by chemical bonds and are located at the nodes of the crystal lattice.

But there is an exception - amorphous substances that are in a solid state, but the presence of a crystal lattice can not boast. It is from this that we can answer the question of how the particles are arranged in solids. Physics in the first case indicates that the atoms or molecules are in the lattice sites. But in the second case there is certainly no such ordering, and such a substance is more like a liquid.

Physics and the possible structure of a solid

In this case, the substance tends to maintain its volume and, of course, shape. That is, in order to change the latter, it is necessary to make efforts, and it does not matter whether it is a metal object, a piece of plastic or plasticine. The reason lies in its molecular structure. And more precisely, in the interaction of molecules, of which the body consists. In this case they are located most closely. This arrangement of molecules is of a recurring nature. That is why the forces of mutual attraction between each of these components are very large.

Interaction of microparticles explains the nature of their movement. The shape or volume of such a solid body is difficult to correct in one direction or another. Particles of a solid body are unable to move randomly throughout the volume of a solid, but can only oscillate near a certain point in space. The molecules of the solid fluctuate chaotically in different directions, but they come across similar ones, which return them to their original state. That is why particles in solids are located, as a rule, in a strictly defined order.

Particles and their location in a solid

Solid bodies can be of three types: crystalline, amorphous and composites. It is the chemical composition that affects the arrangement of particles in solids.

Crystalline solids have an ordered structure. Their molecules or atoms form a crystalline spatial lattice of regular shape. Thus, a solid body in a crystalline state has a definite crystal lattice, which in turn defines certain physical properties. This is the answer to how the particles are arranged in a solid.

Let us give an example: many years ago in St. Petersburg a stock of white shiny tin buttons was stored in the warehouse, which, when the temperature was lowered, lost their luster and turned from white to gray. The buttons were scattered in a gray powder. "Tin plague" - the so-called "disease", but in fact it was a restructuring of the crystal structure under the influence of low temperature. Tin during the transition from the white variety to the gray crumbles into powder. Crystals, in turn, are divided into mono- and polycrystals.

Single crystals and polycrystals

Monocrystals (table salt) are single homogeneous crystals represented by a continuous crystal lattice in the form of regular polygons. Polycrystals (sand, sugar, metals, stones) are crystalline bodies that have grown from small, chaotically arranged crystals. In crystals, a phenomenon such as anisotropy is observed.

Amorphous: a special case

Amorphous bodies (resin, rosin, glass, amber) do not have a strict strict order in the arrangement of the particles. This is a non-standard case of the order in which the particles are in solids. In this case, the phenomenon of isotropy is observed, the physical properties of amorphous bodies are the same in all directions. At high temperatures, they become similar to viscous liquids, and at low temperatures they are similar to solids. When exposed to external effects, they simultaneously exhibit elastic properties, that is, they break apart into miniature particles like solid bodies, and fluidity: they start flowing as liquids under prolonged temperature effects. They do not have definite melting and crystallization temperatures. When heated, amorphous bodies soften.

Examples of amorphous substances

Take, for example, ordinary sugar and find out the arrangement of particles in solids in various cases on its example. In this case, the same material can occur in crystalline or amorphous form. If the molten sugar freezes slowly, the molecules form even rows - crystals (lump sugar, or granulated sugar). If molten sugar, for example, pour into cold water, cooling will occur very quickly, and the particles do not have time to form the correct rows - the melt will harden without forming crystals. So it turns out sugar candy (this is non-crystalline sugar).

But after a while such a substance can recrystallize, the particles are collected in the right rows. If the sugar candy will lie down for several months, it will begin to become covered with a loose layer. So appear on the surface of the crystals. For sugar, the period will be several months, and for the stone - millions of years. A unique example is carbon. Graphite is a crystalline carbon, its structure is layered. A diamond is the hardest mineral on earth, capable of cutting glass and sawing stones, it is used for drilling and polishing. In this case the substance is one - carbon, but the feature is the ability to form different crystalline forms. This is another answer to how the particles are arranged in a solid.

Results. Conclusion

The structure and arrangement of particles in solids depends on the kind of substance to which the substance belongs. If the substance is crystalline, the arrangement of microparticles will be ordered. Amorphous structures do not possess such a feature. But composites can belong to both the first and the second group.

In one case, the fluid behaves like a solid (at a low temperature, which is close to the crystallization temperature), but it can also act as a gas (as it rises). Therefore, in this review material, we examined how particles are located not only in solids, but also in other basic aggregate states of matter.

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