Questions about what the state of aggregation, what features and properties are solids, liquids and gases are covered in several courses.There are three classical states of matter, with their characteristic structural features.Their understanding is an important point in understanding the earth sciences, living organisms, production activities.These questions are studying physics, chemistry, geography, geology, physical chemistry and other scientific disciplines.Substances that are under certain conditions in one of the three basic types of state may be changed by increasing or decreasing temperature, pressure.Consider the possible transitions from one state to another as they occur in nature, art and everyday life.
What is the physical state?
word of Latin origin "aggrego" in translation into Russian means "to join."The scientific term refers to the state of the same body, substance.The existence under certain temperature and different pressure values of solids, gases and liquids typical for all layers of the Earth.In addition to the three basic states of aggregation, there is also a fourth.At elevated temperature and constant pressure gas is converted into plasma.To better understand what the state of aggregation, it is necessary to recall the tiny particles that make up matter and the body.
The diagram above shows a - gas;b - liquid;C - solid.On these figures are indicated by circles structural elements of substance.This symbol is actually atoms, molecules, ions are not continuous beads.Atoms consist of a positively charged nucleus, around which move at high speed negatively charged electrons.Knowledge of the microscopic structure of matter helps to better understand the differences that exist between different aggregate forms.
representations about a microcosm, from ancient Greece to the XVII century
first information about the particles, which are composed of the physical body, appeared in ancient Greece.Thinkers Democritus and Epicurus introduced the notion of the atom.They believed that the smallest indivisible particles of different substances have a form of defined dimensions, able to move and interact with each other.Atomism was the most advanced for its time, the teaching of ancient Greece.But its development is stalled in the Middle Ages.Since then scientists pursued the Inquisition of the Roman Catholic Church.Therefore, until the new time there was no clear-cut concept of what the state of matter.Only after the XVII century scientists Robert Boyle, M. Lomonosov, D. Dalton, Lavoisier formulated the atomic-molecular theory, have not lost their importance today.
atoms, molecules, ions - microscopic particles of matter structure
significant breakthrough in understanding the microcosm occurred in the XX century, when it was invented by an electron microscope.In view of the discoveries made by scientists before, managed to lay down a coherent picture of the microworld.Theories that describe the state and behavior of the smallest particles of matter, it is difficult, they belong to the field of quantum physics.To understand the features of the different aggregate states of matter enough to know the name and the main structural features of particles that form a different substance.
- atoms - chemically indivisible particles.Stored in chemical reactions, but are destroyed in nuclear.Metals and many other substances the atomic structure are solid aggregate state under normal conditions.
- molecules - particles which are formed and destroyed in chemical reactions.Molecular structure are oxygen, water, carbon dioxide, sulfur.Physical state of oxygen, nitrogen, sulfur dioxide, carbon, oxygen, under normal conditions - gaseous.
- ions - charged particles, which are converted into atoms and molecules when attached or lose electrons - negatively charged microscopic particles.Ionic structure have a lot of salt, such as sodium, iron and copper sulfate.
There are substances which the particles are arranged in a certain way in space.Ordered relative position of atoms, ions, molecules called lattice.Typically, ionic and atomic lattices characteristic of solids, molecular - for liquids and gases.High hardness of diamond is different.His atomic crystal lattice is formed by carbon atoms.But the soft graphite also consists of atoms of a chemical element.Once they are arranged differently in space.Average sulfur aggregate state - solid, but at high temperatures, matter is converted into a liquid and amorphous mass.
substances in the solid state
solid under normal conditions, keep the volume and shape.Such as grain, grain of sugar, salt, a piece of rock or metal.If you heat the sugar, the substance begins to melt, turning into a viscous brown liquid.Stop heating - again to give a solid.So, one of the main conditions for the transition of a rigid body in a fluid - heating it or increase the internal energy of the particles of matter.Solid state salt, which is used in the food, too, can change.But to melt sodium chloride, need a higher temperature than when heated sugar.The fact that the sugar consists of molecules, and salt - of charged ions which are strongly attracted to each other.The solids in the liquid form does not maintain its shape because crystal lattices are destroyed.
liquid state by melting salt is due to rupture of communication between the ions in the crystals.Exempt charged particles that can carry electrical charges.Molten salts conduct electricity, are agents.The chemical, steel and engineering industry converted to solids to obtain a liquid of these novel compounds or impart different shapes.There was widespread metal alloys.There are several ways of getting involved with the changes the state of aggregation of the solid material.
liquid - one of the basic aggregate states
If you pour a round bottom flask 50 ml of water, we can see that the substance will soon form a chemical vessel.But as soon as we Spill water from the flask, the liquid immediately be spread on the surface of the table.The volume of water will remain the same - 50 ml, and its shape to change.These features are characteristic of the liquid form of existence of matter.Liquids are many organic substances: alcohols, vegetable oils, acids.
Milk - emulsion, ie. E. Liquid, which contains fat droplets.Useful liquid fossil - oil.Extract it from the wells with oil rigs on land and in the ocean.Sea water is also a raw material for industry.It differs from the fresh water lakes and rivers is dissolved materials, mainly salts.In the evaporation of surface water bodies in the vapor state transferred only H2O molecules dissolved substances remain.This property based methods for producing useful substances from the sea water and the method of cleaning.
When complete removal of salts using distilled water.It boils at 100 ° C, it freezes at 0 ° C.Pickles boil and turn into ice at other temperature indicators.For example, water in the Arctic Ocean freezes at a surface temperature of 2 ° C.
Appearance mercury under normal conditions - fluid.This silver-gray metal is usually filled with medical thermometer.When heated, the mercury rises on the scale, there is an expansion agent.Why in outdoor thermometers used red paint tinted alcohol, not mercury?This is due to the properties of the liquid metal.When the 30-degree cold aggregate state changes of mercury, a substance becomes solid.
If medical thermometer broke and the mercury poured out, then collect the silver balls hands is dangerous.Harmful inhaled mercury vapor, it is a very toxic substance.Children in such cases it is necessary to seek help from parents, adults.
gaseous state
Gaza are not able to maintain its volume of any or form.Fill the flask with oxygen up to the top (its chemical formula O2).As soon as we open the flask, molecules of the substance will be mixed with the air in the room.This is due to Brownian motion.The ancient Greek scholar Democritus believed that the particles of matter are in constant motion.In solids under normal conditions, atoms, molecules, ions, there is no possibility to leave the crystal lattice, free from ties with other particles.This is possible only when the large amount of energy from the outside.
In liquids the distance between the particles is slightly larger than in solids, they require less energy to break the intermolecular bonds.For example, the liquid aggregate state of oxygen is observed only when the temperature of gas to -183 ° C.At -223 ° C O2 molecule to form a solid.When the temperature rises above the given values of the oxygen is converted into a gas.In this form it is under normal conditions.Industrial enterprises are special plants for the separation of air from the atmosphere and produce a nitrogen and oxygen.First, the air is cooled and liquefied, and then gradually increase the temperature.Nitrogen and oxygen are converted into gases at different conditions.
Earth's atmosphere contains 21% by volume of oxygen and 78% nitrogen.The liquid form of these substances in the gas envelope planet not occur.Liquid oxygen has a light-blue color, it is filled with high pressure cylinders for use in medical facilities.In the construction industry and liquefied gases are required for so many processes.Oxygen is needed for gas welding and cutting metals, in chemistry - for the oxidation of inorganic and organic substances.If you open the valve on the oxygen cylinder pressure is reduced, the liquid turns into a gas.
Liquefied propane, methane and butane are widely used in energy, transport, industry and domestic activities of the population.These substances obtained from natural gas or by cracking (cleavage) of the petroleum feedstock.Carbon liquid and gaseous mixture are important in many economies.But the reserves of oil and natural gas greatly depleted.According to scientists, this raw material will last for 100-120 years.An alternative energy source - the air flow (wind).Used for power plants fast flowing rivers, tides on the shores of the seas and oceans.
Oxygen, as well as other gases may be present in the fourth aggregate state, representing the plasma.Unusual transition from solid to gaseous state - a characteristic feature of crystalline iodine.The substance is a deep purple color is exposed to sublimation - turns to gas, bypassing the liquid state.
How are transitions from one aggregate to another form of matter?
changes physical state of matter not related to chemical transformations, this physical phenomenon.At higher temperatures, many solids melt liquefies.Further increase in temperature can lead to evaporation, ie to the gaseous state of matter.The nature and the economy, such transitions are characteristic of one of the main substances in the world.Ice, liquid, vapor, - a state of water in different environments.Compound same, formula - H2O.At 0 ° C, and below this water crystallizes, that is transformed to ice.When the temperature rises caused crystals are destroyed - the ice melts, it turns liquid water again.While heating steam is formed.Evaporation - conversion of water gas - is even at low temperatures.For example, frozen puddles gradually disappear because the water evaporates.Even in cold weather dries wet clothes, but the process is longer than that on a hot day.
All of the water transfer from one state to another are essential to the nature of the Earth.Atmospheric phenomena, the climate and the weather associated with the evaporation of water from the ocean surface, the transfer of moisture in the form of clouds and fog in the land, precipitation (rain, snow, hail).These phenomena are the basis of the world's water cycle.
How to change the state of aggregation of sulfur?
Under ordinary conditions of sulfur - a bright shiny crystals or light yellow powder, m. E. The solid.Physical state sulfur changes when heated.First, when the temperature rises to 190 ° C yellow solid melts, becoming a mobile liquid.If
quickly pour liquid sulfur into the cold water, it turns brown amorphous mass.With further heating the molten sulfur it becomes more viscous, dark.At temperatures above 300 ° C sulfur aggregate state changes again, the material becomes fluid properties, becomes mobile.These transitions are due to the ability of atoms of an element forming a chain of different lengths.Why
matter can be in different physical states?
Appearance sulfur - a simple matter - solid under normal conditions.Sulphur dioxide - the gas, sulfuric acid - oily liquid is heavier than water.Unlike hydrochloric and nitric acids, it is not volatile, its surface molecules vaporize.What is the state of aggregation of a plastic sulfur, which is obtained by heating the crystals?
The amorphous form has a structure of the liquid substance, having low fluidity.But plastic sulfur at the same time retains its shape (as solid).There are liquid crystals, which have a number of characteristic properties of solids.Thus, the state of the substance under different conditions depends on its nature, the temperature, pressure and other environmental conditions.
What are the features in the structure of solids?
The differences between the main aggregate states of matter are explained by the interaction between atoms, ions and molecules.For example, why solid state of matter results in the ability to maintain body size and shape?In the crystal lattice of a metal salt or structural particles are attracted to each other.In metals, positively charged ions interact with the so-called "electron gas" - the accumulation of free electrons in a metal bar.The crystals of salt are due to the attraction of oppositely charged particles - ions.The distance between the structural units of the above solids is much less than the dimensions of the particles themselves.In this case, the electrostatic attraction, it gives strength and repulsion is not strong enough.
to destroy the solid state of matter, we must make the effort.Metal salts, the atomic crystals melt at very high temperatures.For example, iron becomes liquid at temperatures above 1538 ° C.Refractory is tungsten, of it made filament for electric bulbs.There are alloys that become liquid at temperatures above 3000 ° C.Many rocks and minerals on Earth are in a solid state.This raw material is produced using technology in mines and quarries.
for separation even one ion from the crystal need to expend a lot of energy.But it is enough to dissolve the salt in the water to the crystal lattice broke!This phenomenon is explained by the amazing properties of water as a polar solvent.H2O molecules interact with ions of salt, breaking a chemical bond between them.Thus, the dissolution - is not simple mixing of different substances, and physico-chemical interaction between them.
As liquid molecules interact?
Water may be liquid, solid and gas (steam).This is its main aggregate state under normal conditions.The water molecules are composed of one oxygen atom, which is associated with two hydrogen atoms.There is a polarization of chemical bonds in the molecule, the atoms of oxygen appears a partial negative charge.Hydrogen becomes positive pole molecule is attracted by an oxygen atom of another molecule.It is the weak interaction has been called "the hydrogen bond".
liquid state is characterized by the distance between the structural particles, comparable with their size.
