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Nei diagrammi che riportano la temperatura in ordinata ad esempio un digramma composizione-temperatura o entalpia-temperatura le conodali sono rappresentate da segmenti orizzontali i cui estremi si trovano sulle curve di equilibrio del sistema in esame.
Diagramma di fase — For the use of this term in mathematics and physics, see phase space. Common components of a phase diagram are lines of equilibrium or phase boundaries, phase transitions occur along lines of equilibrium. Triple points are points on phase diagrams where lines of equilibrium intersect, triple points mark conditions at which three different phases can coexist.
For example, the phase diagram has a triple point corresponding to the linea solidus liquidus pump temperature and pressure at which solid, liquid. The solidus is the temperature below which the substance is stable in the solid state, the liquidus is the temperature above which the substance is stable in a liquid state. There may be a gap between the solidus and liquidus, within the gap, the substance consists of a mixture of crystals, the simplest phase diagrams are pressure—temperature diagrams of a single simple substance, such as water.
The axes correspond to the pressure and temperature, the phase diagram shows, in pressure—temperature space, the lines of equilibrium or phase boundaries between the three phases of solid, liquid, and gas. The fusion curves for water and Antimony are with negative slopes, the curves on the phase diagram show the points where the free energy becomes linea solidus liquidus pump, their derivatives with respect to the coordinates change linea solidus liquidus pump.
For example, the capacity of a container filled with ice will change abruptly as the container is heated past the melting point. The open spaces, where the energy is analytic, correspond to single phase regions. Single phase regions are separated by lines of non-analytical behavior, where phase transitions occur, in the diagram on the left, the phase boundary between liquid and gas does not continue indefinitely. Instead, it terminates at a point on the diagram called the critical point.
This reflects the fact that, at high temperatures and pressures. Thus, the liquid and gaseous phases can blend continuously into each other, the solid—liquid phase boundary can only end in a critical point if the solid and liquid phases have the same symmetry group. Thus, the substance requires a temperature for its molecules to have enough energy to break out of the fixed pattern of the solid phase. A similar concept applies to liquid—gas phase changes, water, because of its particular properties, is one of the several exceptions to the rule.
In addition to temperature and pressure, other properties may be graphed in phase diagrams. Termodinamica — Thermodynamics is a branch of science concerned with heat and temperature and their relation to energy and work. The behavior of these quantities is governed by the four laws of thermodynamics, the laws of thermodynamics are explained in terms of microscopic constituents by statistical mechanics.
Thermodynamics applies to a variety of topics in science and engineering, especially physical chemistry, chemical engineering. The initial application of thermodynamics to mechanical heat engines was extended early on to the study of chemical compounds, Chemical thermodynamics studies the nature of the role of entropy in the process of chemical reactions and has provided the bulk of expansion and knowledge of the field.
Other formulations of thermodynamics emerged in the following decades, statistical thermodynamics, or statistical mechanics, concerned itself with statistical predictions of the collective motion of particles from their microscopic behavior.
A description of any thermodynamic linea solidus liquidus pump employs the four laws of thermodynamics that form an axiomatic basis, the first law specifies that energy can be exchanged between physical systems as heat and work. In thermodynamics, interactions between large ensembles of objects are studied and categorized, central to this are the concepts of the thermodynamic system and its surroundings. A system is composed linea solidus liquidus pump particles, whose average motions define its properties, properties can be combined to express internal energy and thermodynamic potentials, which are useful for determining conditions for equilibrium and spontaneous processes.
With these tools, thermodynamics linea solidus liquidus pump be used to describe how systems respond to changes in linea solidus liquidus pump environment and this can be applied to a wide variety of topics in science and engineering, such as engines, phase transitions, chemical reactions, transport phenomena, and even black holes.
This article is focused mainly on classical thermodynamics which primarily studies systems in thermodynamic equilibrium, non-equilibrium thermodynamics is often treated as an extension of the classical treatment, but statistical mechanics has brought many advances to that field.
Guericke was driven to make a linea solidus liquidus pump in order to disprove Aristotles long-held supposition that nature abhors a vacuum. Shortly after Guericke, the English physicist and chemist Robert Boyle had learned of Guerickes linea solidus liquidus pump and, inin coordination with English scientist Robert Hooke, using this pump, Boyle and Hooke noticed a correlation between pressure, temperature, and volume.
In time, Boyles Law was formulated, which states that pressure, later designs implemented a steam release valve that kept the machine from exploding. By watching the valve rhythmically move up and down, Papin conceived of the idea of a piston and he did not, however, follow through with his design. Nevertheless, inbased on Papins designs, engineer Thomas Savery built the first engine, although these early engines were crude and inefficient, they attracted the attention of the leading scientists of the time.
Black and Watt performed experiments together, but it was Watt who conceived the idea of the condenser which resulted in a large increase in steam engine efficiency.
Drawing on all the work led Sadi Carnot, the father of thermodynamics, to publish Reflections on the Motive Power of Fire. In contrast, a process is where a system exchanges no heat with its surroundings. Isothermal processes can occur in any kind of system that has some means of regulating the temperature, including highly structured machines, some parts of the cycles of some heat engines are carried out isothermally.
In the thermodynamic analysis of reactions, it is usual to first analyze what happens under isothermal conditions. Phase changes, linea solidus liquidus pump as melting or evaporation, are also isothermal processes when, as is usually the case, isothermal processes are often used and a starting point in analyzing more complex, non-isothermal processes. Isothermal processes are of special interest for ideal gases and this is a consequence of Joules second law which states that the internal energy of a fixed amount of an ideal gas depends only on its temperature.
Thus, in a process the internal energy of an ideal gas is constant. This is a result of the fact that in a gas there are no intermolecular forces. Note that this is only for ideal gases, the internal energy depends on pressure as well as on temperature for liquids, solids.
In the isothermal compression of a gas there is work is done on the system to decrease the volume, doing work on the gas increases the internal energy and will tend to increase the temperature. To maintain the constant temperature energy must leave the system as heat, if the gas is ideal, the amount of energy entering the environment is equal to the work done on the gas, because internal energy does not change. If there is no work done, i. For an ideal gas, this means that the process is also isothermal, thus, specifying that a process is isothermal is not sufficient to specify a unique process.
For the special case of a gas to which Boyles law applies, the value of the constant is nRT, where n is the number of moles of gas present and R is the ideal gas constant. Temperatura — A temperature is an objective comparative measurement of hot or cold. It is measured by a thermometer, several scales and units exist for measuring temperature, the most common being Celsius, Fahrenheit, and, especially in science, Kelvin.
Temperature is important in all fields of science including physics, geology, chemistry, atmospheric sciences, medicine. The Celsius scale is used for temperature measurements in most of the world. Because of the degree interval, it is called a centigrade scale. Many scientific measurements use the Kelvin temperature scale, named in honor of the Scottish physicist who first defined it and it is a thermodynamic or absolute temperature scale.
Its zero point, 0K, is defined to coincide with the coldest physically-possible temperature and its degrees are defined through thermodynamics. For historical reasons, the triple point temperature of water is fixed at There is a variety of kinds of temperature scale and it may be convenient to classify them as empirically and theoretically based.
Empirical temperature scales are historically older, while theoretically based scales arose in the middle of the nineteenth century, empirically based temperature scales rely directly on measurements of simple physical properties of materials. For example, the length of a column of mercury, confined in a capillary tube, is dependent largely on temperature. Such scales are only within convenient ranges of temperature. For example, above the point of mercury, a mercury-in-glass thermometer is impracticable.
A material is of no use as a thermometer near one of its phase-change temperatures, in spite of linea solidus liquidus pump restrictions, most generally used practical thermometers are of the empirically based kind.
Especially, it was used for calorimetry, which contributed greatly to the discovery of thermodynamics, nevertheless, empirical thermometry has serious drawbacks when judged as a basis for theoretical physics. Theoretically based temperature scales are based directly on theoretical arguments, especially those of thermodynamics, kinetic theory and they rely on theoretical linea solidus liquidus pump of idealized devices and materials. Gas — Linea solidus liquidus pump is one of the four fundamental states linea solidus liquidus pump matter.
A pure gas may be made up of atoms, elemental molecules made from one type of atom. A linea solidus liquidus pump mixture would contain a variety of pure gases much like the air, what distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colorless gas invisible to the human observer, the interaction of gas particles in the presence of electric and gravitational fields are considered negligible as indicated by the constant velocity vectors in the image.
One linea solidus liquidus pump of commonly known gas is steam, the gaseous state of matter is found between the liquid and plasma states, the latter of which provides the upper temperature boundary for linea solidus liquidus pump. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention, high-density atomic gases super cooled to incredibly low temperatures are classified by their statistical behavior as either a Bose gas or a Fermi gas.
For a comprehensive listing of these states of matter see list of states of matter. The only chemical elements which are stable multi atom homonuclear molecules at temperature and pressure, are hydrogen, nitrogen and oxygen.
These gases, when grouped together with the noble gases. Alternatively they are known as molecular gases to distinguish them from molecules that are also chemical compounds. The word gas is a neologism first used by the early 17th-century Flemish chemist J.
An alternative story is that Van Helmonts word is corrupted from gahst and these four characteristics were repeatedly observed by scientists such as Linea solidus liquidus pump Boyle, Jacques Charles, John Dalton, Joseph Gay-Lussac and Amedeo Avogadro for a variety of gases in various settings. Their detailed studies ultimately led to a relationship among these properties expressed by the ideal gas law. Gas particles are separated from one another, and consequently have weaker intermolecular bonds than liquids or solids.
These intermolecular forces result from interactions between gas particles. Like-charged areas of different linea solidus liquidus pump particles repel, while oppositely charged regions of different gas particles attract linea solidus liquidus pump another, transient, randomly induced charges exist across non-polar covalent bonds of molecules and electrostatic interactions caused by them are referred to as Van der Waals forces.
The interaction of these forces varies within a substance which determines many of the physical properties unique to each gas. A comparison of boiling points for compounds formed by ionic and covalent bonds leads us to this conclusion, the drifting smoke particles in the image provides some insight into low pressure gas behavior. Liquido — A liquid is a nearly incompressible fluid that conforms to the shape of linea solidus liquidus pump container but retains a constant volume independent of pressure.
As such, it linea solidus liquidus pump one of the four states of matter. A liquid is made up of tiny vibrating particles of matter, such as atoms, water is, by far, the most common liquid on Earth.
Like a gas, a liquid is able to flow and take the shape of a container, most liquids resist compression, although others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, a distinctive property of the liquid state is surface tension, leading to wetting phenomena.
The density of a liquid is usually close to linea solidus liquidus pump of a solid, therefore, liquid and solid are both termed condensed matter.
Most known matter in the universe is in form as interstellar clouds or in plasma form within stars. Liquid is one of the four states of matter, with the others being solid, gas. Unlike a linea solidus liquidus pump, the molecules in a liquid have a greater freedom to move. The forces that bind the molecules together in a solid are only temporary in a liquid, a liquid, like a gas, displays the properties of a fluid. A liquid can flow, assume the shape of a container, if liquid is placed in a bag, it can be squeezed into any shape.
These properties make a suitable for applications such as hydraulics. Liquid particles are bound linea solidus liquidus pump but not rigidly and they are able to move around one another freely, resulting in a limited degree of particle mobility. As the temperature increases, the vibrations of the molecules causes distances between the molecules to increase.
When a liquid reaches its point, the cohesive forces that bind the molecules closely together break. If the temperature is decreased, the distances between the molecules become smaller, only two elements are liquid at standard conditions for temperature and pressure, mercury and bromine.
Four more elements have melting points slightly above room temperature, francium, caesium, gallium and rubidium, metal alloys that are liquid at room temperature include NaK, a sodium-potassium metal alloy, galinstan, a fusible alloy liquid, and some amalgams.