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Avogadro's Law
Avogadro's law (sometimes referred to as Avogadro's hypothesis or Avogadro's principle) or Avogadro-Ampère's hypothesis is an experimental gas law relating the volume of a gas to the amount of substance of gas present. The law is a specific case of the ideal gas law. A modern statement is: Avogadro's law states that "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules." For a given mass of an ideal gas, the volume and amount (moles) of the gas are directly proportional if the temperature and pressure are constant. The law is named after Amedeo Avogadro who, in 1812, hypothesized that two given samples of an ideal gas, of the same volume and at the same temperature and pressure, contain the same number of molecules. As an example, equal volumes of gaseous hydrogen and nitrogen contain the same number of molecules when they are at the same temperature and pressure, and display ideal gas behavior. In practice, real gases show sm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Laws
The laws describing the behaviour of gases under fixed pressure, volume, amount of gas, and absolute temperature conditions are called gas laws. The basic gas laws were discovered by the end of the 18th century when scientists found out that relationships between pressure, volume and temperature of a sample of gas could be obtained which would hold to approximation for all gases. The combination of several empirical gas laws led to the development of the ideal gas law. The ideal gas law was later found to be consistent with atomic and kinetic theory. History In 1643, the Italian physicist and mathematician, Evangelista Torricelli, who for a few months had acted as Galileo Galilei's secretary, conducted a celebrated experiment in Florence. He demonstrated that a column of mercury in an inverted tube can be supported by the pressure of air outside of the tube, with the creation of a small section of vacuum above the mercury. This experiment essentially paved the way towards ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specific Volume
In thermodynamics, the specific volume of a substance (symbol: , nu) is the quotient of the substance's volume () to its mass (): :\nu = \frac It is a mass-specific intrinsic property of the substance. It is the reciprocal of density (rho) and it is also related to the molar volume and molar mass: :\nu = \rho^ = \frac The standard unit of specific volume is cubic meters per kilogram (m3/kg), but other units include ft3/lb, ft3/slug, or mL/g. Specific volume for an ideal gas is related to the molar gas constant () and the gas's temperature (), pressure (), and molar mass (): : \nu = \frac It's based on the ideal gas law, PV = , and the amount of substance In chemistry, the amount of substance (symbol ) in a given sample of matter is defined as a ratio () between the particle number, number of elementary entities () and the Avogadro constant (). The unit of amount of substance in the International ..., n = m/M Applications Specific volume is commonly applied to: * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joseph Louis Gay-Lussac
Joseph Louis Gay-Lussac ( , ; ; 6 December 1778 – 9 May 1850) was a French chemist and physicist. He is known mostly for his discovery that water is made of two parts hydrogen and one part oxygen by volume (with Alexander von Humboldt), for two laws related to gases, and for his work on alcohol–water mixtures, which led to the degrees Gay-Lussac used to measure alcoholic beverages in many countries. Biography Gay-Lussac was born at Saint-Léonard-de-Noblat in the present-day department of Haute-Vienne. His father, Anthony Gay, son of a doctor, was a lawyer and prosecutor and worked as a judge in Noblat Bridge. Father of two sons and three daughters, he owned much of the Lussac village and began to add the name of this hamlet to his name, following a custom of the Ancien Régime. Towards the year 1803, father and son formally adopted the name Gay-Lussac. During the Revolution, under the Law of Suspects, his father, former king's attorney, was imprisoned in Saint L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dalton Atomic Theory
John Dalton (; 5 or 6 September 1766 – 27 July 1844) was an English chemist, physicist and meteorologist. He introduced the atomic theory into chemistry. He also researched colour blindness; as a result, the umbrella term for red-green congenital colour blindness disorders is ''Daltonism'' in several languages. Early life John Dalton was born on 5 or 6 September 1766 into a Quaker family in Eaglesfield, near Cockermouth, in Cumberland, England. His father was a weaver. He received his early education from his father and from Quaker John Fletcher, who ran a private school in the nearby village of Pardshaw Hall. Dalton's family was too poor to support him for long and he began to earn his living, from the age of ten, in the service of wealthy local Quaker Elihu Robinson. Early career When he was 15, Dalton joined his older brother Jonathan in running a Quaker school in Kendal, Westmorland, about from his home. Around the age of 23, Dalton may have considered stu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gay-Lussac's Law
Gay-Lussac's law usually refers to Joseph-Louis Gay-Lussac's law of combining volumes of gases, discovered in 1808 and published in 1809. However, it sometimes refers to the proportionality of the volume of a gas to its Thermodynamic temperature, absolute temperature at constant pressure. The latter law was published by Gay-Lussac in 1802, but in the article in which he described his work, he cited earlier unpublished work from the 1780s by Jacques Charles. Consequently, the volume-temperature proportionality is usually known as ''Charles's law''. Law of combining volumes The law of combining volumes states that when gases chemically react together, they do so in amounts by volume which bear small whole-number ratios (the volumes calculated at the same temperature and pressure). The ratio between the volumes of the reactant gases and the gaseous products can be expressed in simple Natural number, whole numbers. For example, Gay-Lussac found that two volumes of hydrogen react ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles's Law
Charles's law (also known as the law of volumes) is an experimental gas law that describes how gases tend to expand when heated. A modern statement of Charles's law is: When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be in direct proportion. This relationship of direct proportion can be written as: :V \propto T So this means: :\frac = k, \quad \text \quad V=k T where: * is the volume of the gas, * is the temperature of the gas (measured in kelvins), and * is a constant for a particular pressure and amount of gas. This law describes how a gas expands as the temperature increases; conversely, a decrease in temperature will lead to a decrease in volume. For comparing the same substance under two different sets of conditions, the law can be written as: \frac=\frac The equation shows that, as absolute temperature increases, the volume of the gas also increases in proportion. History The law was named after scien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boyle's Law
Boyle's law, also referred to as the Boyle–Mariotte law or Mariotte's law (especially in France), is an empirical gas laws, gas law that describes the relationship between pressure and volume of a confined gas. Boyle's law has been stated as: The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of substance, amount of gas remain unchanged within a closed system.Levine (1978) p. 12 gives the original definition. Mathematically, Boyle's law can be stated as: or where is the pressure of the gas, is the volume of the gas, and is a Constant (mathematics), constant for a particular temperature and amount of gas. Boyle's law states that when the temperature of a given mass of confined gas is constant, the product of its pressure and volume is also constant. When comparing the same substance under two different sets of conditions, the law can be expressed as: P_1 V_1 = P_2 V_2. showi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loschmidt Constant
The Loschmidt constant or Loschmidt's number (symbol: ''n''0) is the number of particles (atoms or molecules) of an ideal gas per volume (the number density), and usually quoted at standard temperature and pressure. The 2018 CODATA recommended value is at 0 °C and 1 atm. It is named after the Austrian physicist Johann Josef Loschmidt, who was the first to estimate the physical size of molecules in 1865. The term Loschmidt constant is also sometimes used to refer to the Avogadro constant, particularly in German texts. By ideal gas law, p_0V = Nk_\textT_0, and since N = n_0 V, the Loschmidt constant is given by the relationship : n_0 = \frac, where ''k''B is the Boltzmann constant, ''p''0 is the standard pressure, and ''T''0 is the standard thermodynamic temperature. Since the Avogadro constant ''N''A satisfies R = N_\text k, the Loschmidt constant satisfies : n_0 = \frac, where ''R'' is the ideal gas constant. Being a measure of number density, the Loschmidt const ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Conditions For Temperature And Pressure
Standard temperature and pressure (STP) or standard conditions for temperature and pressure are various standard sets of conditions for experimental measurements used to allow comparisons to be made between different sets of data. The most used standards are those of the International Union of Pure and Applied Chemistry (IUPAC) and the National Institute of Standards and Technology (NIST), although these are not universally accepted. Other organizations have established a variety of other definitions. In industry and commerce, the standard conditions for temperature and pressure are often necessary for expressing the volumes of gases and liquids and related quantities such as the rate of volumetric flow (the volumes of gases vary significantly with temperature and pressure): standard cubic meters per second (Sm3/s), and normal cubic meters per second (Nm3/s). Many technical publications (books, journals, advertisements for equipment and machinery) simply state "standard cond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avogadro Constant
The Avogadro constant, commonly denoted or , is an SI defining constant with an exact value of when expressed in reciprocal moles. It defines the ratio of the number of constituent particles to the amount of substance in a sample, where the particles in question are any designated elementary entity, such as molecules, atoms, ions, ion pairs. The numerical value of this constant is known as the Avogadro number, commonly denoted . The Avogadro ''number'' is an exact number equal to the number of constituent particles in one mole of any substance (by definition of the mole), historically derived from the experimental determination of the number of atoms in 12 grams of carbon-12 (12C) before the 2019 revision of the SI. Both the constant and the number are named after the Italian physicist and chemist Amedeo Avogadro. The Avogadro constant is used as a proportionality factor in relating the ''amount of substance'' , in a sample of a substance , to the corresponding n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boltzmann Constant
The Boltzmann constant ( or ) is the proportionality factor that relates the average relative thermal energy of particles in a ideal gas, gas with the thermodynamic temperature of the gas. It occurs in the definitions of the kelvin (K) and the molar gas constant, in Planck's law of black-body radiation and Boltzmann's entropy formula, and is used in calculating Johnson–Nyquist noise, thermal noise in resistors. The Boltzmann constant has Dimensional analysis, dimensions of energy divided by temperature, the same as entropy and heat capacity. It is named after the Austrian scientist Ludwig Boltzmann. As part of the 2019 revision of the SI, the Boltzmann constant is one of the seven "Physical constant, defining constants" that have been defined so as to have exact finite decimal values in SI units. They are used in various combinations to define the seven SI base units. The Boltzmann constant is defined to be exactly joules per kelvin, with the effect of defining the SI unit ke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pascal (unit)
The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI). It is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is an SI coherent derived unit defined as one newton per square metre (N/m2). It is also equivalent to 10 barye (10 Ba) in the CGS system. Common multiple units of the pascal are the hectopascal (1 hPa = 100 Pa), which is equal to one millibar, and the kilopascal (1 kPa = 1000 Pa), which is equal to one centibar. The unit of measurement called '' standard atmosphere (atm)'' is defined as . Meteorological observations typically report atmospheric pressure in hectopascals per the recommendation of the World Meteorological Organization, thus a standard atmosphere (atm) or typical sea-level air pressure is about 1013 hPa. Reports in the United States typically use inches of mercury or millibars (hectopascals). In Cana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
