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Ebullioscope
An ebullioscope (from the Latin ''ēbullīre'' (to boil) + -scope) is an instrument for measuring the boiling point of a liquid. This can be used for determining the alcoholic strength of a mixture, or for determining the molecular weight of a non-volatile solute based on the boiling-point elevation Boiling-point elevation describes the phenomenon that the boiling point of a liquid (a solvent) will be higher when another compound is added, meaning that a solution has a higher boiling point than a pure solvent. This happens whenever a non-vo .... The procedure is known as ebullioscopy. The first ebullioscope was invented in 1838 by Honoré Brossard-Vidal, and was used for measuring alcoholic content. The advantage of this method was that the boiling point is relatively insensitive to other components such as sugars. Older alcoholimeters were based on measuring the density, which is more sensitive to the presence of other solutes. A famous ebullioscope variant was built by Pierre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ebullioscope
An ebullioscope (from the Latin ''ēbullīre'' (to boil) + -scope) is an instrument for measuring the boiling point of a liquid. This can be used for determining the alcoholic strength of a mixture, or for determining the molecular weight of a non-volatile solute based on the boiling-point elevation Boiling-point elevation describes the phenomenon that the boiling point of a liquid (a solvent) will be higher when another compound is added, meaning that a solution has a higher boiling point than a pure solvent. This happens whenever a non-vo .... The procedure is known as ebullioscopy. The first ebullioscope was invented in 1838 by Honoré Brossard-Vidal, and was used for measuring alcoholic content. The advantage of this method was that the boiling point is relatively insensitive to other components such as sugars. Older alcoholimeters were based on measuring the density, which is more sensitive to the presence of other solutes. A famous ebullioscope variant was built by Pierre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ebullioscopic Constant
In thermodynamics, the ebullioscopic constant relates molality to boiling point elevation. It is the ratio of the latter to the former: :\Delta T = iK_\text b * is the van 't Hoff factor, the number of particles the solute splits into or forms when dissolved. * is the molality of the solution. A formula to compute the ebullioscopic constant is: :K_\text = \frac * is the ideal gas constant. * is boiling point of the solvent. * is the molar mass of the solvent. * is the molar enthalpy of vaporization. Through the procedure called ebullioscopy, a known constant can be used to calculate an unknown molar mass. The term ''ebullioscopy'' comes from the Latin language and means "boiling measurement". This is related to cryoscopy, which determines the same value from the cryoscopic constant (of freezing point depression). This property of elevation of boiling point is a colligative property. It means that the property, in this case , depends on the number of particles dissolved int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boiling Point
The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding environmental pressure. A liquid in a partial vacuum has a lower boiling point than when that liquid is at atmospheric pressure. A liquid at low pressure has a lower boiling point than when that liquid is at atmospheric pressure. Because of this, water boils at under standard pressure at sea level, but at at altitude. For a given pressure, different liquids will boiling, boil at different temperatures. The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, one Atmosphere (unit), atmosphere. At that temperature, the vapor pressure of the liquid becomes suffici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boiling-point Elevation
Boiling-point elevation describes the phenomenon that the boiling point of a liquid (a solvent) will be higher when another compound is added, meaning that a solution has a higher boiling point than a pure solvent. This happens whenever a non-volatile solute, such as a salt, is added to a pure solvent, such as water. The boiling point can be measured accurately using an ebullioscope. Explanation The ''boiling point elevation'' is a colligative property, which means that it is dependent on the presence of dissolved particles and their number, but not their identity. It is an effect of the dilution of the solvent in the presence of a solute. It is a phenomenon that happens for all solutes in all solutions, even in ideal solutions, and does not depend on any specific solute–solvent interactions. The boiling point elevation happens both when the solute is an electrolyte, such as various salts, and a nonelectrolyte. In thermodynamic terms, the origin of the boiling point elevation is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcoholimeter
A hydrometer or lactometer is an instrument used for measuring density or relative density of liquids based on the concept of buoyancy. They are typically calibrated and graduated with one or more scales such as specific gravity. A hydrometer usually consists of a sealed hollow glass tube with a wider bottom portion for buoyancy, a ballast such as lead or mercury for stability, and a narrow stem with graduations for measuring. The liquid to test is poured into a tall container, often a graduated cylinder, and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer correlates to relative density. Hydrometers can contain any number of scales along the stem corresponding to properties correlating to the density. Hydrometers are calibrated for different uses, such as a lactometer for measuring the density (creaminess) of milk, a saccharometer for measuring the density of sugar in a liqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
François-Marie Raoult
François-Marie Raoult (; 10 May 1830 – 1 April 1901) was a French chemist who conducted research into the behavior of solutions, especially their physical properties. Life and work Raoult was born at Fournes, in the ''département'' of Nord. He became aspirant ''répétiteur'' at the Lycée of Reims in 1853, and after holding several intermediate positions was appointed in 1862 to the professorship of chemistry in Sens lycée. There he prepared a thesis on electromotive force which gained him a doctor's degree in Paris the following year. In 1867 Raoult was put in charge of chemistry classes at the University of Grenoble, and three years later he succeeded to the chair of chemistry, which he held until his death in 1901. Raoult's earliest researches were physical in character, being largely concerned with the phenomena of the voltaic cell; later there was a period when more purely chemical questions engaged his attention. Raoult's name is best known in connection with wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beckmann Thermometer
A Beckmann thermometer is a device used to measure small differences of temperature, but not absolute temperature values. It was invented by Ernst Otto Beckmann (1853 – 1923), a German chemist, for his measurements of colligative properties in 1905. Today its use has largely been superseded by electronic thermometers. A Beckmann thermometer's length is usually 40 – 50 cm. The temperature scale typically covers about 5 °C and it is divided into hundredths of a degree. With a magnifier it is possible to estimate temperature changes to 0.001 °C. The peculiarity of Beckmann's thermometer design is a reservoir (R on diagram) at the upper end of the tube, by means of which the quantity of mercury in the bulb can be increased or diminished so that the instrument can be set to measure temperature differences at either high or low temperature values. In contrast, the range of a typical mercury-in-glass thermometer is fixed, being set by the calibration mark ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Otto Beckmann
Ernst Otto Beckmann (July 4, 1853 – July 12, 1923) was a German pharmacist and chemist who is remembered for his invention of the Beckmann differential thermometer and for his discovery of the Beckmann rearrangement. Scientific work Ernst Otto Beckmann was born in Solingen, Germany on July 4, 1853, to a family headed by Johannes Friedrich Wilhelm Beckmann, a manufacturer. The elder Beckmann's factory produced mineral dyes, pigments, abrasives, and polishing material, and it was there that the younger Beckmann conducted his early chemical experiments. At the age of 17, Beckmann was persuaded by his father to study pharmacy instead of chemistry, and so in 1870 an apprenticeship was arranged in Elberfeld. However, Beckmann did not enjoy the working conditions and returned home, to his father's disappointment. Told that a chemical career would be difficult if could not handle an apprenticeship in pharmacy, Beckmann then returned to Elberfeld to finish his work. He also worked at ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Weight
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and ''molecule'' is often used when referring to polyatomic ions. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term ''molecule'' is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are typically not consi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ebulliometer
An ebulliometer is designed to accurately measure the boiling point of liquids by measuring the temperature of the vapor–liquid equilibrium either isobarically or isothermally. The primary components in a Świętosławski ebulliometer, which operates isobarically, are the boiler, the Cottrell pumps, the thermowell, and the condenser. Such an ebulliometer can be used for extremely accurate measurements of boiling temperature, molecular weights, mutual solubilities, and solvent purities by using a resistance thermometer (RTD) to measure the near-equilibrium conditions of the thermowell. The ebulliometer is frequently used for measuring the alcohol content of dry wines. See also Sweetness of wine and Oechsle scale The Oechsle scale is a hydrometer scale measuring the density of grape must, which is an indication of grape ripeness and sugar content used in wine-making. It is named for Ferdinand Oechsle (1774–1852) and it is widely used in the German, Swiss .... References * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
