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Potassium Hydrogen Phthalate
Potassium hydrogen phthalate, often called simply KHP, is an acidic salt compound. It forms white powder, colorless crystals, a colorless solution, and an ionic solid that is the monopotassium salt of phthalic acid. KHP is slightly acidic, and it is often used as a primary standard for acid–base titrations because it is solid and air-stable, making it easy to weigh accurately. It is not hygroscopic. It is also used as a primary standard for calibrating pH meters because, besides the properties just mentioned, its pH in solution is very stable. It also serves as a thermal standard in thermogravimetric analysis. KHP dissociates completely in water, giving the potassium cation (K+) and hydrogen phthalate anion (HP− or Hphthalate−) : KHP -> atop\ce/chem> K+ + HP− and then, acting as a weak acid, hydrogen phthalate reacts reversibly with water to give hydronium (H3O+) and phthalate ions. : HP− + H2O P2− + H3O+ KHP can be used as a buffering agent in combination wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid
Solid is a state of matter where molecules are closely packed and can not slide past each other. Solids resist compression, expansion, or external forces that would alter its shape, with the degree to which they are resisted dependent upon the specific material under consideration. Solids also always possess the least amount of kinetic energy per atom/molecule relative to other phases or, equivalently stated, solids are formed when matter in the liquid / gas phase is cooled below a certain temperature. This temperature is called the melting point of that substance and is an intrinsic property, i.e. independent of how much of the matter there is. All matter in solids can be arranged on a microscopic scale under certain conditions. Solids are characterized by structural rigidity and resistance to applied external forces and pressure. Unlike liquids, solids do not flow to take on the shape of their container, nor do they expand to fill the entire available volume like a gas. Much ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydronium
In chemistry, hydronium (hydroxonium in traditional British English) is the cation , also written as , the type of oxonium ion produced by protonation of water. It is often viewed as the positive ion present when an Arrhenius acid is dissolved in water, as Arrhenius acid molecules in solution give up a proton (a positive hydrogen ion, ) to the surrounding water molecules (). In fact, acids must be surrounded by more than a single water molecule in order to ionize, yielding aqueous and conjugate base. Three main structures for the aqueous proton have garnered experimental support: * the Eigen cation, which is a tetrahydrate, H3O+(H2O)3 * the Zundel cation, which is a symmetric dihydrate, H+(H2O)2 * and the Stoyanov cation, an expanded Zundel cation, which is a hexahydrate: H+(H2O)2(H2O)4 Spectroscopic evidence from well-defined IR spectra overwhelmingly supports the Stoyanov cation as the predominant form. For this reason, it has been suggested that wherever possible, the sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxylic Acids
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an Substituent, R-group. The general formula of a carboxylic acid is often written as or , sometimes as with R referring to an organyl group (e.g., alkyl, alkenyl, aryl), or hydrogen, or other groups. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion. Examples and nomenclature Carboxylic acids are commonly identified by their trivial names. They often have the suffix ''-ic acid''. IUPAC-recommended names also exist; in this system, carboxylic acids have an ''-oic acid'' suffix. For example, butyric acid () is butanoic acid by IUPAC guidelines. For nomenclature of complex molecules containing a carboxylic acid, the carboxyl can be considered position one of the parent chain even if there are other substituents, such as 3-chloropropanoic acid. Alternately, it can be named ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,4-Benzoquinone
1,4-Benzoquinone, commonly known as ''para''-quinone, is a chemical compound with the chemical formula, formula C6H4O2. In a pure state, it forms bright-yellow crystals with a characteristic irritating odor, resembling that of chlorine, bleach, and hot plastic or formaldehyde. This six-membered ring compound is the oxidized derivative of 1,4-hydroquinone. The molecule is multifunctional: it exhibits properties of a ketone, being able to form oximes; an oxidant, forming the dihydroxy derivative; and an alkene, undergoing addition reactions, especially those typical for α,β-unsaturated carbonyl compound, α,β-unsaturated ketones. 1,4-Benzoquinone is sensitive toward both strong mineral acids and alkali, which cause condensation and decomposition of the compound. Preparation 1,4-Benzoquinone is prepared industrially by oxidation of hydroquinone, which can be obtained by several routes. One route involves oxidation of Diisopropylbenzenes, diisopropylbenzene and the Hock rearrangem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Organic Carbon
Total organic carbon (TOC) is an analytical parameter representing the concentration of organic carbon in a sample. TOC determinations are made in a variety of application areas. For example, TOC may be used as a non-specific indicator of water quality, or TOC of source rock may be used as one factor in evaluating a petroleum play. For marine surface sediments average TOC content is 0.5% in the deep ocean, and 2% along the eastern margins. A typical analysis for total carbon (TC) measures both the total organic carbon (TOC) present and the complementing total inorganic carbon (TIC), the latter representing the amount of non-organic carbon, like carbon in carbonate minerals. Subtracting the inorganic carbon from the total carbon yields TOC. Another common variant of TOC analysis involves removing the TIC portion first and then measuring the leftover carbon. This method involves purging an acidified sample with carbon-free air or nitrogen prior to measurement, and so is mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Hydroxide
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), base and alkali that decomposes lipids and proteins at ambient temperatures and at high concentrations may cause severe chemical burns. It is highly soluble in water, and readily absorbs moisture and carbon dioxide from the air. It forms a series of hydrates . The monohydrate crystallizes from water solutions between 12.3 and 61.8 °C. The commercially available "sodium hydroxide" is often this monohydrate, and published data may refer to it instead of the anhydrous compound. As one of the simplest hydroxides, sodium hydroxide is frequently used alongside neutral water and acidic hydrochloric acid to demonstrate the pH scale to chemistry students. Sodium hydroxide is used in many industries: in the making of wood pulp and paper, tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrochloric Acid
Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is a component of the gastric acid in the digestive systems of most animal species, including humans. Hydrochloric acid is an important laboratory reagent and industrial chemical. Etymology Because it was produced from halite, rock salt according to the methods of Johann Rudolph Glauber, hydrochloric acid was historically called by European alchemists ''spirits of salt'' or ''acidum salis'' (salt acid). Both names are still used, especially in other languages, such as , , , , , , , , , , (''ensan''), zh, 盐酸 (''yánsuān''), and (''yeomsan''). Gaseous HCl was called ''marine acid air''. The name ''muriatic acid'' has the same origin (''muriatic'' means "pertaining to brine or salt", hence ''muriate'' means hydrochloride), and this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buffering Agent
A buffer solution is a solution where the pH does not change significantly on dilution or if an acid or base is added at constant temperature. Its pH changes very little when a small amount of strong acid or base is added to it. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. In nature, there are many living systems that use buffering for pH regulation. For example, the bicarbonate buffering system is used to regulate the pH of blood, and bicarbonate also acts as a buffer in the ocean. Principles of buffering Buffer solutions resist pH change because of a chemical equilibrium between the weak acid HA and its conjugate base A−: When some strong acid is added to an equilibrium mixture of the weak acid and its conjugate base, hydrogen ions (H+) are added, and the equilibrium is shifted to the left, in accordance with Le Chatelier's principle. Because of this, the hydrogen ion concentration increas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weak Acid
Acid strength is the tendency of an acid, symbolised by the chemical formula , to dissociate into a proton, , and an anion, . The dissociation or ionization of a strong acid in solution is effectively complete, except in its most concentrated solutions. : Examples of strong acids are hydrochloric acid (), perchloric acid (), nitric acid () and sulfuric acid (). A weak acid is only partially dissociated, or is partly ionized in water with both the undissociated acid and its dissociation products being present, in solution, in equilibrium with each other. : Acetic acid () is an example of a weak acid. The strength of a weak acid is quantified by its acid dissociation constant, K_a value. The strength of a weak organic acid may depend on substituent effects. The strength of an inorganic acid is dependent on the oxidation state for the atom to which the proton may be attached. Acid strength is solvent-dependent. For example, hydrogen chloride is a strong acid in aqueous solu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium
Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, which is easily removed to create cation, an ion with a positive charge (which combines with anions to form salts). In nature, potassium occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-flame color, colored flame. It is found dissolved in seawater (which is 0.04% potassium by weight), and occurs in many minerals such as orthoclase, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermogravimetric Analysis
Thermogravimetric analysis or thermal gravimetric analysis (TGA) is a method of thermal analysis in which the mass of a sample is measured over time as the temperature changes. This measurement provides information about physical phenomena, such as phase transitions, absorption, adsorption and desorption; as well as chemical phenomena including chemisorptions, thermal decomposition, and solid-gas reactions (e.g., oxidation or reduction). Thermogravimetric analyzer Thermogravimetric analysis (TGA) is conducted on an instrument referred to as a thermogravimetric analyzer. A thermogravimetric analyzer continuously measures mass while the temperature of a sample is changed over time. Mass, temperature, and time are considered base measurements in thermogravimetric analysis while many additional measures may be derived from these three base measurements. A typical thermogravimetric analyzer consists of a precision balance with a sample pan located inside a furnace with a programm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PH Meter
A pH meter is a scientific instrument that measures the hydrogen-ion activity in water-based solutions, indicating its acidity or alkalinity expressed as pH. The pH meter measures the difference in electrical potential between a pH electrode and a reference electrode, and so the pH meter is sometimes referred to as a "potentiometric pH meter". The difference in electrical potential relates to the acidity or pH of the solution. Testing of pH via pH meters (pH-metry) is used in many applications ranging from laboratory experimentation to quality control. Applications The rate and outcome of chemical reactions taking place in water often depends on the acidity of the water, and it is therefore useful to know the acidity of the water, typically measured by means of a pH meter. Knowledge of pH is useful or critical in many situations, including chemical laboratory analyses. pH meters are used for soil measurements in agriculture, water quality for municipal water supplies, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
