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Universal Indicator
__FORCETOC__ A universal indicator is a pH indicator made of a solution of several compounds that exhibits several smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. Although there are several commercially available universal pH indicators, most are a variation of a formula patented by Yamada in 1933. Details of this patent can be found in ''Chemical Abstracts''. Experiments with Yamada's universal indicator are also described in the ''Journal of Chemical Education''. A universal indicator is usually composed of water, 1-propanol, phenolphthalein, sodium hydroxide, methyl red, bromothymol blue, sodium bisulfite, and thymol blue. The colours that indicate the pH of a solution, after adding a universal indicator, are The colours from yellow to red indicate an acidic solution, colours blue to violet indicate an alkaline solution and a green colour indicates that a solution is neutral. Wide-range pH test papers with distinc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universal Indicator Paper
Universal is the adjective for universe. Universal may also refer to: Companies * NBCUniversal, a media and entertainment company ** Universal Animation Studios, an American Animation studio, and a subsidiary of NBCUniversal ** Universal TV, a television channel owned by NBCUniversal ** Universal Kids, an American current television channel, formerly known as Sprout, owned by NBCUniversal ** Universal Pictures, an American film studio, and a subsidiary of NBCUniversal ** Universal Television, a television division owned by NBCUniversal Content Studios ** Universal Parks & Resorts, the theme park unit of NBCUniversal * Universal Airlines (other) * Universal Avionics, a manufacturer of flight control components * Universal Corporation, an American tobacco company * Universal Display Corporation, a manufacturer of displays * Universal Edition, a classical music publishing firm, founded in Vienna in 1901 * Universal Entertainment Corporation, a Japanese software producer and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Bisulfite
Sodium bisulfite (or sodium bisulphite, sodium hydrogen sulfite) is a chemical mixture with the approximate chemical formula NaHSO3. Sodium bisulfite in fact is not a real compound, but a mixture of salts that dissolve in water to give solutions composed of sodium and bisulfite ions. It appears in form of white or yellowish-white crystals with an odor of sulfur dioxide. For properties of sodium bisulfite, refer to the table located to the right. Regardless of its ill-defined nature, sodium bisulfite is used in many different industries such a food additive with E number E222 in the food industry, a reducing agent in the cosmetic industry, and a decomposer of residual hypochlorite used in the bleaching industry. Synthesis Sodium bisulfite solutions can be prepared by treating a solution of suitable base, such as sodium hydroxide or sodium bicarbonate with sulfur dioxide. :SO2 + NaOH → NaHSO3 :SO2 + NaHCO3 → NaHSO3 + CO2 Attempts to crystallize the product yield So ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acidity Or Alkalinity
A pH indicator is a halochromic chemical compound added in small amounts to a solution so the pH ( acidity or basicity) of the solution can be determined visually or spectroscopically by changes in absorption and/or emission properties. Hence, a pH indicator is a chemical detector for hydronium ions (H3O+) or hydrogen ions (H+) in the Arrhenius model. Normally, the indicator causes the color of the solution to change depending on the pH. Indicators can also show change in other physical properties; for example, olfactory indicators show change in their odor. The pH value of a neutral solution is 7.0 at 25°C ( standard laboratory conditions). Solutions with a pH value below 7.0 are considered acidic and solutions with pH value above 7.0 are basic. Since most naturally occurring organic compounds are weak electrolytes, such as carboxylic acids and amines, pH indicators find many applications in biology and analytical chemistry. Moreover, pH indicators form one of the three m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proton
A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ratio). Protons and neutrons, each with masses of approximately one atomic mass unit, are jointly referred to as " nucleons" (particles present in atomic nuclei). One or more protons are present in the nucleus of every atom. They provide the attractive electrostatic central force which binds the atomic electrons. The number of protons in the nucleus is the defining property of an element, and is referred to as the atomic number (represented by the symbol ''Z''). Since each element has a unique number of protons, each element has its own unique atomic number, which determines the number of atomic electrons and consequently the chemical characteristics of the element. The word ''proton'' is Greek for "first", and this name was given to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenolphthalein
Phenolphthalein ( ) is a chemical compound with the formula C20 H14 O4 and is often written as "HIn", "HPh", "phph" or simply "Ph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions. It belongs to the class of dyes known as phthalein dyes. Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols for use in experiments. It is a weak acid, which can lose H+ ions in solution. The nonionized phenolphthalein molecule is colorless and the double deprotonated phenolphthalein ion is fuchsia. Further loss of proton in higher pH occurs slowly and leads to a colorless form. Phenolphthalein ion in concentrated sulfuric acid is orange red due to sulfonation. Uses pH indicator Phenolphthalein's common use is as an indicator in acid-base titrations. It also serves as a component of universal indicator, together with methyl red ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromothymol Blue
Bromothymol blue (also known as bromothymol sulfone phthalein and BTB) is a pH indicator. It is mostly used in applications that require measuring substances that would have a relatively neutral pH (near 7). A common use is for measuring the presence of carbonic acid in a liquid. It is typically sold in solid form as the sodium salt of the acid indicator. Structure and properties Bromothymol blue acts as a weak acid in a solution. It can thus be in protonated or deprotonated form, appearing yellow or blue, respectively. It is bright aquamarine by itself, and greenish-blue in a neutral solution. The deprotonation of the neutral form results in a highly conjugated structure, accounting for the difference in color. An intermediate of the deprotonation mechanism is responsible for the greenish color in neutral solution. The protonated form of bromothymol blue has its peak absorption at 427 nm thus transmitting yellow light in acidic solutions, and the deprotonated form has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Red
Methyl red (2-(''N'',''N''-dimethyl-4-aminophenyl) azobenzenecarboxylic acid), also called C.I. Acid Red 2, is an indicator dye that turns red in acidic solutions. It is an azo dye, and is a dark red crystalline powder. Methyl red is a pH indicator; it is red in pH under 4.4, yellow in pH over 6.2, and orange in between, with a p''K''a of 5.1. Murexide and methyl red are investigated as promising enhancers of sonochemical destruction of chlorinated hydrocarbon pollutants. Methyl red is classed by the IARC in group 3 - unclassified as to carcinogenic potential in humans. Preparation As an azo dye, methyl red may be prepared by diazotization of anthranilic acid, followed by reaction with dimethylaniline: : Properties Methyl red displays pH dependent photochromism, with protonation causing it to adopt a hydrazone/quinone structure. : Methyl Red has a special use in histopathology for showing acidic nature of tissue and presence of organisms with acidic natured cell walls. Met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Orange
Methyl orange is a pH indicator frequently used in titration because of its clear and distinct color variance at different pH values. Methyl orange shows red color in acidic medium and yellow color in basic medium. Because it changes color at the p''K''a of a mid strength acid, it is usually used in titration of strong acids in weak bases that reach the equivalence point at a pH of 3.1-4.4. Unlike a universal indicator, methyl orange does not have a full spectrum of color change, but it has a sharp end point. In a solution becoming less acidic, methyl orange changes from red to orange and, finally, to yellow—with the reverse process occurring in a solution of increasing acidity. Indicator colors In a solution that decreases in acidity, methyl orange moves from the color red to orange and finally to yellow with the opposite occurring for a solution increasing in acidity. This color change from yellow to red occurs because the protons in the acidic solution react with the N=N b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymol Blue
Thymol blue (thymolsulfonephthalein) is a brownish-green or reddish-brown crystalline powder that is used as a pH indicator. It is insoluble in water but soluble in alcohol and dilute alkali solutions. It transitions from red to yellow at pH 1.2–2.8 and from yellow to blue at pH 8.0–9.6. It is usually a component of Universal indicator __FORCETOC__ A universal indicator is a pH indicator made of a solution of several compounds that exhibits several smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. Although there are several .... At wavelength (378 - 382) nm, extinction coefficient > 8000 and at wavelength (298 - 302) nm , the extinction coefficient > 12000. Structures Thymol blue has different structures at different pH. :thymol blue. Safety It may cause irritation. Its toxicological properties have not been fully investigated. Harmful if swallowed, Acute Toxicity. Only Hazardous when percent values are above ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymol Blue
Thymol blue (thymolsulfonephthalein) is a brownish-green or reddish-brown crystalline powder that is used as a pH indicator. It is insoluble in water but soluble in alcohol and dilute alkali solutions. It transitions from red to yellow at pH 1.2–2.8 and from yellow to blue at pH 8.0–9.6. It is usually a component of Universal indicator __FORCETOC__ A universal indicator is a pH indicator made of a solution of several compounds that exhibits several smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. Although there are several .... At wavelength (378 - 382) nm, extinction coefficient > 8000 and at wavelength (298 - 302) nm , the extinction coefficient > 12000. Structures Thymol blue has different structures at different pH. :thymol blue. Safety It may cause irritation. Its toxicological properties have not been fully investigated. Harmful if swallowed, Acute Toxicity. Only Hazardous when percent values are above ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromothymol Blue
Bromothymol blue (also known as bromothymol sulfone phthalein and BTB) is a pH indicator. It is mostly used in applications that require measuring substances that would have a relatively neutral pH (near 7). A common use is for measuring the presence of carbonic acid in a liquid. It is typically sold in solid form as the sodium salt of the acid indicator. Structure and properties Bromothymol blue acts as a weak acid in a solution. It can thus be in protonated or deprotonated form, appearing yellow or blue, respectively. It is bright aquamarine by itself, and greenish-blue in a neutral solution. The deprotonation of the neutral form results in a highly conjugated structure, accounting for the difference in color. An intermediate of the deprotonation mechanism is responsible for the greenish color in neutral solution. The protonated form of bromothymol blue has its peak absorption at 427 nm thus transmitting yellow light in acidic solutions, and the deprotonated form has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skala Boja 2
Skala may refer to: Places Greece * Skala, Patmos, the main port on the island of Patmos in Greece * Skala, Laconia, a municipality in southern Greece * Skala, Xanthi, a settlement in north-eastern Greece * Skala, Cephalonia, a resort in the Ionian Islands Elsewhere * Skała (other), several places in Poland * Skala-Podilska, a town in Ukraine * Skala, Burgas Province, a village in Burgas Province, south-eastern Bulgaria * , a village in Dulovo Municipality, Silistra Province, north-eastern Bulgaria * Skála, a village in the Faroe Islands * Skåla (other), places in Norway Other uses * SKALA, the process computer for the Chernobyl-type nuclear power plants * Skala (sports organization), a Jewish Communist sports organization in interbellum Poland * ''Skala'', a 2011 album by Mathias Eick * Zastava Skala, a subcompact car made by Serbian manufacturer Zastava See also * Scala (other) Scala or SCALA may refer to: Automobiles * Renault Sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
