In chemistry , an amphoteric compound (from Greek amphoteros 'both') is a molecule or ion that can react both as an acid and as a base . What exactly this can mean depends on which definitions of acids and bases are being used.
14-516: IPG may refer to: Immobilized pH gradient , a method used in isoelectric focusing Impedance phlebography , a medical test Implanted pulse generator ( neurostimulator ), a battery-powered device designed to deliver electrical stimulation to the brain Independent Publishers Group , a book distributor Interactive program guide, another name for an electronic program guide ,
28-580: A base. According to the Brønsted-Lowry theory of acids and bases , acids are proton donors and bases are proton acceptors. An amphiprotic molecule (or ion) can either donate or accept a proton , thus acting either as an acid or a base . Water , amino acids , hydrogencarbonate ion (or bicarbonate ion) HCO − 3 , dihydrogen phosphate ion H 2 PO − 4 , and hydrogensulfate ion (or bisulfate ion) HSO − 4 are common examples of amphiprotic species. Since they can donate
42-630: A base. The bicarbonate ion, HCO − 3 , is amphoteric as it can act as either an acid or a base: Note: in dilute aqueous solution the formation of the hydronium ion , H 3 O (aq) , is effectively complete, so that hydration of the proton can be ignored in relation to the equilibria. Other examples of inorganic polyprotic acids include anions of sulfuric acid , phosphoric acid and hydrogen sulfide that have lost one or more protons. In organic chemistry and biochemistry, important examples include amino acids and derivatives of citric acid . Although an amphiprotic species must be amphoteric,
56-465: A basic group −NH 2 and an acidic group −COOH , and exists as several structures in chemical equilibrium : In approximately neutral aqueous solution (pH ≅ 7), the basic amino group is mostly protonated and the carboxylic acid is mostly deprotonated, so that the predominant species is the zwitterion H 3 N −RCH−COO . The pH at which the average charge is zero is known as the molecule's isoelectric point . Ampholytes are used to establish
70-439: A graphical user interface for cable TV boxes, satellite TV boxes, VCRs, DVRs and televisions which displays programming information Internet Press Guild an invitation-only group of journalists, editors and industry analysts Interpacket gap (interframe gap), a networking term describing a part of total latency on a link The Interpublic Group of Companies , a marketing and communications group Intertape Polymer Group ,
84-539: A packaging products manufacturer IPG Photonics , a fiber laser manufacturer iPod games file extension Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title IPG . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=IPG&oldid=1190010107 " Category : Disambiguation pages Hidden categories: Short description
98-466: A proton, all amphiprotic substances contain a hydrogen atom. Also, since they can act like an acid or a base, they are amphoteric. The water molecule is amphoteric in aqueous solution. It can either gain a proton to form a hydronium ion H 3 O , or else lose a proton to form a hydroxide ion OH . Another possibility is the molecular autoionization reaction between two water molecules, in which one water molecule acts as an acid and another as
112-413: A stable pH gradient for use in isoelectric focusing . Metal oxides which react with both acids as well as bases to produce salts and water are known as amphoteric oxides. Many metals (such as zinc , tin , lead , aluminium , and beryllium ) form amphoteric oxides or hydroxides. Aluminium oxide ( Al 2 O 3 ) is an example of an amphoteric oxide. Amphoterism depends on the oxidation states of
126-411: Is different from Wikidata All article disambiguation pages All disambiguation pages Immobilized pH gradient Within chemistry for acid–base reactions , Immobilized pH gradient ( IPG ) gels are the acrylamide gel matrix co-polymerized with the pH gradient, which result in completely stable gradients except the most alkaline (>12) pH values. The immobilized pH gradient
140-401: Is obtained by the continuous change in the ratio of Immobilines . An Immobiline is a weak acid or base defined by its pK value. Immobilized pH gradients (IPG) are made by mixing two kinds of acrylamide mixture, one with Immobiline having acidic buffering property and other with basic buffering property. The concentrations of the buffers in the two solutions define the range and shape of
154-1115: The converse is not true. For example, a metal oxide such as zinc oxide , ZnO, contains no hydrogen and so cannot donate a proton. Nevertheless, it can act as an acid by reacting with the hydroxide ion, a base: This reaction is not covered by the Brønsted–Lowry acid–base theory . Because zinc oxide can also act as a base: it is classified as amphoteric rather than amphiprotic. Zinc oxide (ZnO) reacts with both acids and with bases: This reactivity can be used to separate different cations , for instance zinc(II), which dissolves in base, from manganese(II), which does not dissolve in base. Lead oxide (PbO): Lead oxide ( PbO 2 ): Aluminium oxide ( Al 2 O 3 ): Stannous oxide (SnO): Stannic oxide ( SnO 2 ): Vanadium dioxide ( VO 2 ): Some other elements which form amphoteric oxides are gallium , indium , scandium , titanium , zirconium , chromium , iron , cobalt , copper , silver , gold , germanium , antimony , bismuth , beryllium , and tellurium . Aluminium hydroxide
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#1732776042037168-455: The oxide. Amphoteric oxides include lead(II) oxide and zinc oxide , among many others. Amphoteric is derived from the Greek word amphoteroi ( ἀμφότεροι ) meaning "both". Related words in acid-base chemistry are amphichromatic and amphichroic , both describing substances such as acid-base indicators which give one colour on reaction with an acid and another colour on reaction with
182-742: The pH gradient produced. Both solutions contain acrylamide monomers and catalysts. During polymerization, the acrylamide portion of the buffers co polymerize with the acrylamide and bisacrylamide monomers to form a polyacrylamide gel. These polymerised gels are backed with plastic based backing that allow ease in handling and improve IPG's performance. The gel is then washed to remove catalysts and unpolymerized monomers , which interfere with isoelectric separation. IPG increased reproducibility of isoelectric focusing and 2D- gel electrophoresis . Other advantages are increased resolution, reproducible separation of alkaline proteins and increased loading capacity (up to 10 mg). This alternative method eliminates
196-740: The problems of gradient instability and poor sample loading capacity associated with carrier ampholyte pH gradient. Commercial precast IPG gels are available. Ampholyte One type of amphoteric species are amphiprotic molecules, which can either donate or accept a proton ( H ). This is what "amphoteric" means in Brønsted–Lowry acid–base theory . For example, amino acids and proteins are amphiprotic molecules because of their amine ( −NH 2 ) and carboxylic acid ( −COOH ) groups. Self-ionizable compounds like water are also amphiprotic. Ampholytes are amphoteric molecules that contain both acidic and basic functional groups . For example, an amino acid H 2 N−RCH−CO 2 H has both
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