1.
Alkali metal
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The alkali metals are a group in the periodic table consisting of the chemical elements lithium, sodium, potassium, rubidium, caesium, and francium. Indeed, the alkali metals provide the best example of trends in properties in the periodic table. The alkali metals are all shiny, soft, highly reactive metals at standard temperature and pressure and they can all be cut easily with a knife due to their softness, exposing a shiny surface that tarnishes rapidly in air due to oxidation by atmospheric moisture and oxygen. Because of their reactivity, they must be stored under oil to prevent reaction with air. Caesium, the alkali metal, is the most reactive of all the metals. All the alkali metals react with water, with the alkali metals reacting more vigorously than the lighter ones. Experiments have been conducted to attempt the synthesis of ununennium, which is likely to be the member of the group. Most alkali metals have different applications. One of the applications of the pure elements is the use of rubidium and caesium in atomic clocks, of which caesium atomic clocks are the most accurate. A common application of the compounds of sodium is the sodium-vapour lamp, table salt, or sodium chloride, has been used since antiquity. The physical and chemical properties of the alkali metals can be explained by their having an ns1 valence electron configuration. Hence, all the metals are soft and have low densities, melting and boiling points, as well as heats of sublimation, vaporisation. They all crystallise in the cubic crystal structure, and have distinctive flame colours because their outer s electron is very easily excited. The ns1 configuration also results in the alkali metals having very large atomic and ionic radii, most of the chemistry has been observed only for the first five members of the group. The chemistry of francium is not well established due to its radioactivity, thus. What little is known about francium shows that it is close in behaviour to caesium. The physical properties of francium are even sketchier because the element has never been observed. The alkali metals are more similar to other than the elements in any other group are to each other
2.
Alkaline earth metal
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The alkaline earth metals are six chemical elements in column 2 of the Periodic table. They are beryllium, magnesium, calcium, strontium, barium, the elements have very similar properties, they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure. All the discovered alkaline earth metals occur in nature, experiments have been conducted to attempt the synthesis of element 120, the next potential member of the group, but they have all met with failure. The chemistry of radium is not well-established due to its radioactivity, thus, the alkaline earth metals are all silver-colored and soft, and have relatively low densities, melting points, and boiling points. In chemical terms, all of the alkaline metals react with the halogens to form the earth metal halides. All the alkaline earth metals except beryllium also react with water to form strongly alkaline hydroxides and, thus, the heavier alkaline earth metals react more vigorously than the lighter ones. The second ionization energy of all of the metals is also somewhat low. Beryllium is an exception, It does not react with water or steam, all compounds that include beryllium have a covalent bond. Even the compound beryllium fluoride, which is the most ionic beryllium compound, has a low melting point and a low electrical conductivity when melted. The alkaline earth metals all react with the halogens to form ionic halides, such as calcium chloride, calcium, strontium, and barium react with water to produce hydrogen gas and their respective hydroxides, and also undergo transmetalation reactions to exchange ligands. The table below is a summary of the key physical and atomic properties of the alkaline earth metals, calcium-48 is the lightest nuclide to undergo double beta decay. The natural radioisotope of calcium, calcium-48, makes up about 0. 1874% of natural calcium, barium-130 makes up approximately 0. 1062% of natural barium, and, thus, barium is weakly radioactive, as well. The alkaline earth metals are named after their oxides, the alkaline earths, whose old-fashioned names were beryllia, magnesia, lime, strontia and these oxides are basic when combined with water. Earth is an old term applied by early chemists to nonmetallic substances that are insoluble in water, the realization that these earths were not elements but compounds is attributed to the chemist Antoine Lavoisier. In his Traité Élémentaire de Chimie of 1789 he called them salt-forming earth elements, later, he suggested that the alkaline earths might be metal oxides, but admitted that this was mere conjecture. The calcium compounds calcite and lime have been known and used since prehistoric times, the same is true for the beryllium compounds beryl and emerald. The other compounds of the alkaline earth metals were discovered starting in the early 15th century, the magnesium compound magnesium sulfate was first discovered in 1618 by a farmer at Epsom in England. Strontium carbonate was discovered in minerals in the Scottish village of Strontian in 1790, the last element is the least abundant, radioactive radium, which was extracted from uraninite in 1898
3.
Nonmetal
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In chemistry, a nonmetal is a chemical element that mostly lacks metallic attributes. Seventeen elements are classified as nonmetals, most are gases, one is a liquid. Moving rightward across the standard form of the table, nonmetals adopt structures that have progressively fewer nearest neighbours. Polyatomic nonmetals have structures with either three nearest neighbours, as is the case with carbon, or two nearest neighbours in the case of sulfur, diatomic nonmetals, such as hydrogen, have one nearest neighbour, and the monatomic noble gases, such as helium, have none. This gradual fall in the number of nearest neighbours is associated with a reduction in metallic character, the distinction between the three categories of nonmetals, in terms of receding metallicity is not absolute. Boundary overlaps occur as outlying elements in each category show less-distinct, living organisms are also composed almost entirely of nonmetals, and nonmetals form many more compounds than metals. There is no definition of a nonmetal. They show more variability in their properties than metals do, the following are some of the chief characteristics of nonmetals. The elements generally classified as nonmetals include one element in group 1, one in group 14, the distinction between nonmetals and metals is by no means clear. Nonmetals have structures in each atom usually forms bonds with nearest neighbours. Each atom is able to complete its valence shell and attain a stable noble gas configuration. Exceptions to the rule occur with hydrogen, carbon, nitrogen and oxygen, atoms of the latter three elements are sufficiently small such that they are able to form alternative bonding structures, with fewer nearest neighbours. Thus, carbon is able to form its layered graphite structure, the larger size of the remaining non-noble nonmetals weakens their capacity to form multiple bonds and they instead form two or more single bonds to two or more different atoms. Sulfur, for example, forms an eight-membered molecule in which the atoms are arranged in a ring, a similar pattern occurs more generally, at the level of the entire periodic table, in comparing metals and nonmetals. There is a transition from metallic bonding among the metals on the left of the table through to covalent or Van der Waals bonding among the nonmetals on the right of the table, metallic bonding tends to involve close-packed centrosymmetric structures with a high number of nearest neighbours. Post-transition metals and metalloids, sandwiched between the metals and the nonmetals, tend to have more complex structures with an intermediate number of nearest neighbours. Nonmetallic bonding, towards the right of the table, features open-packed directional structures with fewer or zero nearest neighbours, as is the case with the major categories of metals, metalloids and nonmetals, there is some variation and overlapping of properties within and across each category of nonmetal. Among the polyatomic nonmetals, carbon, phosphorus and selenium—which border the metalloids—begin to show some metallic character, sulfur, is the least metallic of the polyatomic nonmetals but even here shows some discernible metal-like character
4.
Polymer
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A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Because of their range of properties, both synthetic and natural polymers play an essential and ubiquitous role in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure, Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. The units composing polymers derive, actually or conceptually, from molecules of low molecular mass. The term was coined in 1833 by Jöns Jacob Berzelius, though with a distinct from the modern IUPAC definition. The modern concept of polymers as covalently bonded macromolecular structures was proposed in 1920 by Hermann Staudinger, Polymers are studied in the fields of biophysics and macromolecular science, and polymer science. Polyisoprene of latex rubber is an example of a polymer. In biological contexts, essentially all biological macromolecules—i. e, proteins, nucleic acids, and polysaccharides—are purely polymeric, or are composed in large part of polymeric components—e. g. Isoprenylated/lipid-modified glycoproteins, where small molecules and oligosaccharide modifications occur on the polyamide backbone of the protein. The simplest theoretical models for polymers are ideal chains, Polymers are of two types, Natural polymeric materials such as shellac, amber, wool, silk and natural rubber have been used for centuries. A variety of natural polymers exist, such as cellulose. Most commonly, the continuously linked backbone of a used for the preparation of plastics consists mainly of carbon atoms. A simple example is polyethylene, whose repeating unit is based on ethylene monomer, however, other structures do exist, for example, elements such as silicon form familiar materials such as silicones, examples being Silly Putty and waterproof plumbing sealant. Oxygen is also present in polymer backbones, such as those of polyethylene glycol, polysaccharides. Polymerization is the process of combining many small molecules known as monomers into a covalently bonded chain or network, during the polymerization process, some chemical groups may be lost from each monomer. This is the case, for example, in the polymerization of PET polyester, the distinct piece of each monomer that is incorporated into the polymer is known as a repeat unit or monomer residue. Laboratory synthetic methods are divided into two categories, step-growth polymerization and chain-growth polymerization. However, some methods such as plasma polymerization do not fit neatly into either category
5.
Actinide
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The actinide /ˈæktᵻnaɪd/ or actinoid /ˈæktᵻnɔɪd/ series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The actinide series derives its name from the first element in the series, the informal chemical symbol An is used in general discussions of actinide chemistry to refer to any actinide. All but one of the actinides are f-block elements, corresponding to the filling of the 5f electron shell, lawrencium, in comparison with the lanthanides, also mostly f-block elements, the actinides show much more variable valence. They all have very large atomic and ionic radii and exhibit a large range of physical properties. While actinium and the late actinides behave similarly to the lanthanides, all actinides are radioactive and release energy upon radioactive decay, naturally occurring uranium and thorium, and synthetically produced plutonium are the most abundant actinides on Earth. These are used in nuclear reactors and nuclear weapons, uranium and thorium also have diverse current or historical uses, and americium is used in the ionization chambers of most modern smoke detectors. Of the actinides, primordial thorium and uranium occur naturally in substantial quantities, the radioactive decay of uranium produces transient amounts of actinium and protactinium, and atoms of neptunium and plutonium are occasionally produced from transmutation reactions in uranium ores. The other actinides are purely synthetic elements, like the lanthanides, the actinides form a family of elements with similar properties. Within the actinides, there are two overlapping groups, transuranium elements, which follow uranium in the periodic table—and transplutonium elements, compared to the lanthanides, which are found in nature in appreciable quantities, most actinides are rare. The most abundant, or easily synthesized actinides are uranium and thorium, the existence of transuranium elements was suggested by Enrico Fermi based on his experiments in 1934. However, even though four actinides were known by that time, synthesis of transuranics gradually undermined this point of view. By 1944 an observation that curium failed to exhibit oxidation states above 4 prompted Glenn Seaborg to formulate a so-called actinide hypothesis, at present, there are two major methods of producing isotopes of transplutonium elements, irradiation of the lighter elements with either neutrons or accelerated charged particles. The advantage of the method is that elements heavier than plutonium, as well as neutron-deficient isotopes, can be obtained. In 1962–1966, there were attempts in the United States to produce transplutonium isotopes using a series of six underground nuclear explosions and this inobservation was attributed to spontaneous fission owing to the large speed of the products and to other decay channels, such as neutron emission and nuclear fission. Uranium and thorium were the first actinides discovered, uranium was identified in 1789 by the German chemist Martin Heinrich Klaproth in pitchblende ore. He named it after the planet Uranus, which had been discovered eight years earlier. Klaproth was able to precipitate a yellow compound by dissolving pitchblende in nitric acid and he then reduced the obtained yellow powder with charcoal, and extracted a black substance that he mistook for metal. Only 60 years later, the French scientist Eugène-Melchior Péligot identified it with uranium oxide and he also isolated the first sample of uranium metal by heating uranium tetrachloride with potassium
6.
Dyeing
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Dyeing is the process of adding color to textile products like fibers, yarns, and fabrics. Dyeing is normally done in a solution containing dyes and particular chemical material. After dyeing, dye molecules have uncut chemical bond with fiber molecules, the temperature and time controlling are two key factors in dyeing. There are mainly two classes of dye, natural and man-made, the primary source of dye, historically, has generally been nature, with the dyes being extracted from animals or plants. Since the mid-19th century, however, humans have produced artificial dyes to achieve a range of colors and to render the dyes more stable to resist washing. Different classes of dyes are used for different types of fiber and at different stages of the production process, from loose fibers through yarn. Acrylic fibers are dyed with basic dyes, while nylon and protein fibers such as wool and silk are dyed with acid dyes, cotton is dyed with a range of dye types, including vat dyes, and modern synthetic reactive and direct dyes. The word dye is from Middle English deie and from Old English dag, the first known use of the word dye was before the 12th century. The earliest dyed flax fibers have found in a prehistoric cave in the Republic of Georgia. In China, dyeing with plants, barks, and insects has been traced more than 5,000 years. Early evidence of dyeing comes from Sindh province in Pakistan, where a piece of cotton dyed with a dye was recovered from the archaeological site at Mohenjo-daro. The dye used in case was madder, which, along with other dyes such as indigo, was introduced to other regions through trade. The first synthetic dye was William Perkins mauveine in 1856, derived from coal tar, alizarin, the red dye present in madder, was the first natural pigment to be duplicated synthetically in 1869, a development which led to the collapse of the market for naturally grown madder. The development of new, strongly colored synthetic dyes followed quickly, dyes are applied to textile goods by dyeing from dye solutions and by printing from dye pastes. Methods include direct application and yarn dyeing and this renders the dye soluble so that it can be absorbed by the fiber since the insoluble dye has very little substantivity to the fiber. Direct dyes, a class of dyes largely for dyeing cotton, are water-soluble, most other classes of synthetic dye, other than vat and surface dyes, are also applied in this way. The term may also be applied to dyeing without the use of mordants to fix the dye once it is applied, mordants were often required to alter the hue and intensity of natural dyes and improve color fastness. Chromium salts were until recently used in dyeing wool with synthetic mordant dyes
7.
Paint
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Paint is any liquid, liquefiable, or mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture to objects, Paint can be made or purchased in many colors—and in many different types, such as watercolor, synthetic, etc. Paint is typically stored, sold, and applied as a liquid, in 2001 and 2004, South African archeologists reported finds in Blombos Cave of a 100, 000-year-old human-made ochre-based mixture that could have been used like paint. Further excavation in the cave resulted in the 2011 report of a complete toolkit for grinding pigments. Cave paintings drawn with red or yellow ochre, hematite, manganese oxide, ancient colored walls at Dendera, Egypt, which were exposed for years to the elements, still possess their brilliant color, as vivid as when they were painted about 2,000 years ago. The Egyptians mixed their colors with a substance, and applied them separately from each other without any blending or mixture. They appear to have used six colors, white, black, blue, red, yellow and they first covered the area entirely with white, then traced the design in black, leaving out the lights of the ground color. They used minium for red, and generally of a dark tinge, pliny mentions some painted ceilings in his day in the town of Ardea, which had been done prior to the foundation of Rome. He expresses great surprise and admiration at their freshness, after the lapse of so many centuries, Paint was made with the yolk of eggs and therefore, the substance would harden and adhere to the surface it was applied to. Pigment was made from plants, sand, and different soils, Most paints used either oil or water as a base. The process was done by hand by the painters and exposed them to lead poisoning due to the white-lead powder, in 1718, Marshall Smith invented a Machine or Engine for the Grinding of Colours in England. It is not known precisely how it operated, but it was a device that increased the efficiency of pigment grinding dramatically. By the proper onset of the Industrial Revolution, paint was being ground in steam-powered mills, interior house painting increasingly became the norm as the 19th century progressed, both for decorative reasons and because the paint was effective in preventing the walls rotting from damp. Linseed oil was also used as an inexpensive binder. In 1866, Sherwin-Williams in the United States opened as a large paint-maker and it was not until the stimulus of World War II created a shortage of linseed oil in the supply market that artificial resins, or alkyds, were invented. Cheap and easy to make, they held the color well. The vehicle is composed of the binder, or, if it is necessary to thin the binder with a diluent like solvent or water, it is the combination of binder + diluent. In this case, once the paint has dried or cured very nearly all of the diluent has evaporated, thus, an important quantity in coatings formulation is the vehicle solids, sometimes called the resin solids of the formula
8.
Sodium acetate
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Sodium acetate, CH3COONa, also abbreviated NaOAc, also known as sodium ethanoate, is the sodium salt of acetic acid. This colorless deliquescent salt has a range of uses. Sodium acetate is used in the industry to neutralize sulfuric acid waste streams. It is also an agent in chrome tanning and helps to impede vulcanization of chloroprene in synthetic rubber production. In processing cotton for disposable cotton pads, sodium acetate is used to eliminate the buildup of static electricity. Sodium acetate may be added to food as a seasoning, sometimes in the form of sodium diacetate and it is often used to give potato chips a salt and vinegar flavor. As the conjugate base of acetic acid, a solution of sodium acetate and this is useful especially in biochemical applications where reactions are pH-dependent in a mildly acidic range. Sodium acetate is used in heating pads, hand warmers. Sodium acetate trihydrate crystals melt at 136.4 °F/58 °C, when they are heated past the melting point and subsequently allowed to cool, the aqueous solution becomes supersaturated. This solution is capable of cooling to room temperature without forming crystals, by pressing on a metal disc within the heating pad, a nucleation center is formed, causing the solution to crystallize back into solid sodium acetate trihydrate. The bond-forming process of crystallization is exothermic, the latent heat of fusion is about 264–289 kJ/kg. For laboratory use, sodium acetate is inexpensive and usually purchased instead of being synthesized and it is sometimes produced in a laboratory experiment by the reaction of acetic acid, commonly in the 5–8% solution known as vinegar, with sodium carbonate, sodium bicarbonate, or sodium hydroxide. Any of these reactions produce sodium acetate and water, carbonic acid readily decomposes under normal conditions into gaseous carbon dioxide and water. This is the taking place in the well-known volcano that occurs when the household products, baking soda. CH3COOH + NaHCO3 → CH3COONa + H2CO3 H2CO3 → CO2 + H 2O Industrially, sodium acetate is prepared from glacial acetic acid and sodium hydroxide. CH3COOH + NaOH → CH3COONa + H2O Sodium acetate can be used to form an ester with an alkyl halide such as bromoethane, hot Ice – Instructions, Pictures, and Videos How Sodium Acetate heating pads work
9.
Conjugate acid
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A conjugate acid, within the Brønsted–Lowry acid–base theory, is a species formed by the reception of a proton by a base—in other words, it is a base with a hydrogen ion added to it. On the other hand, a base is merely what is left after an acid has donated a proton in a chemical reaction. Hence, a base is a species formed by the removal of a proton from an acid. A proton is a particle with a unit positive electrical charge, it is represented by the symbol H+ because it constitutes the nucleus of a hydrogen atom, that is. A cation can be an acid, and an anion can be a conjugate base, depending on which substance is involved. In an acid-base reaction, an acid plus a base reacts to form a conjugate base plus a conjugate acid, refer to the following figure, We say that the water molecule is the conjugate acid of the hydroxide ion after the latter received the hydrogen proton donated by ammonium. On the other hand, ammonia is the base for the acid ammonium after ammonium has donated a hydrogen ion towards the production of the water molecule. The strength of an acid is directly proportional to its dissociation constant. If a conjugate acid is strong, its dissociation will have an equilibrium constant. The strength of a base can be seen as the tendency of the species to pull hydrogen protons towards itself. If a conjugate base is classified as strong, it will hold on to the hydrogen proton when in solution, if a chemical species is classified as a weak acid, its conjugate base will be strong in nature. This can be observed in ammonias reaction with water, the reaction proceeds until most of the ammonia has been transformed to ammonium. This shift to the right in the equilibrium of the reaction means that ammonium does not dissociate easily in water. On the other hand, if a species is classified as a strong acid, an example of this case would be the dissociation of Hydrochloric acid HCl in water. Since HCl is an acid, its conjugate base will be a weak conjugate base. Therefore, in system, most H+ will be in the form of a Hydronium ion H 3O+ instead of attached to a Cl anion. To summarize, the stronger the acid or base, the weaker the conjugate, the acid and conjugate base as well as the base and conjugate acid are known as conjugate pairs. When finding a conjugate acid or base, it is important to look at the reactants of the chemical equation, to identify the conjugate acid, look for the pair of compounds that are related
10.
Salt (chemistry)
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In chemistry, a salt is an ionic compound that results from the neutralization reaction of an acid and a base. Salts are composed of related numbers of cations and anions so that the product is electrically neutral and these component ions can be inorganic, such as chloride, or organic, such as acetate, and can be monatomic, such as fluoride, or polyatomic, such as sulfate. There are several varieties of salts, salts that hydrolyze to produce hydroxide ions when dissolved in water are alkali salts, whilst those that hydrolyze to produce hydronium ions in water are acidic salts. Neutral salts are those salts that are neither acidic nor basic, zwitterions contain an anionic centre and a cationic centre in the same molecule, but are not considered to be salts. Examples of zwitterions include amino acids, many metabolites, peptides, usually, non-dissolved salts at standard conditions for temperature and pressure are solid, but there are exceptions. Molten salts and solutions containing dissolved salts are called electrolytes, as they are able to conduct electricity. As observed in the cytoplasm of cells, in blood, urine, plant saps and mineral waters, therefore, their salt content is given for the respective ions. Salts can appear to be clear and transparent, opaque, and even metallic, in many cases, the apparent opacity or transparency are only related to the difference in size of the individual monocrystals. Since light reflects from the boundaries, larger crystals tend to be transparent. The color of the salt is due to the electronic structure in the d-orbitals of transition elements or in the conjugated organic dye framework. Different salts can elicit all five basic tastes, e. g. salty, sweet, sour, bitter, and umami or savory. Salts of strong acids and strong bases are non-volatile and odorless and that slow, partial decomposition is usually accelerated by the presence of water, since hydrolysis is the other half of the reversible reaction equation of formation of weak salts. Many ionic compounds can be dissolved in water or other similar solvents, the exact combination of ions involved makes each compound have a unique solubility in any solvent. The solubility is dependent on how well each ion interacts with the solvent, for example, all salts of sodium, potassium and ammonium are soluble in water, as are all nitrates and many sulfates – barium sulfate, calcium sulfate and lead sulfate are examples of exceptions. However, ions that bind tightly to each other and form highly stable lattices are less soluble, for example, most carbonate salts are not soluble in water, such as lead carbonate and barium carbonate. Some soluble carbonate salts are, sodium carbonate, potassium carbonate, solid salts do not conduct electricity. Moreover, solutions of salts also conduct electricity, the name of a salt starts with the name of the cation followed by the name of the anion. Salts are often referred to only by the name of the cation or by the name of the anion. g
11.
Acetate disc
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They are made for special purposes, almost never for sale to the general public. They can be played on any normal record player but will suffer from wear more quickly than vinyl, some acetates are highly prized for their rarity, especially when they contain unpublished material. Acetates are usually made by dubbing from a recording in another medium. Within the vinyl record industry, acetates are used for evaluating the quality of the tape-to-disc transfer. The term acetate derives from the used in examples cut before 1934. Cellulose acetate was only in use for a short while, lower-quality blanks were considered adequate for non-critical uses such as tests and demo discs. One pump usually provides suction for both the turntable and the tube that pulls away the fine string of nitrocellulose lacquer removed by the groove-cutting stylus. Acetates have not always been used solely as a means of evaluating a tape-to-disc transfer or cutting the master disc. They were widely used for many purposes before magnetic tape recorders became common and they were used extensively in Jamaica by sound system operators in the late 1940s and 1950s. Acetates were often used as demos of new recordings by artists, before the introduction of magnetic tape for mastering, disc recording was done live, although sometimes intermediate disc-to-disc editing procedures were involved. Acetate blanks allowed high-quality playable records to be produced instantaneously, acetates were widely used in radio broadcasting to archive live broadcasts, pre-record local programming, and delay network feeds for broadcast at a later time. Sixteen-inch discs recorded at 33⅓ rpm were used for these one-off electrical transcriptions beginning in the mid-1930s, around 1940, disc recorders designed for amateur home use began appearing on the market, but their high prices limited sales and then World War II brought their production to a halt. After the war, the popularity of such recorders greatly increased, countless discs were cut at parties and family gatherings, both for immediate amusement value and to preserve audio snapshots of these events and of the voices of relatives and friends. Acetate discs are less durable than some types of magnetic tape. In preparation for a pressing, acetates are used for quality control prior to the production of the stampers. The actual stampers can be either from normal acetates, or from a DMM disc. In the dance world, DJs cut new or otherwise special tracks on acetates, in order to test crowd response. This practice started as early as in the 1960s in Jamaica and these discs are known as dubplates
