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Subject: Music

This US group was formed in Los Angeles, California, in 1978 by Steve Allen (guitar, vocals) and Ron Flynt (bass, vocals), two expatriate musicians from Tulsa, Oklahoma. Drummer Mike Gallo ...

phonochemistry

phonochemistry   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
24 words

...The use of high-frequency sound (ultrasound, with a frequency greater than about 20 kHz) to induce or accelerate certain types of chemical...

benzopyrene

benzopyrene   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
22 words
Illustration(s):
1

...A crystalline aromatic hydrocarbon, C 20 H 12 ; m.p. 179°C. It is found in coal tar and is highly carcinogenic....

freezing mixture

freezing mixture   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
25 words

...mixture A mixture of components that produces a low temperature. For example, a mixture of ice and sodium chloride gives a temperature of −20...

cobalt steel

cobalt steel   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
40 words

...steel Any of a group of alloy steels containing 5–12% of cobalt, 14–20% of tungsten, usually with 4% of chromium and 1–2% of vanadium. They are very hard but somewhat brittle. Their main use is in high-speed...

oligosaccharide

oligosaccharide   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
36 words

...A carbohydrate (a type of sugar ) whose molecules contain a chain of up to 20 united monosaccharides. Oligosaccharides are formed as intermediates during the digestion of polysaccharides , such as cellulose and...

propanoic acid

propanoic acid   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
34 words

...acid ( propionic acid ) A colourless liquid carboxylic acid , CH 3 CH 2 COOH; r.d. 0.99; m.p. –20.8°C; b.p. 141°C. It is used to make calcium propanate – an additive in...

HNIW

HNIW   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
42 words
Illustration(s):
1

... ( hexanitrohexaazaisowurtzitane ) A powerful explosive, C 6 N 12 O 12 . It has a three-dimensional bridged structure containing six N-NO 2 groups. Also known as CL20 , it is extremely sensitive and so far has not been produced in bulk....

benzpyrene

benzpyrene   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
33 words

...A pale yellow solid, C 20 H 12 , m.p. 179°C, whose molecules consist of five fused benzene rings. It occurs in tars from coal and tobacco smoke and is a carcinogen...

phenyl methyl ketone

phenyl methyl ketone   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
49 words

...methyl ketone ( acetophenone ) A colourless, crystalline ketone with an odour of bitter almonds, C 6 H 5 COCH 3 , m.p. 20°C. It is made by treating benzene with ethanoyl chloride in the presence of aluminium chloride. It is used as a solvent and in making...

methanal

methanal   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
46 words

... ( formaldehyde ) A colourless gas, HCHO; r.d. 0.815 (at –20°C); m.p. –92°C; b.p. –21°C. It is the simplest aldehyde , made by the catalytic oxidation of methanol (500°C; silver catalyst) by air. It forms two polymers: methanal trimer and polymethanal. See also formalin...

sucrose

sucrose   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
53 words

... ( cane sugar , beet sugar , saccharose ) A sugar comprising one molecule of glucose linked to a fructose molecule. It occurs widely in plants and is particularly abundant in sugar cane and sugar beet (15–20%), from which it is extracted and refined for table sugar. If heated to 200°C, sucrose becomes...

earth’s atmosphere

earth’s atmosphere   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
53 words

...atmosphere The gas that surrounds the earth. The composition of dry air at sea level is: nitrogen 78.08%, oxygen 20.95%, argon 0.93%, carbon dioxide 0.03%, neon 0.0018%, helium 0.0005%, krypton 0.0001%, and xenon 0.00001%. In addition to water vapour, air in some localities contains sulphur compounds, hydrogen peroxide, hydrocarbons, and dust...

ammonia clock

ammonia clock   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
133 words

...by the vibrations of excited ammonia molecules. The ammonia molecule (NH 3 ) consists of a pyramid with a nitrogen atom at the apex and one hydrogen atom at each corner of the triangular base. When the molecule is excited, once every 20.9 microseconds the nitrogen atom passes through the base and forms a pyramid the other side: 20.9 microseconds later it returns to its original position. This vibration back and forth has a frequency of 23 870 hertz and ammonia gas will only absorb excitation energy at exactly this frequency. By using a crystal oscillator to...

Platonic hydrocarbons

Platonic hydrocarbons   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
152 words

...tetrahedron, the cube, the octahedron, the dodecahedron, and the icosahedron. These hydrocarbons have carbon atoms at the vertices of the polyhedra and single bonds along the edges. In fact, there are only two known Platonic hydrocarbons: cubane (C 8 H 8 ) and dodecahedrane (C 20 H 20 ). The hydrocarbon based on a tetrahedron (C 4 H 4 ) does not exist because of angle strain, but substituted derivatives C 4 X 4 are known. Angle strain is also the reason for the nonexistence of octahedrane (C 6 H 6 ) and icosahedrane (C 12 H 12 ). A major difficulty that has...

chlorite

chlorite   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
93 words

...minerals, usually green or white in colour, that are similar to the micas in structure and crystallize in the monoclinic system. Chlorites are composed of complex silicates of aluminium, magnesium, and iron in combination with water, with the formula (Mg,Al,Fe) 12 (Si,Al) 8 O 20 (OH) 16 . They are most common in low-grade metamorphic rocks and also occur as secondary minerals in igneous rocks as alteration products of pyroxenes, amphiboles, and micas. The term is derived from chloros , the Greek word for...

coal gas

coal gas   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
92 words

...gas A fuel gas produced by the destructive distillation of coal. In the late-19th and early-20th centuries coal gas was a major source of energy and was made by heating coal in the absence of air in local gas works. Typically, it contained hydrogen (50%), methane (35%), and carbon monoxide (8%). By-products of the process were coal tar and coke. The use of this type of gas declined with the increasing availability of natural gas, although since the early 1970s interest has developed in using coal in making SNG...

americium

americium   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
67 words

... (Symbol Am) . A radioactive metallic transuranic element belonging to the actinoids ; a.n. 95; mass number of most stable isotope 243 (half-life 7.95 × 10 3 years); r.d. 13.67 (20°C); m.p. 994 ± 4°C; b.p. 2607°C. Ten isotopes are known. The element was discovered by Glenn Seaborg and associates in 1945 , who obtained it by bombarding uranium–238 with alpha particles. https://www.webelements.com/americium/ Information from the WebElements...

holmium

holmium   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
73 words

... (Symbol Ho). A soft silvery metallic element belonging to the lanthanoids ; a.n. 67; r.a.m. 164.93; r.d. 8.795 (20°C); m.p. 1474°C; b.p. 2695°C. It occurs in apatite, xenotime, and some other rare-earth minerals. There is one natural isotope, holmium–165; eighteen artificial isotopes have been produced. There are no uses for the element, which was discovered by Per Cleve ( 1840–1905 ) and Jacques-Louis Soret in 1878 . https://www.webelements.com/holmium/ Information from the WebElements...

ammonium nitrate

ammonium nitrate   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
90 words

...below 32°C and monoclinic above 32°C. It may be readily prepared in the laboratory by the reaction of nitric acid with aqueous ammonia. Industrially, it is manufactured by the same reaction using ammonia gas. Vast quantities of ammonium nitrate are used as fertilizers (over 20 million tonnes per year) and it is also a component of some...

iridium

iridium   Quick reference

A Dictionary of Chemistry (8 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Science and technology, Chemistry
Length:
66 words

... (Symbol Ir) . A silvery metallic transition element ( see also platinum metals ); a.n. 77; r.a.m. 192.20; r.d. 22.42; m.p. 2410°C; b.p. 4130°C. It occurs with platinum and is mainly used in alloys with platinum and osmium. The element forms a range of iridium(III) and iridium(IV) complexes. It was discovered in 1804 by Smithson Tennant ( 1761–1815 ). https://www.webelements.com.iridium/ Information from the WebElements...

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