the ability to supply 1 A for 1 hr, or
the equivalent.
bauxite The chief ore of aluminium, consisting of hydrous aluminium oxides and aluminous
laterite. It is a claylike amorphous
material formed by the weathering
of silicate rocks under tropical conditions. The chief producers are Australia, Guinea, Jamaica, Russia, Brazil,
and Surinam.
b.c.c. Body-centred cubic. See cubic
crystal.
beam balance See balance.
Beattie–Bridgman equation An
*equation of state that relates the
pressure, volume, and temperature
of a gas and the gas constant. The
Beattie–Bridgman equation uses empirical constants to take into account
the reduction in the effective number of molecules due to various types
of molecular aggregation. It is given
by
P = RT(1 – ε)(V + B)/V
2 – A/V
2 ,
where P is the pressure, T is the thermodynamic temperature, V is the
volume, R is the gas constant, and A,
B, and ε are constants related to Üve
empirical constants A 0 , B 0 , a, b, and c
by: A = A 0 (1 – a/V), B = B 0 (1 – b/V), and
ε = c/VT
3
.
Beckmann rearrangement The
chemical conversion of a ketone
*oxime into an *amide, usually using
sulphuric acid as a catalyst. The reaction, used in the manufacture of
nylon and other polyamides, is
named after the German chemist
Ernst Beckmann (1853–1923).
Beckmann thermometer A thermometer for measuring small
changes of temperature (see illustration). It consists of a mercury-in-glass
thermometer with a scale covering
only 5 or 6°C calibrated in hundredths of a degree. It has two mercury bulbs, the range of temperature
to be measured is varied by running
mercury from the upper bulb into
the larger lower bulb. It is used particularly for measuring *depression
of freezing point or *elevation of
boiling point of liquids when solute
is added, in order to Ünd relative molecular masses.
bauxite
60
b
5
4
3
2
1
0
reservoir for
adjusting range
scale for measuring
temperature change
stem
Beckmann thermometer
becquerel Symbol Bq. The SI unit
of activity (see radiation units). The
unit is named after the discoverer of
radioactivity A. H. *Becquerel.
Becquerel, Antoine Henri
(1852–1908) French physicist. His
early researches were in optics, then
in 1896 he accidentally discovered
*radioactivity in Ûuorescent salts of
uranium. Three years later he
showed that it consists of charged
particles that are deÛected by a magnetic Üeld. For this work he was
awarded the 1903 Nobel Prize for
physics, which he shared with Pierre
and Marie *Curie.
Beer–Lambert law A law relating
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the equivalent.
bauxite The chief ore of aluminium, consisting of hydrous aluminium oxides and aluminous
laterite. It is a claylike amorphous
material formed by the weathering
of silicate rocks under tropical conditions. The chief producers are Australia, Guinea, Jamaica, Russia, Brazil,
and Surinam.
b.c.c. Body-centred cubic. See cubic
crystal.
beam balance See balance.
Beattie–Bridgman equation An
*equation of state that relates the
pressure, volume, and temperature
of a gas and the gas constant. The
Beattie–Bridgman equation uses empirical constants to take into account
the reduction in the effective number of molecules due to various types
of molecular aggregation. It is given
by
P = RT(1 – ε)(V + B)/V
2 – A/V
2 ,
where P is the pressure, T is the thermodynamic temperature, V is the
volume, R is the gas constant, and A,
B, and ε are constants related to Üve
empirical constants A 0 , B 0 , a, b, and c
by: A = A 0 (1 – a/V), B = B 0 (1 – b/V), and
ε = c/VT
3
.
Beckmann rearrangement The
chemical conversion of a ketone
*oxime into an *amide, usually using
sulphuric acid as a catalyst. The reaction, used in the manufacture of
nylon and other polyamides, is
named after the German chemist
Ernst Beckmann (1853–1923).
Beckmann thermometer A thermometer for measuring small
changes of temperature (see illustration). It consists of a mercury-in-glass
thermometer with a scale covering
only 5 or 6°C calibrated in hundredths of a degree. It has two mercury bulbs, the range of temperature
to be measured is varied by running
mercury from the upper bulb into
the larger lower bulb. It is used particularly for measuring *depression
of freezing point or *elevation of
boiling point of liquids when solute
is added, in order to Ünd relative molecular masses.
bauxite
60
b
5
4
3
2
1
0
reservoir for
adjusting range
scale for measuring
temperature change
stem
Beckmann thermometer
becquerel Symbol Bq. The SI unit
of activity (see radiation units). The
unit is named after the discoverer of
radioactivity A. H. *Becquerel.
Becquerel, Antoine Henri
(1852–1908) French physicist. His
early researches were in optics, then
in 1896 he accidentally discovered
*radioactivity in Ûuorescent salts of
uranium. Three years later he
showed that it consists of charged
particles that are deÛected by a magnetic Üeld. For this work he was
awarded the 1903 Nobel Prize for
physics, which he shared with Pierre
and Marie *Curie.
Beer–Lambert law A law relating
www.AzShimi.ir www.AzShimi.com