椅子的英语单词水的性质论文中英文资料对照外文翻译文献

2021年1月20日发(作者：我受不了了)






水的性质论文

中英文资料对照外文翻译文献


Properties of water

Water
is
the
phase
in
which
all
the
main
processes
take
place
in
flotation.
The
processes

that

affect

the

surface

characteristics

of

particles

in

water

include
dissociation
of
dissolved
species,
hydration,
and
the
adsorption
of
ions
and
flotation reagents. Therefore, it is important to know the properties of water.
Water
is
a
polar
compound
and
water
molecules
interact
with
each
other
by
attractive
forces
called

van
der
Waals
forces.
These
forces
are
closely
related
to
the
polar structure of molecules. As well known, positive charges repel positive charges and
negative
charges
repel
negative
charges,
but
positive
charges
attract
negative
charges.
As a consequence, dipole molecules tend to
take a position
so
that attraction between
molecules
occurs.
This
phenomenon
is
called
Keesom
orientation.
Brownian
motion
disturbs the orientation. A dipole can also induce a dipole moment in

another molecule
causing attraction between the molecules. The phenomenon is called Debye induction.
Nonpolar molecules do also interact with each other. In all atoms and molecules the
continuous
motion
of
negative
electrons
creates
rapidly
fluctuating
dipoles
with
the
positive
nucleus
causing

attractive
forces.
These
forces
are
called
dispersion
or
London-van der Waals forces. The interaction of nonpolar molecules is caused by the
dispersion forces but with polar molecules, such as water, also the Keesom orientation
and the Debye induction forces occur. The total van der Waals interactions between two
atoms
or
molecules
are
given
by
the
sum
of
those
due
to
orientation,
induction
and
dispersion
forces.
The
orientation
interaction
is
significant
only
if
dipole
moment
is

high.

The
induction
interaction
is
always
small.
According
to
Coulomb’s
law
electrostatic forces vary
inversely
with
the second power of the distance
between two
charges.
The
interaction
due
to

van

der
Waals
forces
is
much
weaker.
The
forces
decay inversely with the sixth power of the distance between molecules. When atoms or
molecules
come
very
close
to
each
other
their
electron
clouds
repel
each
other.
Therefore, the resultants of van der Waals forces contain both attraction and repulsion
terms.

1


In addition to van der Waals forces, hydrogen bonding is characteristic for water
(Fig. 1). Hydrogen bonding occurs when an atom is attracted by rather strong forces to
two atoms instead of

only one, so that it may be considered to act as a bond between
them. In water the hydrogen atom is covalently attached to the oxygen (about470 kJ/mol)
but
has
additional
attraction
(about
23.3
kJ/mol)
to
a
neighbouring
oxygen
atom
of
a
water
molecule.
The
bond
is
partly
(about
90%)
electrostatic
and
partly
(about
10%)
covalent
(Isaacs
et
al.,
2000,
Suresh
and
Naik,
2000).
Typically
hydrogen
bonding
occurs
where
the
partially
positively
charged
hydrogen
atom
lies
between
partially
negatively
charged
oxygen
and
nitrogen
atoms,
but
is
also
found
elsewhere,
such
as
between fluorine atoms in HF2, and between water and smaller halide ions F
-
, Cl
-

and
Br
-
.
Water appears to be a simple compound but it has many specific properties. Water
molecules
form
an
infinite
hydrogen-bonded
network
with
localized
and
structured
clustering.
According
to

the
present
view,
these
clusters
may
contain
4-12
water
molecules but much larger clusters have been suggested to occur (Chaplin, 2000). The
lifetime
of
the
structured
clusters
is
very
short,
pico
seconds
in
magnitude.
Several
models
have
been
suggested
for
the
structure
of
liquid
water
but
no
model
is
able
to
describe all the anomalous properties of water so far.

H

O


H
H
O


H

O

H
H
H

O

O

H

H
H

Figure 1. Schematic representation of hydrogen bonding of water molecules.

Ions destroy the natural hydrogen bonded network of water. If the energy of inter-
action between an ion and water dipoles is
greater than the mutual attraction of water
dipoles, the ion will be

hydrated. Water molecules are oriented around the ion forming
new
structures.
The
degree
of
hydration
depends
on
the
size
and
valence
of
the
ion.
Anions
are
hydrated
more
strongly
than

cations
of
the
same
size
because
hydrogen
atoms
of
water
can
approach
closer
than
oxygen
atoms
of
water.
Ions
that
exhibit
weaker
interactions
with
water
than
water
itself
are
known
as

structure-
breakers,

2


whereas ions that interact strongly with water are known as structure- makers.
Small
ions
are
strongly
hydrated
creating
local
order
and
higher
local
density.
Large monovalent ions, such as Cs+


and I-, are very weakly solvated. Their surface
charge
density
is
low
and
they
may
be
pushed
on
by
strong
water-water
interactions.
Their translational movement is high. Single

atom ions may also be found in clathrate
structures,
where
the
lattice
of
water
contains
cavities
that
are
capable
of
enclosing
molecules without any bonds between them. Smaller ions, such as Rb+

and K+, cause
the
partial
collapse
of
clathrate
structures,
through
puckering,
increasing
the
local
mobility of water molecules. The smallest
ions hold
strongly to
the first
shell of their
hydrating
water
molecules
and
hence
there
is
less
localized
water
molecule
mobility.
Divalent and trivalent ions are always more strongly solvated than monovalent ions. In
the primary hydration shell the water molecules are most restricted in their motion but
the effect does not end there. In the second hydration shell the water molecules are freer
to
rotate
and
exchange
with
bulk
water,
and
so
on.
The
position
of
hydrated
water
molecules
on
anions
and
cations
is
different
and
so
is
their
ability
to
form
hydrogen
bonds.
Altogether,
the
properties
of
water
depend
on
all
the
ions
and
their
characteristics.
Ions and their hydrations affect the properties of water, such as viscosity, in many
ways. Hydration is an exothermic process. During the formation of the internal layers of
hydrated sheaths

there is a considerable quantity of heat evolved. During the formation
of
the
subsequent
layers

the
amount
of
heat
gradually
decreases.
If
temperature
is
increased,
the
hydration
of
ions
decreases.
This
is
explained
so
that
the
rotational
movement of water molecules hinders their orientation.
The
increase
of
orientation
and
the
stability
of
the
oriented
dipoles
decrease
the
solubilizing properties of water. The solvent action of water is closely connected with
the hydration of the dissolved ions. If the dipoles of water are already polarized then the
hydration of new ions by these water molecules is hindered. For the same reason, the
conditions for the diffusion of ions become more difficult in polarized water. In addition,
hydrated layers can prevent the adsorption of reagents on particles.
The
ionic
composition
of
water
is
determined
by
the
solubility
of
particles.
Minerals are soluble if their hydration energy exceeds the lattice energy. Ion hydration
energy increases as the valence of the ion increases and the ionic radius decreases. Also,
the energy of crystal lattice increases. However, hydration energy increases much more
slowly as ion valence increases than does crystal lattice energy. Therefore, an increase in
valence is accompanied by a great reduction in solubility. This is why the sulphides and
oxides
of
bivalent
metals
are
relatively
insoluble
in
water.
The
rate
of
dissolution
depends on the nature of the mineral, the temperature and pH of the pulp, the intensity
of
agitation,

particle
size
and
the
specific
surface
of
the
particles,
and
the
ionic

3


composition of water.
The specific surface of particles determines the overall area that is in contact with
water
and,
consequently,
the
number
of
ions
that
are
transferred
into
the
solution
per
unit of time. The intensity of agitation determines the movement of ions away from the
surface of particles. These factors affect the kinetics of dissolution.
The temperature and pH of the pulp do not affect only the kinetics of dissolution
but also the equilibrium concentrations of the dissolved substances. In most cases, the
solubility of minerals increases with an increase in temperature. This is due to the higher
vibrational energy of the constituents in the crystal lattice, and at the same time due to
the decreased forces between the ions,

which facilitates the penetration of water into
the lattice.
Ionic
equilibrium
and
solubility
are
important
characteristics
of
solutions
and
of
chemical reactions that occur in water. A chemical reaction in solution is possible when,
on collision of ions, molecules are formed in which forces of cohesion between atoms
exceed the forces of hydration. A requirement for a reaction to proceed is a removal of
ions
from
the
solution
in
the
form
of
weakly

dissociated
molecules
or
nearly

insoluble

substances,

i.e.

as

precipitate

or

as

gas.

At

the

high

ionic
concentration of a weakly soluble substance the solubility decreases. The solubility of
minerals depends on complexes that are formed in each particular case. If the solution
contains similar ions than the mineral, the solubility is decreased.



2


外文翻译

水的性质

水是相在浮选中，所有的主要过程。

进程，影响水粒子的表面特性，包括
溶 解物种，水化分离，吸附离子浮选试剂。因此，重要的是知道水的性质。

水是极性化合物和水 分子相互影响的，
由有吸引力部队称为范德华力。
这些
部队是密切相关的极地分子结构 。
众所周知，
正电荷排斥正电荷，
负电荷排斥负
电荷，正电荷吸引负电荷。因 此，偶极分子往往采取的立场，所以，景点之间分
子发生。这种现象称为
Keesom
方向。布朗运动扰乱的方向。偶极子也可以诱导
偶极矩在另一个分子，造成分子之间的吸引力。这种现象 被称为德拜感应。

非极性分子也互相交流。
在所有的原子和分子的连续负电子运动迅 速创建与
波动的偶极子正电的原子核，造成引力。这些部队被称为分散或伦敦范德华力。
非极性 分子的相互作用所造成的但与极性分子，如供水，也
Keesom
方向的色散
力和德拜 感应部队发生。总范德华相互作用两个原子或分子的总和，由于取向，
诱导色散力。
方向的相互 作用是重要的，
只有偶极矩是很高的。
感应互动始终是
小。
根据库仑定律静电 作用力变化成反比两个之间的距离第二个权力收费。
由于
范德华力的相互作用要弱得多。
部队第六电源与分子之间的距离成反比衰减。
当
原子或分子非常接近对方的电子云互相排斥。
因此，
范德华力的生成物中含有吸
引和排斥条款。

除了范德华力， 氢键是水的特点（图
1
）
。当一个原子是由相当强大的力量
所吸引，
氢键发生两个原子，
而不是只有一个，
因此它可考虑作为债券在他们之
间。在水中的氢 原子共价连接到氧气（约
470
千焦耳
/
摩尔）
，但有额外的吸引力
（约
23.3 kJ / mol
的）
，到邻近的一个水分子的氧原子。债券 部分（约
90
％）静
电和部分（约
10
％）共价（艾萨克斯等人，< br>2000
年，
Suresh
和奈克，
2000
年）
。
通常氢键发生在部分带正电的氢原子所在之间的部分负电荷的氧和氮原子，
但也
发现其 他地方，如在
HF
2
氟原子之间，与水和更小卤离子的
F
-
，
CL
-
和
Br
-
。

水似乎是一个简单 的化合物，
但它有许多特定的属性。
水分子形成无限的氢
键网络的本地化和结构性聚类 。根据目前的观点，这些簇可能包含
4-12
水分子，
但更大的集群已发生（卓别林，
2000
）
。

“结构性集群的寿命很短，微微秒的幅
度。
几个模型已建议为液态水的结构，
但没有模型能够到目前为止描述异常水的
所有属性。

图
1
。氢的水分子结合的示意图。

离子破坏自然的氢水 的氢键网络。
如果间的能量离子和水偶极子之间的行动
是大于水的相互吸引偶极子，
离 子水化。
水分子是面向周围的离子形成新的结构。
水化程度取决于的大小和价离子。
阴 离子水合更强烈，
比相同大小的阳离子，
因

1