2.  Water (H2O) is the most abundant
compound on Earth's surface, covering 70
percent of the planet.

3.  In nature, water is present in the states of
liquid, solid and gas. It is a dynamic
equilibrium between liquid and gas states
at standard temperature and pressure. At
room temperature, the liquid is tasteless
and odorless, nearly colorless with a hint
of blue. Many substances are dissolved in
water and is commonly referred to as the
universal solvent. Therefore, the water in
nature is rarely pure and some of the
properties may differ from those of the
pure form of it. However, there are also
many compounds which are substantially,
if not completely insoluble in water. Water
is the only common substance found
naturally in the three common states of
matter and is essential for life on Earth.
Water makes up 55% to 78% of the human
body.

4.  Water is a chemical compound
with the chemical formula
H2O: one water molecule has
two hydrogen atoms covalently
bonded to one atom of oxygen.
Water occurs naturally in three
states of matter (solid, liquid
and gas) and can take various
forms on the Earth surface:
water, vapor and clouds in the
sky, the sea water in the oceans,
the oceans, glaciers, polar
glacier mountains, fresh and
salt water, lakes, rivers.

5. The main physical and chemical
properties of water are:
 Water is a liquid at normal temperature and pressure. It is tasteless and
odorless. Water and ice are of light blue hue, although both appear
colorless in small quantities. Water in a vapor state is essentially
invisible.

6.  Water is transparent in the visible range
of the electromagnetic spectrum. Thus
aquatic plants can live in water because
sunlight can reach them. Infrared
radiation is strongly absorbed by oxygen
or hydrogen bonds with OH. Since the
water molecule is not linear, and the
oxygen atom has a higher
electronegativity than hydrogen atoms,
an oxygen atom is converted to a small
negative charge and the hydrogen atoms
are slightly positive. As a result, water is
bipolar with the electric dipole moment.
Water also may be a very large number
of hydrogen bonds (four) in the
molecule's size. These factors lead to
strong attractive forces between the
water molecules, resulting in high
surface tension and capillary forces.
Capillarity refers to the tendency of
water to pass a narrow tube against the
force of gravity. This property is relied
upon by all vascular plants, such as
trees.

7.  Water is a good polar solvent
and is often referred to as the
universal solvent. Substances
which are soluble in water, for
example, salts, sugars, acids,
bases, and certain gases - in
particular oxygen and carbon
dioxide (carbonation) - are
known as hydrophilic (water
loving) substances, while those
which are miscible with water
(for example, fats and oils), are
known as hydrophobic (water-fearing)
substances.

8.  All the components in the cells
(proteins, DNA, and
polysaccharides) are dissolved in
water, the discharge structure and
activity of their interaction with
water. A pure water is of low
electrical conductivity, but the
conductivity increases with
additional small amount of
dissolved ionic material such as
sodium chloride. A boiling point
of water (and all other liquids) is
dependent on the atmospheric
pressure. For example, on the top
of Mount Everest, water boils at a
temperature of 68 ° C (154 ° F),
compared to 100 ° C (212 ° F) at the
sea level. Conversely, water deep in
the ocean, near geothermal wells,
can reach temperatures of
hundreds of degrees and remain
liquid.

9.  At 4181.3 J the water has
a high heat capacity,
and a large amount of
heat of vaporization
(40.65 kJ · mol-1), both
of which are the result
of extensive hydrogen
bonds between the
molecules. These two
unique properties allow
water to moderate
climate of the Earth by
buffering temperature.
Density fluctuations in
liquid water is 1000 kg /
m 3 (62.43 lb / ft Cu) at
4° C. The ice has a
density of 917 kg / m 3
(57.25 kg / cu ft).

10.  The maximum density of water
occurs at 3.98 ° C (39.16 ° F). The
best known chemical substances
have become more compact,
however, as the cooling water has
the property of becoming less
dense when cooled to form a solid
ice. As the water is cooled, there
are two competing effects: 1)
reducing the volume and 2)
increasing the total volume of
liquid, as the particles orient in an
organized structure of ice.
Between 3.98 ° C and 0 ° C, the
second effect as the effect cancels
the first effect is the increase in
volume as the temperature drops.
Water expands to occupy 9%
larger volume of the ice, which is
the fact that the ice floats on
liquid water as icebergs.

11.  The water is mixed with many liquids, such as ethanol, in any proportions,
forming a single homogeneous liquid. On the other hand, water and most of
the oil, normally do not mix to form a thick liquid layer, at least one upper
layer, and the most dense layer at the bottom. Water forms an azeotrope with
many other solvents. Water can be divided by the electrolysis into hydrogen
and oxygen. Water is not a fuel, it is the final product of hydrogen
combustion. Elements which are more electropositive than hydrogen such as
lithium, sodium, calcium, potassium and cesium hydrogen are displaced with
water to form hydroxides. Being a flammable gas, hydrogen is very dangerous,
flammable and explosive when put in the reaction with water.

12. Thank you for watching
the presentation
GROUP 2
Patrycja Orman- Poland
Wiktoria Waniak – Poland
Zuzanna Pruchniak -Poland
Gloria Fernández Barbusano - Spain
Alba García Gómez - Spain
Eduardo González Anelo - Spain
Abraham González Guisado - Spain
Janet González Rodríguez - Spain
Adriana Mañero Santana - Spain
Pascal - Germany