Chapter 2 | Properties of Water Flashcards
one of the most important things
on earth.
Water
Without water, there could be
no traces of life on earth because both
__________and ____________
depend on the availability of water.
photosynthesis; animal metabolism
___________properties of water not
only return the water from the
atmosphere but also affect the
concentration and composition of the
remaining water and thus its sustainability
to the biota.
evaporative
In return, the water that returns to the
atmosphere has a major effect on the
climate by its effect on _____________
atmospheric heat transfer
It also determine the time lags
exhibited in heating and cooling that affect
the stratification of lakes.
physical characteristics of water
responsible for the existence of aquatic
systems
physical characteristics of water
a simple molecule composed of
two positively charged hydrogen atoms
and a negatively charged oxygen atom that
are covalently bonded.
Water
Molecules of the water
two positively charged hydrogen atoms
and a negatively charged oxygen atom that
are covalently bonded.
Molecules of the water
two positively charged hydrogen atoms
and a negatively charged oxygen atom that
are covalently bonded.
it dictates how water
interacts with other molecules.
polarity
the charge differential of water
polarity
the measure of mass per volume.
Density
d=m/v
The average density of an object equals its
total mass divided by its total volume.
The density of
water
about 775 times greater than the air
they do not need strong stems or skeletons
required on land.
large aquatic organisms
reason for frequent cracking of expanding lake ice
due to expansion of the water surface upon freezing
This plays an important role in the mechanical breakdown of rock.
“physical weathering”
Periodic freezing and thawing is effective in shattering rock and exposes more rock surface to dissolution
“biological/ chemical weathering”
measure of liquid’s resistance
to flow and is responsible for the frictional resistance or viscous drag that water offers to swimming fish or sinking algae.
Dynamic viscosity
The reciprocal of viscosity
“fluidity”
a measure of ease of flow
fluidity
it plays a very important role in
temperature regulation.
water
The characteristic of water to attract to
other substances.
Adhesion
The characteristic of water to attract to
another water molecule.
Cohesion
This allows the
development of surface tension.
Cohesion
water has a great strength on its surface film.
Surface Tension
it permits surface-living insects to walk on
water and light-weight debris, like pollen, to float,
resulting in accumulations of wind- or current-derived particulate matter in the surface film of lakes and seas.
Surface Tension
Why is that Water is a good solvent for inorganic and polar organic molecules?
because it has high pole dipole moment with
positively-charged hydrogen atoms of each molecule and the oxygen atom negatively charged.
Allows lake stratification, and surface freezing
rather than bottom freezing
Density
Allows water to exist as liquid
Melting and
Boiling Points
Influences the case of water mixing, provides
resistance to the movement of organisms, and
helps determine the sedimentation rate of
particles
Viscosity
Moderates (buffers) temperature extremes
Specific Heat or
Heat capacity
Important to heat transfer in inland water and atmosphere
Heat of Vaporization
Increase the difficulty of surface waves breaking
and thereby slowing the rate of heating and
cooling in lakes, allows certain insects to walk on
water surfaces
Surface Tension
Allows greater heat absorption in the surface
water, but reduced surface absorption at shorter
wavelengths, allowing a greater penetration of
photosynthetically available radiation
Absorption or Radiation
Important in dissolution and transport of
dissolved substances from catchments and the
atmosphere to aquatic systems
Solvent Properties
Why do dead fish generally sink faster
than bacteria, even they have
approximately same density?
What will happen if you drop a needle on
a glass of water vertically? What if
horizontally? Why did it happen?
What could be the dangerous effects to
the aquatic life of too much viscosity of
water in lakes?
What does it create when the positively charged hydrogens bind to the oxygen?
Asymmetrical molecule.
positive charge on one side and negative charge on the other side
Result of the high specific heat of water
Protect the biota from overheating and
Prevent rapid loss of water
Heat or energy needed to break hydrogen bonds allowing liquid water to become water vapour
Heat of evaporation/ heat of vaporization
What drives the water cycle?
Heat of vaporization and condensation
