Describe Water
Properties
of Water
Key Properties of Water
• Key properties of water include:
– states of matter
– polarity
– cohesion and adhesion
– capillary action
– high surface tension
– universal solvent
– high specific heat
– density and buoyancy
– high heat of vaporization
The Structure of Water
● Just like all matter, water is made of
________.
● Atoms attach together, or ________, to
form ______________.
● ____ hydrogen atoms bonded to an
________ atom form a water molecule.
● A short way of writing this is to use
the chemical formula for water: ____.
• How would you describe water to someone who
had never seen it before?
• You might say that pure water has no _______,
no ________, and no _________. You might
even say that water is a rather plain, ordinary
substance.
• If you asked a chemist to describe water, the
chemist would say that water is very ________.
Its properties ________ from those of most
other familiar substances.
States of Matter
• Water covers about _____ of the
Earth’s surface.
• Water is the ______ substance on
Earth that occurs ________ as a solid,
liquid and gas.
The Atomic Structure of Water
● This shows how the hydrogen and oxygen
atoms are arranged in a water molecule.
● Each end of the molecule has a slight
____________ charge.
● The oxygen end has a slight ____________
charge.
● The hydrogen ends have a slight
____________ charge.
Polarity
● _______ molecule:
a molecule that
has electrically
charged
____________
Polarity
• The positive end of one water
molecule is ____________ to the
negative end of another molecule.
• Water molecules tend to ____________
together.
● Because water
consists of polar
water molecules,
it is called a polar
____________.
Cohesion and Adhesion
• ____________: water molecule
attracted to another
____________ molecule
• ____________: water molecule
attracted to another
Cohesion and Adhesion
• Cohesion causes the formation of
____________.
• Adhesion causes the ____________ to
stick to a ____________
_________________
Capillary Action
Capillary Action
• The next time you see a drink with a
straw in it, look closely at the level of
the liquid outside and inside the straw.
You will see that the liquid rises
____________ ____________ the straw.
• As water molecules are attracted to the
____________, they ____________ other
water molecules up with them. Similarly,
water will climb up into the ____________
of a brick or a piece of wood.
• ____________ and ____________ work
together to cause capillary action.
• ____________ action: the ____________
force of ____________ among water
molecules and with the molecules of
surrounding materials
– Allows water to move ____________
materials with pores inside.
Capillary Action
Surface Tension
• Have you ever watched water striders skate
across the ____________ of a pond without
____________?
• They are supported by the surface ________
of the water.
Surface Tension
Surface Tension
• Surface tension: the____________ across
the surface of water that is caused by the
________ molecules pulling on one another.
• The molecules at the surface are being
____________ by the molecules _________
to them and _________ them.
• The pulling forces the surface of the water
into a curved shape. Surface tension also
causes raindrops to form ____________
beads when they fall onto a car windshield.
Japanese 1 yen aluminum
coin on water
Universal Solvent
Universal Solvent
• What happens when you make a fruit drink
from a powdered mix? Or stir sugar into tea?
• As you stir the powder into the __________,
the powder seems to disappear. When you
make the fruit drink, you are making a
____________.
• A ____________ is a mixture that forms
when one substance dissolves
another.
• The substance that does the
dissolving is called the ____________.
Universal Solvent
• Water is known as the ____________
solvent because ____________
substances dissolve in it.
• Because of this, water is ____________
found in a ____________ ____________
condition.
Buoyancy
• ____________: ____________ force that
keeps things afloat
Density
• Density: relationship between the ________
of the substance and how much _________
it takes up (volume).
– The mass of atoms, their _________, and
how they are ______________ determine
the density of a substance.
Specific Heat
• It is a steamy summer day. The air is hot, the
sidewalk is hot, and the sandy beach is hot.
• But when you jump into the ocean, the water
is surprisingly _________! If you go for an
evening swim, however, the water is
_________ than the cool air.
Specific Heat
Specific Heat
• _________ heat: the amount of heat
_________ needed to increase the
temperature of a certain mass of a
substance by ______.
• Compared to other substances, water
requires a _____ of heat to increase its
temperature.
• Water’s high specific heat is due to the
strong __________ among water molecules.
• Other substances, such as air and rocks,
have _________ attractions between their
molecules.
– The temperature of each of these
substances rises more _________ than
that of water that is heated the _________
amount.
Specific Heat
High Heat of Vaporization
A large body of water can act as a heat sink -_________ heat from sunlight during the day and
summer and _________ heat during the night and
winter as the water gradually cools. As a result:
• Heat of vaporization: the amount of
energy required to _________ one
gram of a liquid substance to a gas
(__________________)
• Due to strong ____________, water
can absorb a lot of _________ before
molecules evaporate.
• Water, which covers three-fourths of the planet,
keeps temperature _________ within a range
suitable for life.
• Coastal areas have _________ climates than
inland.
• The marine environment has a relatively
_________ temperature.
Benefits of High Heat of Vaporization
• _________ the earth's climate.
– _________ cooling: solar heat
absorbed by tropical seas
dissipates when surface water
evaporates
– As moist tropical air moves toward
the poles, water vapor releases
_________ as it condenses into rain.
Benefits of High Heat of Vaporization
• Evaporative cooling also
– _____________ temperature in aquatic
ecosystems
– Helps organisms _________
overheating (when you sweat to cool
off)
Key Properties of Water
• Review:
– states of matter
– polarity
– cohesion and adhesion
– capillary action
– high surface tension
– universal solvent
– high specific heat
– density and buoyancy
– high heat of vaporization