Download 18.12 Properties of Water

Properties of Water
SC.912.L.18.12
Polar bears spend most of their lives roaming the Arctic on large
sheets of floating ice, using them as platforms from which they
hunt seals when the seals make holes in the ice to breathe.
Rising average temperatures are causing these ice sheets to
diminish in size, putting stress on the polar bears' way of life. Ice
in a glass of water floats just like ice sheets in the arctic. What
characteristic of frozen water makes it float instead of sink?
A. The water traps air bubbles as it freezes, which makes it float.
B. Some of the water evaporates as it freezes, making the ice
lighter.
C. The molecules
molecules in
in ice
ice are
areless
lessdensely
denselypacked
packedthan
thanininliquid
liquid
water. water.
D. The ice molecules become polarized so they migrate upward
in the glass.
Citrus trees can be damaged or even killed if
temperatures stay below freezing long enough. On very
cold winter nights in Florida, the citrus growers turn on
the irrigation systems in the groves to spray water on
the trees, which forms a coat of ice on them.
There are several reasons why this is helpful in
protecting the trees. Which of the following is one of
these reasons?
A. Water releases
releases heat
heatas
asititfreezes.
freezes.
B. Ice protects the trees from wind chill.
C. Water keeps the trees from drying out.
D. Ice freezes the fruit so it won't rot.
Capillary action in plants allows water to be
transported through narrow tubes from the plants'
roots to their leaves, where it is used in photosynthesis.
This is possible because of the way water molecules
interact with each other and other materials. Water
molecules are most like which of the following in the
way they interact with each other?
A. ants
B. magnets
magnets.
C. balls
D. marshmallows
In places that get very little rainfall, such as the desert in
Arizona, daytime temperatures can get very high and
nighttime temperatures can get very low, often
dropping dramatically as soon as the Sun sets.
How would temperatures be different if there was more
water there?
A. not as hot
hot in
in the
the day
dayand
andwarmer
warmeratatnight
night
B. cooler in the day but still cold at night
C. very hot in the day and even colder at night
D. warmer in the day and warmer at night
Sometimes salt is used on roads to keep them free of ice. It
mixes with water and can flow into nearby lakes, where the
salty water sinks to the bottom, reducing the natural mixing
of the lake water and resulting in depleted oxygen levels for
aquatic life. When the salt first mixes with water, its crystals
come apart and are no longer visible. Why does salt react
this way in water?
A. The salt molecules form covalent bonds with the water
molecules and lose their crystal form.
B. The polarized water molecules make the salt crystals
become polarized as well.
C. The heat in the water makes the salt crystals melt so they
can't be seen.
D. The salt
salt molecules
molecules are
areionically
ionicallybonded
bondedand
andthe
thepolarized
water
molecules
pull them apart.
polarized
water molecules
pull them apart.
Plants are able to get water to come into their roots even
if the water in the soil is slightly downhill from the root.
What property of water molecules makes it possible for
this to happen?
A. The charged molecules in the soil push the polarized
water molecules away and force them into the roots.
B. The polarized
polarized water
watermolecules
moleculesstick
sticktotoeach
eachother
otherand
and
to the water
water molecules
moleculesalready
alreadyininthe
theroots
rootsand
andsoil.
soil
C. Water molecules only have three atoms, and they are
tiny enough that gravity won't affect them.
D. The water molecules begin to evaporate as the soil
warms, and they float uphill and into the roots.
Water molecules evaporate from lakes and rivers when
the Sun gives them enough energy to be able to escape
the hold of the other water molecules around them.
What makes these water molecules eventually form into
clouds and drop again as rain or snow, instead of
continuing to float around?
A. They are heavier than the air around them, so
eventually they will have to fall down.
B. Each water molecule expands when heated, making it
rise, and the molecules fall as they lose heat.
C. They are polarized,
polarized,so
sothey
theywill
willstick
sticktotoeach
eachother
otherasas
they lose heat
heat energy
energy and
andslow
slowdown.
down.
D. Once the water molecules hit a cloud, they give up
their heat to the cloud and fall down.
Some insects can walk on the surface of water. Their feet
push against the surface of the water and the water
surface bends down under their weight but does not
break. What do the individual water molecules do that
makes this possible?
A. The molecules push on the ones below them and only
sink a little.
B. The molecules
molecules hang
hang on
onto
toeach
eachother
otherbecause
becausethey
theyare
polarized.
are
polarized.
C. The polarized water molecules are drawn toward the
insect's feet.
D. The surface water molecules push on the insect as
they evaporate.
During the heat of the summer it is refreshing to cool
down in the ocean at the beach because water can
absorb more heat than land, the water does not increase
in temperature as fast because it has a high
a. Polarity
b.
b. Heat
Heatcapacity
capacity
c. Surface tension
d. Surface area
Water is essential for life. Its special properties make
water the single most important molecule in plant life.
Which of the following properties of water enables it to
move from the roots to the leaves of plants?
A. Water expands as it freezes.
B. Water is an excellent solvent.
C. Water
Waterexhibits
exhibits
cohesive
behavior.
cohesive
behavior.
D. Water is able to moderate temperatures.
OUT OF 10 QUESTIONS
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•
•
•
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1/10 = 10%
2/10 = 20%
3/10 = 30%
4/10 = 40%
5/10 = 50%
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•
•
•
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6/10 = 60%
7/10 = 70%
8/10 = 80%
9/10 = 90%
10/10 = 100%