Properties of Water
Links updated 9-9-2014
Table of Contents
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Unit 1
Properties of Water Lab
Date (unique to you)
Page (unique to you)
General Directions
Read information about the properties of
water and carry out the experiments using
the materials at your lab station.
 Write the Experimental Question as the title for this lab in
your lab notebook- not in the table of contents.
 Write the names of your lab partners at the beginning of
the lab.
Experimental Question:
What are the special
properties of water?
Partners
 Write the first and last names of your lab
partners in your lab notebook.
Objectives
Copy the objectives for this lab into your lab notebook:
Objectives
1. Describe the structure of water.
2. Explain the properties of water important to
supporting life on Earth.
 Write the vocabulary words and definitions in your lab
notebook. Use the links to get information.
 Do the activities to strengthen your understanding of each
concept.
 Answer all numbered questions in red in your lab notebook.
You do not have to write the question; although, your answer
should be in a complete sentence. Make sure you label each
section!
I. The Structure of Water
 Write this heading in your lab notebook .
 Answer all of the questions in RED in your
lab notebook.
Vocabulary
Define these words as you learn
about the structure of water.
Covalent bond
Polar covalent bond
Hydrogen bond
Structure of Water
(–)
(–)
O
H
(+)
H
(+)
 This is what a water molecule looks like.
 It is made of two hydrogen atoms connected by a
covalent bond to one oxygen atom. (Note the shape!)
Covalent Bonds in Water
(–)
(–)
The Hydrogen and Oxygen in
water are bonded covalently.
O
H
(+)
Review Covalent bonds here
H
(+)
1. _______(#) electrons are
shared to form a covalent bond.
2. Why does oxygen form 2 bonds
and hydrogen form one bond?
ACTIVITY
 Build a water molecule using the molecular model
pieces in the box. (blue is O and white is H) .
3. Draw a picture of water.
4. Write the chemical formula of water.
Water is Polar
(–)
(–)
5. Which atom is larger? O or H?
O
H
(+)
H and O atoms do not share the
electrons evenly.
H
The oxygen in water has more protons, so
the electrons tend to hang out at the
oxygen end of water, making that end of
the molecule slightly negative.
(+) This results in the two hydrogen atoms
becoming slightly positive.
 Add the + and – charges to your picture
of water.
Structure of Water
(–)
(–)
 The uneven charge/sharing of
electrons makes water POLAR.
O
H
(+)
Earth has a north
and south pole!
 Take a closer look at polarity by
watching the Ted Ed Video #1Polarity in my share drive.
H
(+)
 Polarity contributes to emergent
properties of water
Batteries have
+ and – pole!
6. What is polarity?
7. Why is water considered polar?
Hydrogen Bonds
 The H+ on one water molecule is attracted
to the O- of another water.
(–)
Hydrogen
bond
(+)
H
(+)
O
(–)
(–)
(+)
H (+
)
(–)
 This weak bond is called a hydrogen
bond.
 Each water molecule can hydrogen
bonds with 4 other water molecules.
 A single hydrogen bond is weaker than
a single covalent bond. However,
groups of hydrogen bonds are very
strong.
 Hydrogen bonds are responsible for the
“stickiness” of water molecules
 Click through this animation to learn
about water structure and hydrogen
bonding.
8. Why do hydrogen bonds form between water molecules?
9. Draw 4 water molecules connected by hydrogen bonds.
(Hydrogen bonds are drawn as dotted lines).
2. Water is the
Universal Solvent
Write this heading in your lab notebook
Answer questions for this section under that heading!
Vocabulary
Define these terms as you learn
about water and solutions.
 Solution
 Solvent
 Solute
 Hydrophobic
 Hydrophilic
Water is the ‘universal solvent’
 Solution = liquid consisting of uniform mixture of
two or more substances
 Two parts of a solution:
 Solvent = liquid (dissolving agent)
 Solute = substance dissolved
 EXAMPLE:
 Water = solvent;
Koolaid powder/sugar = solutes;
Kool-aid = solution
Remember the rule to make a
solution: “like dissolves like”
 Substances dissolve other substances that are
similar/“like” it.
 Because water is polar, it will dissolve ions and
other polar substances
 Hydrophilic = Water Lover
 See a Solution up close!
 Water will NOT dissolve anything nonpolar
Non polar molecules are hydrophobic
 Oil is an example of a nonpolar
molecule. It does not form hydrogen
bonds.
 Like dissolves like; therefore, oil
(nonpolar) does not mix with water
(polar).
 Nonpolar molecules are hydrophobic
(“afraid of water”) because they do not
mix with water.
** Click to the Solution part of this
animation (about halfway through)
10. Briefly explain what a solution is, as well as its parts.
11. You make hot cocoa in the morning by adding a cocoa
mix to a cup of hot water. Which is the solution, solute and
solvent in this scenario?
12. Why are oil and water NOT able to mix?
ACTIVITY 1
 Using the pipettes provided, add 2ml of
water to a test tube.
 Gently add 2 ml of cooking oil to the same
tube by tilting the test tube of water slightly
and letting the oil run slowly down the inside
of the test tube.
13. Describe what happened in your lab
notebook. Include the terms hydrophilic and
hydrophobic in your answer.
ACTIVITY 2
 Use a different test tube.
 Add 2ml of oil to the test tube.
 Gently add 2 ml of water to the same tube by
tilting the test tube of oil slightly and letting
the water run slowly down the inside of the
test tube.
14. Describe what happened. Include the terms
polar and non polar in your answer.
ACTIVITY 3
 Add a few drops of food coloring to each test
tube.
 Place your finger over the test tube and gently
shake to mix the oil and water.
15. What happens to the food coloring in each
test tube? Does it mix into the oil? Into the
water?
16. Is the food coloring polar or non polar? Is it
hydrophilic or hydrophobic
3. Water is Cohesive
and Adhesive
Write this heading in your lab notebook.
Answer questions for this section under that heading.
Vocabulary
Define these terms as you learn
how hydrogen bonds influence
the behavior of water.
Cohesion
Surface tension
Adhesion
COHESION
 Hydrogen bonding between water molecules
causes them to stick together.
 Cohesion between water molecules produces
SURFACE TENSION.
 The stickiness of water makes it seem as if it has
an invisible “skin” on the surface.
 Surface tension allows
this water strider to
walk across the surface
of a pond.
***Watch the video called “#2 - Surface tension &
cohesion” from the ISS found in my share drive.
And forms drops
on a blade of grass
ACTIVITY
 Use the pipet to gently drop water onto the
surface of a penny until a clear bubble has formed
on top but it is NOT overflowing.
17. How many drops could you put onto your
penny?
* Fill a beaker half full of water. Try to float a paper
clip on the surface.
18. Can you can float a paper clip on the water
surface of your penny?
19. What property of water allows you to do this?
The Trick to the Paper Clip
 Place a paper clip under the first
one. Then lower it into the water.
 The first should sink in. The second
will not break the Hydrogen bonds
and will float on top of the surface.
ACTIVITY
 Dry off your penny.
 With your finger, spread one small drop of detergent
on the surface of the dry penny.
 Fill the top of a penny with water until a clear bubble
has formed on top but it is NOT overflowing.
20. Describe the effect of the detergent.
 Did the detergent make a difference?
 Did the penny hold more, less or the same amount of
water?
ADHESION
 Polarity also causes water molecules to stick to other
substances.
Adhesion makes water cling to the sides of a glass cylinder.
21. List 3 examples you have seen of
water sticking to other objects.
** Watch the #3- Cohesion
and Adhesion video on my
share drive to observe these
properties aboard the ISS.
ACTIVITY
 What shape will a drop of of water form on:
(a) a piece of wax paper (nonpolar)
(b) a glass slide (polar)
 Perform the experiment. Place several drops of water on
the glass slide and several drops on the wax paper.
22. Draw and label the results on wax paper and glass.
Explain the differences in drop shape in terms of
adhesion - that is, the formation (or absence) of hydrogen
bonds between water and another substance.
CAPILLARY ACTION
 Water moves through a narrow
passage in a process called
capillary action.
 Capillary action describes how the
water molecules move against
gravity when placed in a narrow
passage.
Capillary Action
 Water is pulled to the top
of redwood trees as it
evaporates from leaves at
the top of the tree.
 ** Watch #4- Capillary
Action in my share drive
and #5- Cap. Action Time
Lapse in my share drive.
ACTIVITY
Use a beaker and a strip of paper towel (not folded
over) that is just long enough to hang over the side of
the beaker (inside) and reach almost to the bottom.
Place a single small drop of ink from a vis-a-vis pen on
the paper, about one inch from the bottom, and let it
dry completely.
(continued on next slide)
ACTIVITY
Put a small amount of water into the beaker and place
the strip of paper in the beaker so that the bottom end of
the paper is in water and the drop of ink is just above the
surface of the water.
Fold the paper over the top of the test tube. Use a paper
clip to hold it to the edge.
Note the starting time in your notebook.
23. Predict how long it will take for the water to reach
the top of the paper.
Watch and note the time at 5 minute intervals. When the
water climbs to the top of the paper, remove the paper
from the water, and let it dry.
 (NOTE: go on to other experiments while you are waiting!)
ACTIVITY
 24. Record how long it took for the water to
reach the top. Describe what happened to
the ink as the water travelled up the paper.
 25. Use the terms cohesion and adhesion to
explain capillary action.
4. Specific Heat Capacity
Write this heading in your lab notebook.
Answer questions for this section under that heading.
Vocabulary
26. Define this term as you learn
about the high specific heat of
water.
Specific heat
Specific Heat - Definition
 The specific heat of water is the amount of heat
(energy) needed to raise the temperature a
certain amount.
 Water has a high specific heat capacity because
hydrogen bonding increases interaction
between water molecules.
 It takes a lot of energy to raise 1 gram of water by
1 degree Celsius because you must break hydrogen
bonds between water molecules.
HIGH SPECIFIC HEAT
 So… Liquid water can absorb large
amounts of heat with small changes in
temperature
 So… Water heats up more slowly and
retains heat longer than surroundings
Why is this important?
This is important for many
reasons:
For instance it helps us
maintain a constant
body temperature, even
when the temperature
around us changes
HIGH HEAT OF VAPORIZATION
Vaporization (evaporation) is the change from
liquid to gas. Molecules of liquid escape and
enter air.
It takes a lot of energy to convert liquid water
into vapor because hydrogen bonds hold the
water molecules together.
ACTIVITY
 Click this link and do the activity:
 Changing Matter  Just click Increase
temperature until new text appears.
27. Describe what happens to the water molecules as you
increase the heat.
What property of water makes it able to absorb a great deal of
energy before it changes from solid to liquid to gas? (Hint:
explain what has to break to release water molecules from each
other)
Note:
• Heat is total energy (all the movements of all the particles in a substance)
• Temperature is a measure of energy (average energy of movement in a
substance) .
• As you add heat, the temperature will rise.
Evaporation
 As water evaporates, it removes heat and produces
cooling (evaporative cooling).
Many organisms take advantage of the fact that water
absorbs a great deal of energy going from liquid to
vapor state to maintain body temperature.
Sweating (people) and panting (dogs) are two ways to
prevent overheating.
Activity
 Demonstrate evaporative cooling by placing a
thermometer in room temperature water.
 Remove the thermometer and note the change in
temperature as the water on the thermometer evaporates.
28. Record the two temperatures. How would this property
of water keep you cool on a hot day? Why does sweating
cool your body down?
Ice Is Less Dense Than Water
 Water expands when it freezes (one of few substances that
does this)
 SO . . . ICE IS LESS DENSE THAN LIQUID WATER
Hydrogen bonds keep molecules “at arm’s length” when freezing
so ice floats
Density of Ice
 This is important to insulate bodies of water. Lakes freeze
from top down; allowing living things to survive in winter
when the lake freezes.
Water
Alcohol
 This blue ice cube floats
in water because ice is
less dense than liquid
water.
 The blue ice cube sinks in
alcohol because ice has a
greater density than
alcohol.
 Watch #6- Ice in my share
drive to learn why ice
floats.
 See this link to find out
Why does ice float?
Ice Density
30. Explain what would happen to fish and frogs during
the winter if ice was more dense than water.
Clean Up!
 CLEAN UP EVERYTHING ON YOUR STATION.
 DO NOT DUMP OUT THE ROOM TEMP WATER.
 WIPE UP ALL SPILLS.
 CLEAN OUT TEST TUBES AND BEAKERS.
 Detentions will be issued for groups who
cannot clean up properly.