Macroscopic Observations
Clear
Cold
Solid
It melted as we
watched
No smell
Micromodels
Click on the link to go to an interactive
ice molecule. Right below on the same
linked page there is also an interactive
liquid water molecule. The red balls
are oxygen(O) and the white ones are
hydrogen(H). Water/ice has polar
covalent bonds. Each water molecule is
connected to another one through
Hydrogen bonds. Notice that the ice
molecules are spaced out further than
the water. That is why ice is less dense
and floats in water.
http://www.worldofmolecules.com/interactive_molecules/ice.htm
These molecules were created with the Jmol App and are a part
of the “World of Molecules” website which can be found with
this link.
Macroscopic
Observations
Micromodels
This link goes to an interactive
molecule of iodine. The purple is
iodine molecules. They have
nonpolar covalent bonds.
Turned the paper
yellow
Shiny-has luster
http://www.creativeThe yellow went
chemistry.org.uk/molecules/structures.htm
through the paper
Room temperature This link shows iodine in the process of
Turned blue in the
sublimating. Sublimation is when the
iodine goes from a solid straight to a gas.
water/ice
This linked model was
creqted with Chem
Axon Ltd for the
“Creative Chemistry”
website. ©2000-2009
This occurred when the iodine gave off a
yellow color that appeared on and through
the paper.
This linked model is
part of the “Tutor Vista”
website. ©2008
http://image.tutorvista.com/content/mattersurroundings/subliimation-at-submicroscopic-level.jpeg
Macroscopic Observations
Tastes salty
Very hard
Clear
Room temperature
Melted the ice when it
came into contact
Doesn’t react with
iodine
Micromodels
Click on the link below to view an
interactive salt molecule. The
purple is sodium(Na) and the green
is chlorine(Cl). Salt has ionic bonds.
A salt molecule can’t have
This molecule was created
hydrogen bonds because it doesn’t
with the Jmol App and is
contain Oxygen, Nitrogen, or
part of the “World of
Fluorine.
Molecules” website.
http://www.worldofmolecules.com/interactive_molecules/salt.htm
©1999
•How does Iodine turn the paper yellow?
•Why does Iodine turn blue with water?
•How does salt melt ice?
Macroscopic Observations
Static electricity
pulled the water
toward itself
The balloon had to
be pretty close before
it attracted the water
This model is part of the
“Science by Email”
website
Micromodels
Click on the link below to go to a picture
that shows why the balloon pulled the
water toward itself. You will see a
negatively charged balloon(when you
rubbed the balloon on your hair you gave
the balloon electrons or static electricity.
This attracts the positive ends of the
water molecules and makes them align.
The positive parts of the water molecules
are hydrogen and the negative is oxygen.
This is a good example of intermolecular
forces. One thing it doesn’t show is that
before the water molecules get close to
the balloon they aren’t aligned.
http://www.csiro.au/helix/sciencemail/activities/images/Wat
erBendMolecules.gif
Macroscopic Observations
Static electricity pulled
ethanol toward itself
Had a slightly stronger
reaction than water
Smelled like gas
Micromodels
This is a model of static electricity attracting
ethanol. The balloon shown is negatively
charged after being rubbed on someone’s hair.
The nonpolar ethanol has a positve end so it is
attracted to its opposite. This makes the
molecules align with the balloon and change the
water current. The red is oxygen, the greens are
carbon, and the others are hydrogen for the
ethanol.
The ethanol molecules are from “The Interactive Library” at
Edinformatics.com and the balloon is from the “Science by
Email” website.
Macroscopic Observations
No reaction
Splashes on the counter
evaporated quickly
Micromodels
This model shows that
hexane does not react to
the negatively charged
balloon. Hexane is
nonpolar so it doesn’t have
opposite ends(positive and
negative). This means that
nothing will be attracted to
the balloons electrons and
so the hexane won’t align
with them. Since nothing
attracts, the flow of hexane
doesn’t change.
The hexane molecules
were created by Ben Millis
and were found on
“Wikimedia Commons.”
The balloon was found on
“Science by Email.”
What is being aligned?
Why doesn’t some
water/ethanol get pushed
away from the balloon even
though there is also a
negative side to the
molecule?
Macroscopic Observations
Evaporated pretty
quickly on glass
Evaporated slowly on
plastic
2 drops for the
microspatula
Easy to pull glass apart
Easy to pull plastic
apart
Micromodels
Ethyl alcohol evaporates a little slower than acetone but
faster than water. Ethyl alcohol can cohere and adhere much
better than acetone but not as well as water. Hydrogen
bonds form between hydrogen and oxygen on the glass so
that adheres. Ethyl alcohol has oxygen in it so that makes it
able to cohere but because of its structure it doesn’t have as
strong of a cohesion as water. Since it doesn’t hold itself
together as well it separates and then evaporates. The black
lines are bonds and the red is oxygen.
Plastic
Glass
Macroscopic Observations
Didn’t evaporate while
we watched
2mm height on glass
10mm width on glass
2.5mm height on plastic
5mm width on plastic
3 drops for microspatula
Easy to pull apart on
plastic
Kind of hard to pull
apart glass
Micromodels
These models show why water didn’t evaporate as fast
as the other two did. The green lines within the water
droplet are hydrogen bonds that hold water molecules
together. That is called cohesion. Water also forms a
bond with the plastic which is called adhesion. The
hydrogen in the water forms a hydrogen bond with the
oxygen in the glass. Since everything is bonded together
it takes a lot longer to break them apart and for the
water to evaporate. The black lines are also hydrogen
bonds. The red on the glass is oxygen.
Plastic
Plastic
Glass
Glass
Macroscopic Observations
oEvaporated the
quickest of the three
oEvaporated a little
quicker on plastic than
on glass
o2 drops for the
microspatula
oHard to pull glass
apart
oEasy to pull plastic
apart
Micromodels
Acetone evaporates quickly because it can’t cohere. It can
adhere to other things with hydrogen bonds but since it
doesn’t bond with itself it can’t hold itself together and avoid
evaporation. The hydrogen in acetone can form a hydrogen
bond with the oxygen in glass but there is nothing for it to
bond with in plastic. This makes it evaporate faster on
plastic. The black lines are hydrogen bonds between the
white hydrogen and the red oxygen. The green is carbon and
the red in acetone is oxygen.
Plastic
Plastic
Glass
Why does acetone evaporate so quickly?
Why can’t acetone cohere?
Why did the alcohol evaporate almost as
quickly as the acetone if it bonds a lot better?
Micromodels
This model shows the boiling of water. When
heat or energy is applied to the bottom it
starts to make the molecules move. More
and more start to move from the bottom up
until it is boiling. The bubbles are just pockets
of water vapor that formed after molecules
split far enough apart from each other. Since
they are less dense they rise to the surface
and then break through.
Purple=oxygen
White=hydrogen
Macroscopic Observations
Little bubbles form on the
bottom and then break off
and rise
Bubbles stop at surface for a
little bit before breaking
through
More steam appears when
there are more bubbles
Some bubbles rise straight
up and others zigzag
After awhile bubbles start to
appear on the side too
Some bubbles got halfway
through surface but got stuck
for awhile
This is a model created by Charles E.
Ophardt from Elmhurst College for the
college’s online “Virtual ChemBook.”
©2003
Macroscopic Observations
Bubbles came mainly
from the penny
Penny shook a lot
It created a nucleation
site
Bubbles were larger
than before
Red/purple=oxygen
white=hydrogen
Micromodels
This is a model of what
happened when we dropped
the penny into the boiling
water. It created a
nucleation site in the beaker
which allowed many bubbles
to form on the penny. A
nucleation site is just an area
with many holes or rough
spots that bubbles can form
in. Since there are so many
rough spots on a penny
there were a lot of bubbles
forming there.
Why do some bubbles go straight up and
others zigzag?
Why did some bubbles get stuck at the
surface for awhile and others went through
quickly?
Why did some bubbles form on the side
instead of the bottom later on?