What do Lady and the Tramp and Bromine and Cyclohexane Have in Common?
When you are in love, you would rather spend time with that
someone who likes spaghetti as much as you do.
So far, we have explored properties like pH, conductivity and solubility as part of our strategy for attempting
to understand how the periodic table works. We’ve discovered that the patterns we have seen in our
previous explorations can be explained by the major trends we see in the periodic table; particularly
ionization energy and electronegativity. Increasing reactivity as you proceed down the alkali metals, the
differences between the conductivities of calcium and magnesium hydroxide compounds, The trends we
see in solubilities when we observe double replacement reactions, and the degrees to which halogens will
react with halide salts…all these patterns appear to be related to positioning on the periodic table.
There still is one issue, one little head-scratcher, that confounds us; something that occurred when we were
examining single replacement reaction in the presence of cyclohexane.
[place the little ‘head-scratcher here’]
Once Upon a Time There was a Test-Tube
“How about a short summary
of what we talked about in
class.”
The question we need to ask is’ “What do bromine, cyclohexane, and water have to do with Lady and the
Tramp eating spaghetti?”
Here are a number of little exercises to help get your ‘little gray cells’ charged up. And it will only cost
you a penny.
1. How many drops of water can dance on the head of a penny?
a. Before beginning your ‘drop test’, make a prediction addressing the number of drops of
water you can collect on the top of a penny without any water falling over the edges of the
coin.
b. Drop water on the ‘head’ side of the penny using a hand pipet. Count the maximum number
of drops you can collect on the coin. How close did you come to your prediction?
c. Dry off the penny. Dip a toothpick into a detergent and rub it on the surface of the penny.
d. Drop water on the penny again, counting the drops until the water overflows.
2. Then there is the One about Water Playing ‘Slip and Slide on Glass and Wax Paper.
a. Place a few drops of water on a glass slide
b. Slide a toothpick through the water and see what happens.
c. Now add a drop of detergent to the water. Slide the toothpick through the water and see
what happens.
d. Record your observations
e. Repeat steps a-d using a small strip of wax paper instead of a slide. What happened?
3. …And then discovering that paperclips float. Who Knew?
a. Take a deep breath and carefully set a dry paperclip on the surface of a petri dish full of
water.
b. Add detergent to the water. Record what you observe.
4. …Like a circle in a spiral, like a wheel within a wheel.
a. Repeat steps 1-3 using isopropyl alcohol, Canola Oil, and Cyclohexcane. Make sure you
work with the cyclohexane under the chemical hood; probably the alcohol as well. Wash
your hands with soap and water when you are finished.
b. Perhaps, if you have not already taken the time to do this, you might do some background
research to help explain your observations so far.
Can you explain why things happened the way they did because it’s only
going to get messier?
Bet you can’t do it!!
Have a Cigar…
5. …Never ending or beginning on an ever spinning wheel
a. Using a scoopula, place a grain-of-rice sized sample of the following chemical compounds
into the designated wells on a drop plate as follows. If drop plates are not available, use
testest tubes and add approximately a mL of distilled water:







benzoic acid in wells A1–A3
magnesium chloride in wells B1–B3
stearic acid in wells C1–C3
sugar in wells D1–D3
Copper (II) chloride in wells E1-E3
Zinc chloride in wells F1-F3
Sodium chloride in wells G1-G3
b. Add several drops of testing liquids to each well in a vertical column, as follows:



distilled water wells A1–D1
methanol to wells A2–D2
cyclohexane to wells A3–D3
c. Record results on the following table. If the two materials in the well dissolve indicate with
(+), if not (-).
Substance
Benzoic Acid
Magnesium
Chloride
Stearic Acid
Sugar
Copper (II)
Chloride
Zinc Chloride
Sodium
Chloride
Chemical
Formula
Volatility
+, -
Melting
Point
Dissolves in
water
Dissolves in
Methanol
Dissolves
in hexane
Conductivity
6. …And the world is like an apple whirling silently in space.
Can you look at the results and make sense of this mess?
What does this have to do with Lady and the Tramp…
Well, now what are we
going to do?
Now it’s you turn:
And What about‘Stinky Moe’?
Why won’t he go away? Why
does he keep sticking his stinky cigar in our business?