Name____________________________________________________Date_________________
Predicting Solubility
The Science of Spot Removers
Mrs. Foley
_________________ ran into __________________ with an open
sharpie marker, leaving a big ugly mark down the front of
_____________________white shirt. “Oh no,” cried
____________________, “that stuff is
PERMANENT.”
Your Objective-Help your classmate figure out how to dissolve sharpie marker from
their now ugly shirt. You should also figure out a general rule to predict whether or
not two substances will dissolve and form a solution.
What you need to know: The answer to the problem has a lot to do with the polarity
of molecules (reminder-molecules are covalently bonded).
Materials
1.
2.
3.
4.
5.
6.
7.
8.
Goggles
dropper bottle with hexane
water
cotton tip swabs
glass square
wax (glass) crayon
vis a vis marker
ceramic spot plate
Disposal Alert !!!!
Safety CheckList Please initial each before beginning the lab. Failure to do so will
result in a zero.
__________ Goggles are on and long hair is secured
__________Hexane is toxic and must not be spilled. In case of an accident, flush with
water right away.
__________ Cotton tip swabs dipped in hexane must be placed into the waste cup
provided and returned to the back counter at the end of the lab.
Let’s review the polarity of the liquids that you will work with today.
1. Water
Polarity________________________
Because________________________
2. Hexane
Polarity_________________________
Because _________________________
3. Wax Crayons = __________________________
4. Vis a Vis marker = _______________________
Procedure
1. Read and initial all safety precautions.
2. Most of your supplies are at your lab station, obtain any other supplies that
your teacher indicates.
3. Hexane is in a dropper bottle at your lab station and must be handled with
care.
4. Clean and dry a glass square and place it on a white piece of paper at your
station.
5. Use the wax crayon and vis a vis
marker and mark the square as
shown.
6. Use a pipette to place 3 drops of
water into a depression on the ceramic spot plate. Dip a swab into the water
and lightly
touch one small section of the wax crayon. Lightly wipe one section of the wax
crayon 3 or 4 times and note if any of it dissolves off into the water. Repeat
with one section of the vis a vis mark. Record soluble (dissolved in water) or
insoluble (did not dissolve in water) on your table. Place used swabs onto a
paper towel to be discarded later.
7. Place 3 drops of hexane into a well on your spot plate. Handle bottle carefully
and secure the top on the dropper bottle when finished. Dip a swab into a
little hexane and test one section of the wax crayon to see if it dissolves.
Repeat with the vis a vis marker. Place the cotton swabs into the waste cup
for your teacher to dispose of. Record your results in your data table.
Clean up!!
8. Wipe off your glass square to remove any leftover wax crayon/ marker.
Then wash the glass square with soap, rinse well and dry with a paper towel.
9. Wipe the spot plate with a wet paper towel and dry. If you have any hexane left
in the spot plate use a cotton swab to soak it up and place the swab in the
disposal cup. Should skin contact occur rinse with water and call your
teacher.
10. Bring your cup of used cotton swabs to the back counter.
11. Wash your counters, then wash your hands, degoggle.
Observations
Record soluble (does dissolve) or insoluble (does not dissolve) in pencil.
Substance
Water
Hexane
Wax Crayon (glass writer)
Vis a Vis marker
Discussion (answer in pen below each question).
1. Write the polarity of each substance next to its name in the data table.
Which substance dissolved in water? How does the polarity of this substance
compare to water’s polarity?
2. Which substance dissolved in hexane? How does the polarity of this substance
compare to hexane’s polarity?
3. Based upon your answers to questions 1 and 2, come up with a general rule
for predicting when two substances will dissolve in one another. Base your
rule on polarity.
4. Black sharpie marker cannot be removed with water. What does this suggest
about the polarity of black sharpie marker?
5. How could we get black sharpie marker off a white shirt?
6. Explain why oil and water do not form a solution.
7. Explain why the white bear dissolved in water.