Investigating the Effects of Polarity
Name __________________________
Block _____ Date ________________
Purpose:
The purpose of this experiment is to investigate the solubility of ionic, polar and
non-polar compounds in a variety of solvents.
Pre-lab Questions:
1. What do the words “miscible” and “immiscible” mean? Look them up
using a text book, computer, or smart phone.
2. What is a solvent?
3. What is a solute?
4. What does the term “solubility” mean?
5. Draw the Lewis dot structures for Water (H2O), Ethanol
(CH3CH2OH), and Hexane (C6H14). Using your knowledge of polarity,
label each of them as being ionic, polar covalent or non-polar covalent.
6. Determine if Potassium Nitrate (KNO3) is ionic, polar covalent or non-polar covalent
by drawing its Lewis dot structure – it’s a bit tricky.
7. Determine if Methanol (CH3OH) is ionic, polar covalent or non-polar covalent by
drawing its Lewis dot structure.
8. Determine if Iodine is ionic, polar covalent or non-polar covalent by drawing its Lewis
dot structure.
Safety:
 Ethanol, methanol, and hexane are flammable organic solvents and dangerous
fire risks. Keep away from flames.
 Ethanol is poisonous – do not ingest. Avoid breathing vapors from all of the
chemicals used in this lab.
 Iodine is toxic by ingestion or inhalation. It is a skin and eye irritant and will stain
skin and clothing.
 Avoid contact of all chemicals with eyes and skin. Wear goggles at all times
during this lab! Wash your hands immediately after chemical contact and before
you leave lab.
Procedure:
For this lab, you will be mixing multiple chemicals together to observe their relative
solubility. Be sure to carefully label all of your glassware, or to make yourself a key, so
that you know what glassware contains what chemicals as many of these substances
are identical in appearance.
Part 1. Solubility in Hexane
1. Obtain five (5) clean test tubes. Label them #1-5 with chem tape from the center
island.
2. Add about 2 mL (1/3 full) of the appropriate solvent (hexane) to each test tube using
the eyedropper.
3. Using a scoopula, eye dropper, or transfer pipette, add a small amount of the
appropriate solute (shown in Table 1) to each test tube. Record your observations in
Table 1 while you gently swirl each test tube to mix the solute and solvent. Finish your
observations on the first test tube before moving on to the next.
***Observations are our only source of data in this lab! Make yours as accurate and
descriptive as possible!***
Part 2. Solubility in Water
1. Obtain five (5) clean test tubes. Label them #1-5 with chem tape from the center
island.
2. Add about 2 mL (1/3 full) of the appropriate solvent (water) to each test tube using
the eyedropper.
3. Using a scoopula, eye dropper, or transfer pipette, add a small amount of the
appropriate solute (shown in Table 2) to each test tube. Record your observations in
Table 2 while you gently swirl each test tube to mix the solute and solvent. Finish your
observations on the first test tube before moving on to the next.
Table 1: Hexane Solubility
Test
Tube
Solvent
1
Hexane
Water
(1 mL)
2
Hexane
Ethanol
(1 mL)
3
Hexane
Iodine
(1 crystal)
4
Hexane
Methanol
(1 mL)
5
Hexane
Potassium
Nitrate
(pea-sized
scoop)
Notes:
Polar or
Non-Polar?
Solute
Polar or
NonPolar?
Observations on Solubility
Table 2: Water Solubility
Test
Tube
Solvent
1
Water
Hexane
(1 mL)
2
Water
Ethanol
(1 mL)
3
Water
Iodine
(1 crystal)
4
Water
Methanol
(1 mL)
5
Water
Potassium
Nitrate
(pea-sized
scoop)
Notes:
Polar or
Non-Polar?
Solute
Polar or
NonPolar?
Observations on Solubility
Post Lab Questions
1. The two solvents you used in this lab are water and hexane. Using your Lewis Dot
diagrams for each, place water, hexane, and ethanol in order from most non-polar to
most polar. Explain why this is.
2. Look back at your prelab questions regarding the polarity of each solvent and solute.
Now look at your observations on the solubility of each solvent and solute. Do you
notice any patterns about what types of solvents dissolve what types of solutes? You
should!
3. List all of your solvents and solutes in approximate order of polarity, from most polar
to least polar. Provide a brief explanation on how you decided on the order, using lab
observations to support your conclusions.
Most Polar
Least Polar
4. Summarize your findings from Parts 1 and 2 in two statements.
_______________ substances are soluble in ______________ substances, but are
insoluble in _______________ substances.
_______________ substances are soluble in ______________ substances, but are
insoluble in _______________ substances.
5. Blood is mainly composed of water. Using this information and your results from
Part 2, would cholesterol be soluble in the bloodstream? Why is this a problem?
Hint: All of the corners of the hexagons and pentagons are carbon atoms with 1 or 2
hydrogen atoms bound to them.
6. Would you predict vitamin A or vitamin C to be soluble in water? Why?
Vitamin A
Vitamin C
7. Revisit your definition of solubility. What properties of the solvents and solutes allow
them to dissolve in one another? (Hint 1: Is dissolving a physical or chemical change?
Hint 2: Think about what has to happen for a molecule to “dissolve” another molecule)
8. Draw two diagrams showing how water dissolves methanol and how it would dissolve
NaCl.