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Chemical Bonding Study Guide
Level 2 Questions
Vocabulary: For the following key terms, use your notes/previous assignments to write a definition IN YOUR OWN
WORDS. Then, draw a picture or diagram to help you remember the word and why it is important.
Chemical bond
Van der Waal force
Hydrogen Bond
Ionic Bond
Covalent Bond
Instantaneous dipole
Induced dipole
Noble Gas
Intermolecular Force
Intramolecular Force
Electronegativity
Cohesion
Adhesion
Polar/ Polarity
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Practice Level 3 Questions
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1. For A-D, state what type of bond most likely holds the molecule together. Then, explain why.
A. HCl
Covalent bond—this is an intramolecular bond that holds 2 nonmetals together. H and Cl are both
nonmetals. The bond will form because the atoms have similar electronegativities, so neither one has a
strong enough pull to steal electrons from the other. Instead, they must share electrons, which forms the
bond.
B. NaCl
Ionic bond—This is an intramolecular force that holds a metal and a nonmetal together. Na is a metal, and Cl
is a nonmetal. The bond will form because Cl is much more electronegative than Na, so it will steal Na’s 1
valence electron. Once the electron is stolen, Na will have a +1 charge, and Cl will have a -1 charge. The
opposite charges will attract to form the bond.
C.
(Explain all bonds)
The intramolecular forces that make up each individual water molecule are covalent bonds. The dashed line shows an
intermolecular hydrogen bond, which connects 2 whole water molecules together. The hydrogen bond forms because O
is much more electronegative than H. So, H’s one valence electron spends more time on the O side of the atom, and
forms the bond.
This is a Van der Waal force. A negative partial charge (dipole) is attracting a positive partial charge (dipole). This
happens when all of the electrons randomly move to one side of the atom to create an instantaneous dipole. Then, a
second atom creates an induced dipole to bond to it. (You can narrow down not ionic bond because no net charge, not
covalent because no electrons shared, not hydrogen bond because they all have more than 1 electron and cannot be
hydrogen.)
2. Explain how a particle’s polarity and bonding properties are used in ink chromatography.
Polar particles have stronger partial charges and are able to form stronger hydrogen bonds to the paper towel
(stationary phase). This means that polar particles do not travel as far up the paper towel and will stick close to the
bottom.
3. Draw a sketch of the lab setup for the ink chromatography lab. Label all materials and glassware (with size in
mL). Label the mobile phase. Label the stationary phase. Label where cohesion and adhesion are occurring.
Would particles with a high Rf value travel far up the paper, or stick closer to the bottom? Explain why.
Mobile phase= water/acetone mixture
Stationary Phase= paper towel
High Rf values travel further, because Rf is a ratio of distance particle travelled/ distance liquid travelled
Drawing:
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4. Explain why you can fill water above the rim of its container without the water spilling.
Water is highly cohesive, so it has a tendency to stick to itself, rather than other particles. Water hydrogen
bonds to itself, so the particles above the rim of the container bond to the ones inside the container.
Level 4 Questions:
5. Which compound would you expect to have a higher boiling point— H2O, or HF? Explain why. (Hint: Think about
the types of bonds and number of bonds each molecule can form.)
HF is made with one hydrogen bond. H2O is made with 2 covalent bonds (and hydrogen bonds, if there are
multiple molecules are connected). Since covalent bonds are stronger than hydrogen bonds, they are harder to
break (require more heat to break). So, water would have a higher boiling point.
6. What type of chemical bond is responsible for the attachment of antibodies to foreign antigens in human blood?
What might happen if these bonds were not present in blood?
Van der Waal forces—If there were no Van der Waal forces in the blood, there would be no way for antibodies
to bind foreign antigens. This means that we would not be able to attack foreign blood types/ foreign particles.
We would likely get sick from contaminants.
7. Draw a chain of chemically bound molecules that contains two intermolecular forces and eight intramolecular
forces. Label all elements in each molecule. Label all bonds as inter/intramolecular, and then state what specific
type of bond they are.
Answers will vary—should show 3 molecules bound together.