Assessment of Spartan AP Chemistry students (powerpoint)

Assessment of Spartan
AP Chemistry students
Julie B. Ealy
Haverford College – to be PSU
ACS – April 2001
Bond length and effect of atom size on bond length
Dipole and lack of a dipole
Bond angle and effect of atom size on bond angle
Orbitals involved in bond angles
Single, double, & triple bonds: bond length and
bond energy
Lewis dot structure, electrostatic potential surface,
and dipole
Conformation and stabilization of a molecule
Ketone, alkane, and alcohol – intermolecular forces,
molecular geometry, and hybridization
Expanded octets and hybridization
Question 1. Provide a formula for Structure 10 and
explain how Structure 10 and Structure 13 are
related by discussing the colors on the electrostatic
potential surface and providing a Lewis dot
structure for Structure 10. Be concise.
Question 2. Structure 5 has a dipole and Structure
6 does not. Explain what a dipole is and why
there is a difference in the two structures.
Question 3. On Structure 6 the bond length
between the central atom (carbon) and the atom
at the top of the structure (hydrogen) is shorter
than the bond length in a similar position on
Structure 3. Explain the difference.
Question 4. The bond angle in Structure 2 (NH3)
is approximately 107o for H-N-H. In Structure 4
which represents PH3, the H-P-H bond angle is
approximately 93o. Explain the difference in
terms of the orbitals used for bonding. It is not
necessary to draw an orbital representation, but
do explain the difference.
Question 5. Rank structures 19, 21, 23, and 24 in terms of
bond length between two carbons from shortest to
longest bond length. Also indicate the bond energy
between two carbons using the following values in
kJ/mole for structures 19, 23, and 24: 346, 615, and
825 (NOT respectively). Provide an educated estimate
for Structure 21. Provide an explanation for the C-C
bond that is the strongest.
Question 6. Structures 22 and 23 are two different
views of the same molecule. Provide an
explanation as to why Structure 23 would have
adopted the conformation it did when the
structure was minimized utilizing Spartan.
Question 7. Structures 37, 38, and 39 represent a
ketone, alkane, and alcohol. Identify each
structure by the organic group to which it
belongs. Indicate the type of intermolecular
force(s) for each organic group.
Question 8. Provide the molecular geometry and
hybridization around the atom marked with an
arrow on Structures 37, 38, and 39.
Question 9. Structures 25, 26, and 27 are all linear.
The following molecules are represented:
HgBr2, BeCl2, and XeF2. Provide two chemical
reasons how you know which structure is XeF2.
An explanation utilizing color of the atoms is
not sufficient. Which hybrid orbitals were
utilized for the xenon and how many lone pairs
are there around xenon?
Structures 25, 26, and 27 for Question 9.
Which structure is XeF2 and why?