Chemistry 161
Exam 2, June 2nd, 2010
Name: ____________________
Show all work for full credit
Exam #2 – Structure and Stoichiometry
SHOW ALL OF YOUR WORK TO RECEIVE
FULL CREDIT
Make a note of the point value of each question, and allocate your time accordingly.
Carefully read each question.
Where appropriate, work must be shown to receive proper credit.
Take your time, make sure to check your work for mistakes when you are finished.
Partial credit will be awarded based on work shown.
If you get stuck, move on to another problem.
Use a pencil so that you can erase any mistakes.
Page
Points
2
40
3
22
4
38
TOTAL
100
Score
1/4
Chemistry 161
Exam 2, June 2nd, 2010
1. (40 points)
Chemical
Formula
Name: ____________________
Show all work for full credit
Draw the Lewis Dot Structure
(Include ALL lone pair electrons
and RESONANCE structures)
Is the compound
polar? If yes, draw
the net dipole
Molecular
Geometry
And
Electron
Geometry
Shape:
PO23Electron
Geometry:
Shape:
XeCl4
Electron
geometry:
Shape:
SeO3
Electron
Geometry:
Shape:
IBr3
Electron
Geometry:
2/4
What are
the Bond
Angles?
(X-A-X)
What is the
Hybridization
state of the
central atom?
Chemistry 161
Name: ____________________
nd
Exam 2, June 2 , 2010
Show all work for full credit
2. a. (10) The bonding in the diatomic molecule C2 can be explained using molecular orbital theory.
Draw an energy diagram that represents the molecular orbitals created when the C2 molecule is
formed, and fill in these orbitals with the appropriate number of electrons.
(label your orbitals for full credit)
b. (2) What is the bond order of this molecule?
c. (2) What can you say about the magnetic properties of the C2 molecule?
3. (8) Answer questions about the following molecule:
..
..
..
a
..
a. (2) How many sigma bonds does this molecule have? (Be careful!)
_______
b. (3) How many pi bonds does this molecule have?
Circle each of these pi bonds for full credit.
_______
c. (1.5) What is the hybridization state of the carbon labeled with an “a”? _______
d. (1.5) What is the formal charge of the terminal nitrogen (right one)?
3/4
_______
Chemistry 161
Name: ____________________
nd
Exam 2, June 2 , 2010
Show all work for full credit
4. (11) Fill in any blanks in the following table (for instance, give the formula if the name is given):
Compound Formula Covalent or Ionic?
Name of compound
CO
SrCl2
CrO
Ammonium sulfite
Cu2O
PO4
Vanadium (II) Nitride
5. (27) 382.33 grams of ammonia react with 751.35 grams of oxygen gas in the following balanced
reaction:
2NH3 (g) + 3O2 (g)
N2O3 (g) + 3H2O (g)
a) (7 points) Determine the limiting reagent
b) (7 points) Calculate the theoretical yield of dinitrogen trioxide produced (in grams).
c) (8 points) Calculate the moles of unreacted reactant.
d) (5 points) My lab typically has a 47.3% yield for the above reaction. What will my actual yield
be for this reaction given the reactant quantities indicated above (in grams).
4/4