End of Year Chemistry Talent Show Review
Problem I
Problem II
10 parts
6 parts
Problem III
Problem IV
Total
23 parts
3 parts
42 parts
Problem I: (33 pts)
Summary
 analytical chemistry using redox titration
 solutions/colligative properties
 electrochemistry
 solubility equilibria
77 pts
 little bit of everything
14 pts
 gas equilibria
156 pts
33 pts
32 pts
“Story” with data
a.
b.
c.
d.
e.
f.
Write the chemical formulas for _________ and ________. (2 pts)
Write the electron configuration for _____ as well as the _______ ion. (3 pts)
Calculate the molar concentration of the titrant solution. (3 pts)
Write the balanced equation for the reaction that occurred in the sample flask. (5 pts)
Which chemical played the role of “reducing agent” in the reaction? (2 pts)
Why does the titrant solution turn colorless when it mixes with the sample
solution? Why should the chemist stop the titration when the color stops
disappearing? (4 pts)
g. Calculate how many milligrams of _____ were in the sample. (4 pts)
h. How many milligrams would be in the whole _______? Does the ______
contain the recommended amount of ______? (3 pts)
i. What is the percent ______ by mass in the _______? (2 pts)
j. What error did the chemist make in analyzing the sample? How would this
affect the final results that she obtained? (5 pts)
Problem II: (32 pts)
A salt solution is made by dissolving ______ g of _______ in enough water to
make ______ mL of solution. All of the salt dissolves. The solution has a
density of _____ g/mL. The temperature of the solution is _____ *C. The vapor
pressure of water at _____ *C is ______ torr. The freezing point constant for
water is 1.86 *C/m. The boiling point constant is 0.512 *C/m.
a. Explain how the presence of the ions will alter the properties of the water. (6 pts)
b. Make quantitative predictions for these changes. (6 pts)
c. Name two practical applications for these alterations in properties. (4 pts)
d. The salt solution is divided into two equal samples. With one of the samples,
graphite electrodes are connected to a 9V battery and placed in the solution.
Bubbles are observed at both electrodes. At one electrode, the bubbles are
_____ and _____. Draw and label the set-up (including equations) to
demonstrate what is happening. Include the equation for the overall reaction. (6
pts)
e. Pick one of the electrodes and calculate how many grams of product will be
produced if a current of ___ A is running through the cell for __ minutes. (4 pts)
f. A sample of _____ is added to the other half of the salt solution. How many
grams of the _____ will dissolve? The Ksp for _______ is _____. (6 pts)
Cary Academy
Chemistry II
W.G. Rushin
1
Problem III: (77 pts)
Reaction Presented (suggested practice: reaction of acetic acid and ethanol to
produce ethyl acetate and water)
a. Draw Lewis Structures for all the participants in the reaction. (6 pts)
b. Draw the orbital diagram for the valence shell of a _______ atom. (2 pts)
c. Looking at your Lewis Structures and your normal orbital diagram for _______,
would it be easy to explain the types of bonds that you see the ________
engaged in? Cite one example. (3 pts)
d. Using the Hybrid Orbital Model, write the hybridized set of orbitals used by the
_________ atoms in _________ and __________ (for __________, use the
_________ in the _______ group rather than the _________ group) and the
_________ atom in the _________. Identify which type of hybridization is
occurring for each of these atoms. (6 pts)
e. Calculate the enthalpy change for this reaction using enthalpies of formation. (3 pts)
f. Calculate the enthalpy change for this reaction using bond energies. (3 pts)
g. Will the reaction release energy to the surroundings or absorb energy from the
surroundings? Which does nature prefer? (2 pts)
h. Qualitatively, predict the sign for the change in entropy for this reaction. Explain
your prediction. (3 pts)
i. Quantitatively, calculate the entropy change for this reaction. Is this change
favored by nature? (3 pts)
j. Based on the values you have calculated, predict whether this change would
be always spontaneous, spontaneous at certain conditions (identify), or never
spontaneous. (3 pts)
k. Calculate the value of the free energy change two ways. (5 pts)
l. As the reaction proceeds, what happens to the quantity of free energy? (2 pts)
m. Would the _________ molecules mix with ________ molecules? Give a
structural explanation for your answer. (4 pts)
n. What would be the molarity of __________? (2 pts)
o. Write the equation for the reaction of ______ acid in water. The reaction has an
equilibrium constant of ________. What makes hydrochloric acid different from
________ acid? (3 pts)
p. The concentrations of ______ molecules and hydronium ions are found to be
constant over time. Did the reaction stop? Explain what is happening. (3 pts)
q. Besides the addition of water and base, identify two ways to decrease the
concentration of _________ acid molecules. The reaction is exothermic. (4 pts)
r. If an __________ is dropped into ________, it bubbles and fizzes as
_________ is released. Identify 3 ways to speed up the reaction. (3 pts)
s. If the ___________ is captured in a balloon, describe what will be happening
inside the balloon. (3 pts)
t. Describe what will change if the balloon were __________. (3 pts)
u. What could be done to change the ___________ into solid? (3 pts)
v. Draw a structure and explain the forces responsible for the solid. (5 pts)
w. If the balloon is filled at room temperature (____ *C) to a volume of _____ L
with a pressure of _______, how many molecules are trapped inside? (3 pts)
Cary Academy
Chemistry II
W.G. Rushin
2
Problem IV: (14 pts)
___________ and ___________, at initial pressures of _____ and ______,
respectively, were allowed to react at 300 K. At equilibrium, the total pressure
was _________. The reaction is _________________________
a. Calculate the value of Kp. (5 pts)
b. What would be the partial pressures of all species if ____ and ____, both at an
initial partial pressure of _______, were allowed to come to equilibrium at this
temperature? (5 pts)
c. Explain the effect on the partial pressure of _____ and K p if ________. (4 pts)
Provided: AP Equation sheet and the usual reference sheets
Bring: writing instrument, calculator, & textbook (for thermo tables only)
Cary Academy
Chemistry II
W.G. Rushin
3