Chemistry 31
Fall 2013
Dr. Stanton
Name ______________
Final
This exam has 7 pages, none of them blank. Use proper significant figures throughout the test.
Show all work. Please turn your cell phone ALL the way off.
Helpful Information
K = oC + 273
NAv= 6.02 x 1023
V1/T1 = V2/T2
P1V1 = P2V2
1 inch = 2.54 cm
Volume of a cylinder: V = π r2 h
Density of plutonium: 19.8 g/cm3
R
0.0821 L atm
mol K
M1V1 = M2V2
1 cm3 = 1 mL
1. (15 points) Write balanced equations for the following reactions:
a) A solution of magnesium chloride is mixed with a solution of potassium carbonate.
b) A solution of postassium hydroxide is mixed with a solution of malonic acid (H2C3H2O4.)
c) Butanol (C4H9OH) is burnt.
p. 2
Name _______________
2. (12 points) Ethane burns according to the following equation:
2 C2H6 (g) + 7 O2 (g) → 4 CO2 (g) + 6 H2O (l)
ΔH = - 3121 kJ
If an experiment is done where 7.50 kJ of heat are released, how many grams of ethane were
burnt?
3. (16 points) I have 50.00mL of 0.3022M of hydrochloric acid solution. If I have to add 29.33mL
of barium hydroxide solution in order to reach the equivalence point, what is the concentration of
the barium hydroxide solution? (barium = Ba)
p. 3
Name _______________
4. (8 points) Write ground state electronic configurations for the following. In each case, circle the
valence electrons:
a) Ca
b) Cl
5. (20 points) Short Answer:
a) What do members of a group have in common? What other elements are in the same group as
nitrogen?
b) For the 204Hg atom:
# of protons:
# of neutrons:
# of electrons:
atomic mass:
c) For 35Cl- ion:
# of protons:
# of electrons:
atomic mass:
# of neutrons:
d) I take 25.00mL of a 0.1088M solution of KOH. I add water; the final volume is 100.00mL.
What is the concentration of this new solution?
e) Draw a picture of a 2pz orbital. Explain what this picture tells you about an electron in this
orbital.
p. 4
Name _________________
6. (15 points) In August of 1994, the Natural Resources Defense Council released a report claiming that
with techniques currently available in unclassified documents, a nuclear weapon the size of the
first weapon tested by North Korea can be made with 1.0 kg of plutonium.
Suppose a smuggler is hiding plutonium in Coke cans. How many cans would be required to
carry the 1.0 kg of plutonium required for a single weapon? (This smuggler is not very smart, and
will soon be very dead. Coke cans are not good places to hide plutonium.)
Coke can dimensions: Diameter, 2.5 inches. Height, 4.75 inches.
p. 5
Name ___________
7. (20 points) Draw Lewis dot structures for the following molecules and ions, and predict the shape of
the molecule. Please make sure to draw pictures of the molecules at the end!
ClO3
-
Cl N N Cl
electron pair geometry
electron pair geometry
molecular geometry
molecular geometry
bond angle
bond angle
Draw pictures of both molecules:
8. (12 points) Jim is headed to the South Pole to work for a few months. Someone gives him a “Bon
Voyage” balloon with a volume of 7.0 L. As he leaves the Bay Area, he notices the temperature
is 12o C. He then flies to Antarctica, holding the balloon all the way. When he gets off the plane
in Antarctica, it is a typical day there with a temperature of -57oC. What will be the volume of his
balloon there?
p. 6
Name ___________
9. (20 points) 10.0 g of sodium carbonate are mixed with 50.0 mL of 3.00 M HCl solution. The gas
produced is used to inflate a balloon. What will be the volume of the balloon when the reaction is
complete? P = 0.985 atm, T = 10.0oC. (Hint: There are three products to this reaction. Two of
them are H2O and CO2. The last one you can figure out for yourself!)
p. 7
Name ____________
10. (12 points) A 1.0 cm3 cube at the center of the sun contains 190 moles of particles. If T = 1.5 x
107K, what is the pressure? (It turns out you can use the ideal gas law here, even though you
might not expect it to apply under these extreme conditions.)