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1. (16) i. Select the correct order of boiling points (low to high) for PH3'~' Ra, CH 3C0 2H and CaH 2 .
a. PH 3, CO 2 , Ra, CH 3 C0 2 H, CaH 2
b. CO 2 , Ra, PH 3 , CH 3 C0 2 H, CaH 2
i'\2..
c. CaH 2 , CO 2 , Ra, PH 3 , CH 3 C0 2 H
d. CO 2 , Ra, CaH 2 , PH 3 , CH 3C0 2 H
e. CH 3C0 2 H, PH 3 , CaH 2 , CO 2 , Ra
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ii. Which of the following is the best interpretation of the graph shown below?
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a.
b.
c.
d.
e.
This graph represents two molecules with one having stronger imfs than the other.
T 2 is higher than T, so the imfs are weaker at T 2 .
T 2 is higher than T 1 so more molecules at T 2 will have enough E to overcome imfs.
The number of molecules increases as a sample is heated.
This graph represents something that is physically impossible.
iii. To convert from ppm to ppb you should:
a. divide by 10,000
b. multiply by 10,000
c. divide by 1000
d. multiply by 1000
e. None of the above conversions will work.
C
iv. How does P vap of the solvent in any solution compare with pO vap for the solvent at the same
temPE?rature?
a. Pure solvent always has a higher vapor pressure.
b. The solvent always has a higher vapor pressure in a solution.
c. They are not related.
d. They are equal in magnitude but of opposite sign.
-A
v. Which of the following statements is true?
a. Crack has a lower vapor pressure than street cocaine.
b. Crack is cocaine that has been treated with acid.
c. The blood-brain barrier is non-polar
d. Both cocaine and crack are salts.
C
vi. Chemical equilibrium is reached when:
a. the theoretical yield is reached.
b. the concentrations of products and reactants become equal.
C. All chemical reactions cease.
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The concentrations of components are constant.
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et.
vii.
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Which of the follo~ statements is... true?
a. Porphyrins are~ar.
b. Porphyrins bind Fe 2 +.
c. Porphyrin is only produced when your body does not get enough iron.
d. Sickle cell disease is caused by a mutation in porphyrin.
viii. What is the molecular geometry of an Fe +2 Ion bound to a porphyrin. hemoglobin and carrying
either CO or 0 2 ?
a. Linear
b Trigonal planar
c Sqare planar
d. Trigonal bipyramldal
e. Octahedral
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2 (4) Sketch InP vap vs 1fT (in Kelvin) for water on the graph below Predict both the sign and
magnitude of the slope of the line.
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In
/to
slope = _ _----L~-"-
PV3P
1fT
r- Kb = 10 -'1.7'/
3. (15) pK b of ammonia is 4 74
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't
=' ,.
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What concentration of ammonium chloride has a pH of 6 2?
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-'03-/0.1 -
0
,.3t./o""
'.3,.10....,
x . fl. 3 t/O~
Y.':;:: 1.,51-IO~M
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Rank 1M aqueous solutions of the following salts from low pH (left) to high pH right
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4. (10) Give a chemical concept, principle, or a brief statement to explain the following situations:
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a. Pasta is cooked in salted water.
1 b.p.
b. Primitive cultures preserved meat by smoking or salt-curing.
c.
Antacids commonly contain CaC0 3
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d.
Baking times are different at high altitudes.
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e. The pH of a bottle of Coke is lower when newly opened than when it is allowed to "go flat".
COS- ~es
~ tl-a.c./cJ.ic..
~~/MDI
'f"~/mol
5. (14) At 35°C the Pvap of the non-ionic volatile liquids methanol (CH 3 0H) and ethanol (CH 3 CH 2 0H)
are, respectively, 94mm and 44 mm.
• Find the vapor pressure of a solution made by mixing equal masses of each. - ~.c.k
m4.55
• Find the mole fraction of each in the vapor above the'·solution.
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p+Ot- -
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of
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lq mol ~csl- )
t~. &oJ ~...
t
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11. OS" ~ 13. c.I i
5S. tl 3
oH
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=
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6. (13) Hexabarbital is a non-electrolyte sedative and intravenous anesthetic that is 61.00%C, 6.83%H,
11.86%N and the rest oxygen by mass. A 2.505 mg sample of hexabarbital in 10 mL solution at 25
°c has an osmotic pressure of 19.7 mm Hg. Determine the molecular formula of hexbarbital.
:;. O.,Ll7/'l3
_ (. a''r", 7S'
~
1l'~
MJ<.T
Iq.l""",,, la.tm
740drA
M'==
-= M (.082 l1;K\ • aq~ K
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O.OOI~ol
o.ooKtMol
L
L
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01 L
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= l.~ IO-~t\"\ol IV'\OlG\lMC4St~ =.~
1.1.'rr:~
63~.~q~
7. (13) Acetic acid tends to form dimers due to hydrogen bonding: 2 CH 3C0 2H H C2H6C204H2
2
The equilibrium constant (Kc ) for this reaction is 1.51 x 10 in benzene (C 6H6) solution and 3.7 x 10-2 in
aqueous solution.
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• Explain this difference. - i~ ~Ol •.,. c~ oJso ~ band ..,/ S)lv~. No\- It" uc.n~
• Calculate the ratio of dimers to monomers in water if the concentration of acetic acid initially
is 2M.
(t!J
~C~CCQ~
<
flJ
.. Ca\1c.C... Ci,l-I~
~~
0
-~,.
)(
k ~,.:)hIOA =
X
(a·~)(
)
~
....
'I. -; .03t4
X
'-/_ ";y,
2
+
4 y.

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