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1
Chem. 1C Final Practice Test 2
Name__________________________________________
Perm Number __________________________________
All work must be shown on the exam for partial credit. Points will be taken off for incorrect or
missing units. Calculators are allowed. Cell phones may not be used for calculators. On
fundamental and challenge problems you must show your work in order to receive credit for the
problem. If your cell phone goes off during the exam you will have your exam removed
from you.
Fundamentals (of 72 possible)
Problem 1 (of 18 possible)
Problem 2 (of 16 possible)
Problem 3 (of 10 possible)
Problem 4 (of 24 possible)
Multiple Choice (of 60 possible)
Final Total (of 200 possible)
First letter
of last name
2
Fundamental Questions Each of these fundamental chemistry questions is worth 6 points. You must show work to get
credit. Little to no partial credit will be rewarded. Make sure to include the correct units on your
answers.
1) 6 pts Consider the structure of mimosine shown below.
What functional groups are present? Circle the functional groups present in
mimosine.
aldehyde alcohol tertiary tertiary amine carboxylic acid
secondary amine ketone primary amine ester
2) 6 pts [Fe(H2O)6]3+ absorbs light =700. nm. What is the value (in ππ½
πππ) of Ξo and
what color will the complex appear?
βπ=βπ
π=
(6.626 Γ 10β34 π½ β π )(2.99 Γ 108 ππ )
700.Γ 10β9 π= 2.83 Γ 10β19 π½
(2.83 Γ 10β19 π½
πβππ‘ππ) (
6.02214Γ1023 πβππ‘πππ
1 πππ) (
1 ππ½
1000 π½) = 170.
ππ½
πππ
700 nm is in the red region of the spectrum. Therefore, the complex is
green.
3) 6 pts Draw or name each of the following:
5-methyl-2-hexyne
3-bromo-7-propylcycloheptene 2,6-dimethyloctane
Br
3
4) 6 pts Draw all of the structural isomers for C6H14. Circle those that can be
geometric isomers.
None of these can be geometric isomer. You must have a double bond to
have geometric isomers
5) 6 pts
Which has the highest boiling point: HCl HF HBr
Which has the lowest melting point: C3H8 CH3OH
Which has the greatest surface tension: N2(l) Br2(l)
At room temperature each of the following organic molecules has a different
phase. Match the molecule to the phase.
Hexane Solid
Propane Liquid
Dodecane Gas
6a) 4 pts A new substance developed in a laboratory has the following properties:
normal melting 83.7ΛC; normal boiling point, 177ΛC; triple point 200. torr
and 38.6ΛC. Sketch the approximate phase diagram and label the solid,
liquid, and gaseous phases.
6b) 2 pts Based on your drawing is the solid or liquid more dense?
Solid is more dense because when you increase pressure you transition
from liquid to solid.
4
7) 6 pts A freshly isolated sample of 90Y was found to have an activity of
9.8Γ105 disintegrations per minute at 1:00 pm on December 3, 2000. At
2:15 pm on December 17, 2000, its activity was redetermined and found to
be 2.6Γ104 disintegrations per minute. Calculate the half-life of 90Y.
ππ(π) = βππ‘ + ππ(ππ) Determine t:
Amount of time between readings
14 full days + 1 hour + 15 minutes
Convert to min:
14 π(24 βπ
1 π)(60 π
1 βπ) + 1 βπ(60 π
1 βπ) + 15 π = 20,235 π
ππ(2.6 Γ 104) = βπ(20,235 π) + ππ(9.8 Γ 105)
π = 1.79 Γ 10β4 1
π
π‘12β =
ππ(2)
π=
ππ(2)
1.79 Γ 10β4 1π
= 3,864 π = 2.7 π
8) 5 pts The following data was collected for the reaction
A + B C + D Ea=161 ππ½
πππ
k=1.94Γ10-4 πΏ
πππβπ at 30.0Β°C
What is k at 40.0Β°C?
ππ (π2
π1) =
πΈπ
π (
1
π1β
1
π2)
ππ (π2
1.94 Γ 10β4 πΏπππβπ
) =161,000 π½
πππ
8.3145 π½πππβπΎ
(1
303.2πΎβ
1
313.2πΎ)
π2 = 0.00149 πΏ
πππβπ
9) 6 pts What is the freezing point of 2.0 g of CaCl2 dissolved in 1.0 L of water?
ππ»2π = 1.0 π
ππ
Ξππ = πππΎπ
i=3 Calculate m
π =ππ πππ’π‘π
ππ πππ£πππ‘
ππ πππ’π‘π = 2.0 π πΆππΆπ2 (1 πππ πΆππΆπ2
110.984 π πΆππΆπ2) = 0.018 πππ πΆππΆπ2
ππ πππ£πππ‘ = 1.0 πΏ (1000 ππΏ
1 πΏ) (
1 ππΏ
1 ππ3) (1 ππ3
1 π) = 1000 π
π =0.018 πππ
1.0 ππ= 0.018 π
βππ = (3)(0.018 π) (1.86 ββππ
πππ) = 0.100β
ππ = 0β β 0.100β = β0.100β
5
10) 6 pts Calculate the binding energy per nucleon ( π½
ππ’πππππ) for 62Ni
(π62ππ= 61.928 π’)
Ebind = Ξmc2
28 π»11 +34 π0
1 ππ2862
Ξm = π62ππβ (28π1π»
+ 34ππ)
Ξm =61.928u β ((28(1.0078u)) + (34(1.0087u))) = -0.5862u
Convert mass to kg
β0.5862π’ (1.6605Γ10β27ππ
1π’) = β9.760 Γ 10β28ππ
πΈππππ = (9.760 Γ 10β28ππ)(2.9979 Γ 108π
π )
2= 8.77 Γ 10β11π½
(8.77Γ10β11 π½
62 ππ’ππππππ ) = 1.41 Γ 10β12 π½
ππ’πππππ
11a) 3 pts The carbon-14 nuclide radioactively decays by beta emission. Write a
balanced nuclear chemical equation that describes this process.
πΆ614 β πβ1
0 + π714
11b) 3 pts The tungsten-180 nuclide radioactively decays by alpha emission. Write a
balanced nuclear chemical equation that describes this process.
π74180 β π»π2
4 + π»π72176
12) 5 pts Determine the rate law from the following mechanism.
H2S β H+ + HS- fast equilibrium
Cl2 + HS- H+ + 2Cl- + S slow
Indicate if the reaction contains intermediates or catalysts and which
substances they are.
There are no catalysts and HS- is an intermediate
Rate= k2[Cl2][HS-]
Eliminate the intermediate
k1[H2S]=k-1[H+][HS-]
[π»πβ] =π1
πβ1
[π»2π]
[π»+]
π ππ‘π =π2π1
πβ1
[πΆπ2][π»2π]
[π»+]
6
Challenge Problems Each of the following short answer questions are worth the noted points. Partial credit will be
given. You must show your work to get credit. Make sure to include proper units on your
answer.
1) 18 pts A mixture of NaCl and sucrose (C12H22O11) of combined mass 10.2 g is
dissolved in enough water to make up a 250.0 ml solution. The osmotic
pressure of the solution is 7.32 atm at 23ΛC. Calculate the mass present of
NaCl in the mixture.
ππππΆπ + ππΆ12π»22π11= 10.2 π
Looking for mass % NaCl
πππ π % πππΆπ =ππππΆπ
ππ‘ππ‘100% =
ππππΆπ
10.2 π100%
Use osmotic pressure to get another expression for mNaCl
Ξ = πππ π
7.32 ππ‘π = π(0.08206 πΏβππ‘π
πππβπΎ)(296.15πΎ)
π = 0.301 π =ππ πππ’π‘π
ππ πππ’π‘πππ=
πππ+ + ππΆπβ + ππΆ12π»22π11
0.25 πΏ
When the NaCl dissolves the ππππΆπ = πππ+ = ππΆπβ therefore our expression can
simplify to
0.301 π =2ππππΆπ+ππΆ12π»22π11
0.25 πΏ
0.075 πππ = 2ππππΆπ + ππΆ12π»22π11
Modify this expression to have mNaCl
0.075 πππ = 2ππππΆπ
ππππΆπ+
ππΆ12π»22π11
ππΆ12π»22π11
= 2ππππΆπ
58.443 π
πππ
+ππΆ12π»22π11
342.34 π
πππ
0.075 πππ = 2ππππΆπ
58.443 ππππ
+10.2 π β ππππΆπ
342.34 ππππ
1,500 π2
πππ= (684.68
π
πππ) ππππΆπ + 696.11
π2
πππβ (58.443
π
πππ) ππππΆπ
ππππΆπ = 1.45 π
Calculate mass %
πππ π % πππΆπ =1.45 π
10.2 π100% = 14.2%
7
2a) 8 pts Arsine, AsH3, is a highly toxic compound used in electronic industry for
the production of semiconductors. Its vapor pressure is 35 torr at
-111.95ΛC and 253 torr at -83.6ΛC. Using this date calculate the standard
enthalpy of vaporization.
ππ (ππ£ππ1
ππ£ππ2
) =βπ»π£ππ
π (
1
π2β
1
π1)
ππ (35 π‘πππ
253 π‘πππ) =
βπ»π£ππ
8.3145 π½πππβπΎ
(1
189.55πΎβ
1
161.2πΎ)
βπ»π£ππ = 17,700π½
πππ= 17.7
ππ½
πππ
2b) 8 pts What is the normal boiling point of arsine?
At the boiling point Pvap = atmospheric pressure = 1 atm=760 torr
ππ (760 π‘πππ
253 π‘πππ) =
17,700 π½πππ
8.3145 π½πππβπΎ
(1
189.55πΎβ
1
π)
π = 210. πΎ
8
3) 10 pts A positron and an electron annihilate each other upon colliding, thereby
producing energy:
πβ10 + π1
0 β 2 πΎ00
Assuming that both Ξ³ rays have the same energy, calculate the wavelength
of the electromagnetic radiation produced.
Calculate the Ξm (electron and positron weights are the same)
βπ = 0 β 2(9.10939 Γ 10β31 ππ) = β1.82188 Γ 10β30 ππ
Calculate the energy
βπΈ = βππ2 = (β1.82188 Γ 10β30 ππ)(2.99792 Γ 108 π
π )
2
βπΈ = β1.63742 Γ 10β13 π½ Therefore the energy released per photon is
1.63742Γ10β13 π½
2= 8.18710 Γ 10β14 π½
Calculate the wavelength of the photons
πΈ = βπ
π = ππ
πΈ =βπ
π
π =βπ
πΈ=
(6.62608 Γ 10β34 π½)(2.99792 Γ 108 ππ
)
8.18710 Γ 10β14 π½= 2.42631 Γ 10β12 π
π = 2.42631 Γ 10β3 ππ
9
4a) 8 pts Teflon is made from the monomer tetrafluoroethene. Draw the structure for
tetrafluoroethene and the repeating unit for Teflon.
F F
FF
Tetrafluoroethylene Teflon (repeating unit)
4b) 4 pts Is the synthesis of Teflon an example of addition polymerization or
condensation polymerization?
Addition
4c) 8 pts Draw the structure for the tripeptide, Val-Ala-Cys, in that order.
4d) 4 pts The analysis of a protein for its amino acid content is valuable in
determining the protein's⦠(circle one)
Primary Structure Secondary Structure Tertiary Structure
10
Multiple Choice Questions Each of the following multiple choice questions are worth 5 points. Your
answers need to be filled in on your ParSCORE form. Note: Your
ParSCORE will not be returned to you, therefore, for your records, you
may want to mark your answers on this sheet. On the ParSCORE you
need to fill in your perm number, test version, and name. Failure to do
any of these things will result in the loss of 1 point. Your perm number
is placed and bubbled in under the βID number.β Do not skip boxes or put
in a hyphen. In addition, leave bubbles blank under any unused boxes.
The version number (A) is bubbled in under the βtest form.β
1. Which of the following is paramagnetic?
A) [Co(NH3)6]3+ (strong field)
B) [Fe(CN)6]4- (strong field)
C) [Mn(en)3]2+ (strong field)
D) [Zn(H2O)6]2+
E) [Cu(en)3]+
Use the following to answer question 2:
The U-238 nucleus decays to form Pb-206 by and decays.
2. Calculate the number of decays.
A) 4
B) 8
C) 2
D) 6
E) none of these
3. The oxidation of secondary alcohols results in
A) aldehydes.
B) ketones.
C) ethers.
D) secondary alcohols.
E) esters.
4. The rate constant k is dependent on
A) the temperature.
B) the concentration of the reactant.
C) the order of the reaction.
D) the concentration of the product.
E) none of these
11
5. One of the hopes for solving the world's energy problem is to make use of the fusion
reaction
2
1 H +3
1 H 4
2 He + 1
0 n + energy
How much energy is released when 1 mol of deuterium is fused with 1 mol of tritium
according to the above reaction? The masses of the atoms and the neutrons are as
follows: 2
1 H = 2.0140 amu 3
1 H = 3.01605 amu
4
2 He = 4.002603 amu 1
0 n = 1.008665 amu
The speed of light is 2.9979 108 m/s.
A) 7.84 1044 J
B) 5.63 108 J
C) 56.3 J
D) 1.69 1012 J
E) none of these
6. Using the data below, calculate the vapor pressure of chloroform over a chloroform-
benzene solution at 25Β°C, which contains 50.0 g of CHCl3 and 50.0 g of C6H6. Assume
that the solution behaves ideally.
Vapor pressure at 25Β°C
benzene (C6H6) 94.4 torr
chloroform (CHCl3) 172.0 torr
A) 148 torr
B) 68.0 torr
C) 172 torr
D) 125 torr
E) none of these
7. The unit cell in a certain lattice consists of a cube formed by an anion at each corner, an
anion in the center, and a cation at the center of each face. The unit cell contains a net
A) 2 anions and 3 cations.
B) 5 anions and 6 cations.
C) 3 anions and 4 cations.
D) 5 anions and 3 cations.
E) none of these
12
8. If a tree dies and the trunk remains undisturbed for 13,750 years, what percentage of the
original 14C is still present? (The half-life of 14C is 5730 years.)
A) 45.0%
B) 5.20%
C) 19.0%
D) 2.20%
E) none of these
9. Pick the optically active molecule among the following:
A)
B)
C)
D)
E) none of these
10. The most likely decay mode (or modes) of the unstable nuclide 11
6 C would be
A) -particle production.
B) emission
C) positron production.
D) either positron production or electron capture or both.
E) electron capture.
11. For the reaction 2A+B products determine the value of K given the following data:
Exp [A]o (M) [B]o (M) Initial Rate (πππ
πΏβπ )
1 0.1 0.1 6.3Γ10-4
2 0.2 0.1 1.8Γ10-3
3 0.3 0.1 3.3Γ10-3
4 0.2 0.2 7.2Γ10-3
A) 0.29
B) 0.63
C) 1.3
D) 2.0
E) None of the above
13
12. A solution of two liquids, A and B, shows negative deviation from Raoult's law. This
means that
A) molecules of A interact weakly, if at all, with B molecules.
B) molecules of A interact more strongly with B than with A or and more strongly than
B with B.
C) the two liquids have a positive heat of solution.
D) molecules of A interact strongly with other A-type molecules.
E) the molecules of A hinder the strong interaction between B molecules.
C, B, B, A, D, B, A, C, B, D, D, B
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