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Chem 2
Practice Test
Practice Test 1: Ch 15,17
1. The following questions refer to the equilibrium shown here:
4NH3(g) + 502(g)
4NO(g) + 6H2O(g)
What would happen to the system if the pressure were decreased?
[A] The water vapor would become liquid water.
[B] The NO concentration would increase.
[C] Nothing would happen. [D] More oxygen would be produced.
[E] The ammonia concentration would increase.
2. The following questions refer to the equilibrium shown here:
4NH3(g) + 502(g)
4NO(g) + 6H2O(g)
What would happen to the system if oxygen were added?
[A] Nothing would happen.[B] More oxygen would be produced.
[C] The equilibrium would shift to the right.[D] More ammonia would be produced.
[E] The equilibrium would shift to the left.
3. The following questions refer to the equilibrium shown here:
4NH3(g) + 502(g)
4NO(g) + 6H2O(g)
For a certain reaction at 25.0
K
K
10 . This means that the reaction is
[A] endothermic. [B] never favorable.[C] exothermic.
[D] More information is needed.[E] None of these (a-d)
4. Name the following and identify the type of organic compounds as:
ALDEHYDE, ESTER, ETHER, AMINE, KETONE, PRIMARY ALCOHOL, SECONDARY
ALCOHOL, TERTIARY ALCOHOL, ACID, ALKANE, ALKENE, ALKYNE, AROMATIC
HYDROCARBON.
1.
2.
3.
4.
5.
B
r
B
r
6.
7.
1
Practice test 2 (Ch 16,18)
1. Consider the following rate law: Rate = k[A]n[B]m
How are the exponents n and m determined?
[A] By using the coefficients of the chemical formulas [B] By educated guess
[C] By experiment [D] By using the subscripts for the chemical formulas
[E] By using the balanced chemical equation
2. The following data were obtained for the reaction of NO with O2. Concentrations are in molecules/cm3
and rates are in molecules/cm3
[NO]0
[O 2 ]0
Initial Rate
1 10
18
1 10
2.0  1016
2 1018 1 1018
8.0  1016
18
3 1018 1 1018 18.0  1016
1 1018
2 1018
4.0  1016
1 1018
3 1018
6.0  1016
Which of the following is the correct rate law?
[A] Rate = k[NO][O2] [B] Rate = k[NO][O2]2 [C] Rate = k[NO]2 [D] Rate = k[NO]2[O2]2
[E] Rate = k[NO]2[O2]
For questions 3,4,5,6 refer the equation and data given below.
The following questions refer to the reaction shown below:
A + 2B → 2AB
Initial Rate of
Initial [A] Initial [B] Disappearance of A
Experiment
(mol / L)
(mol / L)
(mol / L  s)
1
0.16
0.15
0.08
2
0.16
0.30
0.30
3
0.08
0.30
0.08
3. What is the rate law for this reaction?
[A] Rate = k[A]2[B]
[B] Rate = k[A][B]2
[C] Rate = k[A]2[B]2
[D] Rate = k[A][B]
[E] Rate = k[B]
4. What is the magnitude of the rate constant for the reaction?
[A] 140 [B] 21 [C] 119 [D] 164 [E] 79
5. What are the units for the rate constant for this reaction?
3/L [E] L2/mol2
[A] L3/mol3
6. What is the overall order of this reaction?
[A] 2 [B] 4 [C] 3 [D] 1 [E] 0
7. The catalyzed pathway in a reaction mechanism has__________ activation energy and thus causes a
__________ reaction rate.
[A] lower, steady [B] lower, higher [C] higher, higher [D] higher, steady [E] higher, lower
8. The rate constant k is dependent on
I. the concentration of the reactant.
II. the nature of the reactants.
III. the temperature.
IV. the order of the reaction.
[A] none of these [B] one of these [C] two of these [D] three of these [E] all of these
2
9. The questions 9,10,11 below refer to the following diagram:
At what point on the graph is the activated complex present (transition state)?
[A] point X [B] point W [C] point Y [D] point Z [E] none of these
10. Why is this reaction considered to be exothermic?
[A] Because energy difference B is greater than energy difference C plus energy difference A
[B] Because energy difference A is greater than energy difference C
[C] Because energy difference B is greater than energy difference A
[D] Because energy difference B is greater than energy difference C
[E] Because energy difference A and energy difference C are about equal
11. If the reaction were reversible, would the forward or the reverse reaction have a higher activation
energy?
[A] The diagram shows no indication of any activation energy.
[B] The reverse activation energy
[C] The forward and reverse activation energies are equal.
[D] The forward activation energy
[E] none of these
Questions 12 and 13 refer to the equation given below.
The following questions refer to the reaction 2A2 + B2
proposed:
step 1 (very slow) A 2 + B2  R + C
step 2 (slow)
A2 + R  C
12. What is the molecularity of step 2?
[A] termolecular [B] the molecularity cannot be determined [C] unimolecular
[D] quadmolecular [E] bimolecular
13. Which step is “rate determining”?
[A] both steps [B] step 2 [C] step 1 [D] a step that is intermediate to step 1 and step 2
[E] none of these
14. The reaction
3NO → N2O + NO2
is found to obey the rate law Rate = k[NO]2. If the first half-life of the reaction is found to be 2.0 s, what
is the length of the fourth half-life?
[A] 2.0 s [B] 4.0 s [C] 12.0 s [D] 16.0 s [E] 8.0 s
15. The decomposition of ozone may occur through the two-step mechanism shown:
step 1 O3  O2 + O
step 2 O3 + O  2O2
The oxygen atom is considered to be a(n)
[A] catalyst [B] product [C] activated complex [D] reactant [E] reaction intermediate
3
Questions 16 and 17 refer to the graph given below:
16. Use the potential energy diagram shown to answer the following:
Which letter shows the change in energy for the overall reaction?
17. Use the potential energy diagram shown to answer the following:
Which letter shows the activation energy using a catalyst?
2 + I2 is second order, which of the following will yield a linear plot?
[A] [HI] vs time [B] ln [HI] vs time [C] 1/[HI] vs time [D] log [HI] vs time
For questions 19,20,21 refer the equation given below.
The reaction
A→B+C
is second order in A. When [A]0 = 0.100 M, the reaction is 20.0% complete in 40.0 minutes.
mol).
1
[A] 5.58 x
[B] 1.00 [C] 1.60 x
[D] 6.25 x
[E] none of these
20. Calculate the half-life for the reaction.
2 min [B] 1.00 x
1 min [C] 1.11 x101 min [D] 1.00 x102 min[E] none of these
[A] 1.60 x
21. A first-order reaction is 40.% complete at the end of 50. minutes. What is the value of the rate
constant (in min )?
[A] 8.0 x 10
[B] 1.8 x 10
[C] 1.0 x 10
[D] 1.2 x 10
[E] none of these
+
22. Calculate the [H ] in a solution that has a pH of 11.70.
[A] 11.7 M[B] 2.0 x10 2 M[C] 5.0 x10
M[D] 2.3 M [E] none of these
10
M?
[A] The [H] is 4 x 10
M.[B] The Kw is independent of what the solution contains.
[C] The solution is acidic.[D] Kw = 1 x 10
[E] The solution is basic.
24. For weak acid, HX, Ka = 1.0 x 10 . Calculate the pH of a 0.10 M solution of HX.
[A] 3.50[B] 3.00[C] 6.00[D] 2.50[E] none of these
24. The following questions refer to a solution that contains 1.00 M hydrofluoric acid, HF
(Ka = 7.2x10 ), and 3.00 M hydrocyanic acid, HCN (Ka = 6.2 x 10
).
What is the pH of this mixture of weak acids?
[A] 3.14[B] 1.57[C] 9.21[D] 4.37[E] 0.00
25. Calculate the [H+] in a 0.010 M solution of HCN, Ka = 6.2 x 10 0.
[A] 3.6 x
M[B] 2.5 x10
M[C] 1.0x
M[D] 6.2x
M[E] none of these
26. A solution of 2.5 M weak acid is 0.52% ionized. What is the Ka value of this acid?
[D] 0.11[E] none of these
27. What is the pH of a 0.45 M KCl solution?
[A] 9.2[B] 7.0[C] 1.4[D] 10.5[E] 4.5
28. The conjugate acid and conjugate base of bicarbonate ion, HCO3 , are, respectively:
[A] H3O+ and CO3
[B] H3O+ and OH
[C] H2CO3 and OH
[D] CO3
and OH
[E] H2CO3 and CO3
29. Which factor listed below is most important in determining the strength of an oxyacid?
[A] the size of the molecule[B] the number of oxygen atoms present in the molecule
4
[C] the identity of the central atom in the molecule
[D] the ability of the molecule to change atomic orientation
[E] none of these
30. The pH of a 1.0 M sodium acetate solution is:
[A] 7.0 [B] less than 7.0 [C] not enough information is given [D] greater than 7.0
[E] none of these (a-d)
31. A weak acid, HF, is in solution with dissolved sodium fluoride, NaF. If HCl is added, which ion will
react with the extra hydrogen ions from the HCl to keep the pH from changing?
[A] F [B] Na+[C] Na [D] OH [E] none of these
32. Which of the following would produce the most acidic solution?
[A] HOCl[B] HOI[C] HOCl2[D] HOBr[E] HOAt
33. Which of the following is true for a buffered solution?
[A] The solution resists change in its [H+].
[B] The solution will not change its pH very much even if a concentrated acid is added.
[C] Any H+ ions will react with a conjugate base of a weak acid already in solution.
[D] The solution will not change its pH very much even if a strong base is added.
[E] all of these
34. The following data were obtained for the reaction:
2ClO2 (aq) + 2OH- (aq) → ClO3- (aq) + ClO2- (aq) + H2O (l)
Rate= -∆[ClO2] / ∆t (Find the m and n for both the reactants and then determine the rate law)
[ClO2] 0
[OH-]0
Initial Rate
Mol/L
mol/L
(mol/L.s)
0.0500
0.100
5.75 x10-2
0.100
0.100
2.30 x10-1
0.100
0.0500
1.15 x10-1
1. Determine the rate law and value of the rate constant.
2. What would be the initial rate for an experiment with [ClO2] 0 = 0.175 mol/L
[OH-]0 = 0.0844 mol/L.
35. A certain reaction has the general formula:
aA →bB
At a particular temperature [A]0 =2.00 x 10-2 M.A plot of ln [A] v/s time resulted in a straight line
with a slope of -2.97 x 10-2 min-1
a) Determine the rate law, the Integrated rate law, and the value of the rate contstant.
b) Calculate the half life of the reaction.
c) How much time is required for the concentration of A to decrease to 2.50 x 10-3 M ?
36. With an increase in temperature for 10 K, the rate of the reaction doubles. Calculate the activation
Energy for a temperature increase from 25 C to 35 C
37. The reaction: (CH3)3CBr + OH-→(CH3)3COH + Br- is first order with respect to OHA plot of k v/s 1/T gave a straight line with a slope of -1.10 x 104K and Y intercept of 33.5. Assume k has
units of s-1.
a) Determine the activation energy.
b) Determine the value of frequency factor A.
38. If 100.0 mL of 0.100 M H2NNH2 ( Kb= 3.0 x 10-6) is titrated with 0.200 M HNO3. Calculate the pH in
the following cases:
1) after a total of 25.0 mL HNO3 is added.
2) at equvivalence point.
3) after 100.0 mL of HNO3 is added.
39. Calculate the equilibrium concentration of AsO43- in a 0.20M H3AsO4 solution. Show your work for
full credit. Ka1 = 5 x 10-3 Ka2 = 8 x 10-8 Ka3 = 6 x 10-10
5
Practice Test 3 (Ch 19,23)
1. Which of the following statements concerning the complex ion Co(en)2Cl2+ is true?
(en = ethylenediamine, NH2CH2CH2NH2)?
[A] The complex ion contains Co(I).
[B] The complex ion exhibits cis and trans geometric isomers, but no optical isomers.
[C] The geometric isomers of the complex ion have identical chemical properties.
[D] Since en is a strong field ligand (large ∆), the complex ion is paramagnetic.
[E] The complex ion exhibits two geometric isomers (cis and trans) and two optical isomers.
2. The complexes of Zn2+ are all diamagnetic.
[A] True [B] False
3. Which model(s) accounts for the magnetism and color of coordination compounds?
I. the localized electron model
II. the crystal field model
[A] I [B] both I and II [C] neither I nor II [D] II
4. The complex ions containing Zn2+ are intensely colored.
[A] True [B] False
5. The spectrochemical series is
I < Br < Cl < F < OH < H2O < NH3 < en < NO2 < CN
Which of the following complexes will absorb visible radiation of the highest energy (shortest
wavelength)?
[A] [Co(I)6]
[B] [Co(en)3]3+ [C] [Co(H2O)6]3+ [D] [Co(NH3)6]3+[E] [Co(OH)6]
6. The phenomenon called the __________ contradiction is responsible for the great similarity in
atomic size and chemistry of 4d and 5d elements.
[A] coordination [B] isomeric [C] none of these [D] lanthanide [E] transition
7. Which of the metal ions in the following complex ions has a d5 electron configuration?
[A] Co(CN)4 [B] Mo(NH3)63+ [C] RhCl6
[D] V(H2O)62+ [E] Fe(CN)6
8. Which metal ion has a d5 electron configuration?
[A] Os2+[B] Co2+[C] Pd2+[D] Fe3+[E] Ag+
9. Which of the following ligands might give linkage isomers?
[A] NO2 [B] SCN [C] H2NHC2CH2NH2[D] a, b, and c[E] a and b
10. How many of the following compounds exhibit geometric isomers?
I. Pt(NH 3 )2 Cl 2 (square planar)
II. [Co(H 2O)2 ]Cl3
III.
Ni(NH 3 )4 ( NO 2 )2
IV. K 2 [CoCl 4 ]
[A] 2[B] 1[C] 4[D] 3[E] 0
11. All tetrahedral complex ions are high spin.
[A] True[B] False
12. The election configuration of Mn2+ is [Ar] 4s23d3.
[A] True[B] False
13. Specify the number of unpaired electrons in CoF63 (weak field).
a) 0 b) 1 c) 2 d) 4 e) 5
14. Which of the following compounds has the lowest solubility in mol/L in water?
[A] Al(OH)3
Ksp  2  1023 [B] PbSO4
Ksp  13
.  108
[C] Sn(OH)2
Ksp  3  1027 [D] MgC2O4
Ksp  8.6  105
6
Ksp  10
.  1028
[E] CdS
15. The molar solubility of PbI2
M. Calculate the value of Ksp for PbI2.
[A] 1.5
16. Calculate the concentration of chromate ion, CrO4
(Ksp
[E] none of these
, in a saturated solution of CaCrO4.
)
17. The molar solubility of BaCO3 (Ksp
M [E] 0.027 M
) in 0.10 M BaCl2 solution is:
[D] 0.10 [E] none of these
18. The correct mathematical expression for finding the molar solubility (S) of Sn(OH) 2 is:
[A] 2S3 = Ksp [B] 108S5 = Ksp [C] 2S2 = Ksp [D] 4S3 = Ksp [E] 8S3 = Ksp
19. A weak acid, HF, is in solution with dissolved sodium fluoride, NaF. If HCl is added, which
ion will react with the extra hydrogen ions from the HCl to keep the pH from changing?
[A] F [B] Na+[C] Na [D] OH
20. Which of the following is true for a buffered solution?
[A] The solution resists change in its [H+].
[B] The solution will not change its pH very much even if a concentrated acid is added.
[C] Any H+ ions will react with a conjugate base of a weak acid already in solution.
[D] The solution will not change its pH very much even if a strong base is added.
[E] all of these
21. A solution is prepare by mixing 50.0mL of 0.10 M Pb(NO3)2 with 50.0 mL of 1.0 M KCl.
Calculate the concentrations of Pb2+ and Cl- at equilibrium.
Ksp for PbCl2 (s) is 1.6 x 10-5
22. If 100.0 mL of 0.100 M H2NNH2 ( Kb= 3.0 x 10-6) is titrated with 0.200 M HNO3. Calculate
the pH in the following cases:
1) after a total of 25.0 mL HNO3 is added. 2) at equvivalence point.
3) after 100.0 mL of HNO3 is added.
23. Consider the titration of a weak base with a strong acid.
B + H+ ↔ BH+
On the curve given below indicate the points that correspond to the following:
Label the points on the graph and even fill in the blanks with the correct points.
1. pH depends only on [HA] ______________________
2. pH depends only on [A-] _______________________
3. equvivalence point __________________________
4. pH=pKa _________________________________
5. pH depends only on excess of strong acid added. _____________________
Analysis of Acids
NaOH added vs pH
14
12
10
pH
8
6
4
2
0
0
2
4
6
8
10
NaOH added (mL)
12
14
16
18
acetic acid
24. Calculate the mass of sodium acetate that must be added to 500.0 mL of 0.200 M acetic acid
to form a pH=5.00 buffer. Ka for acetic acid = 1.8 x 10-5
25. Name the following:
1) [Cr(en)3](ClO4 ) 3 _____________________________________________________
7
2) [Co(NH3)4(H2O)Br]Br2 ______________________________________________
26. Write formulas for the following:
1) Pentaamminechlorochromium(III)chloride ________________________
2) Bariumtetrabromoferrate(III) __________________________
3) Hexaaquachromium(III) sulfate ________________________
27. How many unpaired electrons are present in the tetrahedral ion FeCl4-? Draw the crystal field
diagram.
28. Draw any five isomers for:
[Cr(NH3)2(H2O)2Br2]+
***********************************************************************
Practice test 4(Ch 20,21,24)
Multiple choice:
1. In which reaction is S expected to be positive?
[A] 2O2(g) + 2SO(g)  2SO3(g) [B] H2O(1)  H2O(s)
[C] I2(g)  I2(s) [D] CH3OH(g) + (3/2)O2(g)  CO2(g) + 2H2O(l) [E] none of these
2. A chemical reaction is most likely to be spontaneous if it is accompanied by
[A] increasing energy and increasing entropy.
[B] lowering energy and increasing entropy.
[C] increasing energy and decreasing entropy.
[D] lowering energy and decreasing entropy.
[E] none of these (a-d)
Questions3-5are based on the diagram and equations given below.
3.Consider the galvanic cell shown below (the contents of each half-cell are written beneath each
compartment):
The standard reduction potentials are as follows:
Cr 3+ + 3e  Cr(s)

Br2 (aq) + 2e  2Br
E = 0.73 V

E = +1.09 V
What is E for this cell?
[A] 1.82 V [B] 4.75 V [C] 1.79V [D] 0.36 V [E] 4.40 V
4.What is the value of E for this cell at 25C?
[A] 1.88 V [B] 0.59 V [C] 1.76 V [D] 2.21 V [E] 2.12 V
5. Which of the following statements about this cell is false?
[A] Reduction occurs at the Pt electrode.
[B] The cell is not at standard conditions.
[C] This is a galvanic cell.
[D] To complete the circuit, cations migrate into the left half-cell and anions migrate into the
right half-cell from the salt bridge.
[E] Electrons flow from the Pt electrode to the Cr electrode.
8
6. Which statement below is not upheld by the second law of thermodynamics?
[A] The entropy of a perfect crystal at 0 K is zero. [B] Machines always waste some energy.
[C] A machine is never 100% efficient.
[D] The change of entropy of the universe is always positive. [E] All of these
7. Which of the following is the strongest oxidizing agent?

MnO 4 + 4H + + 3e  MnO 2 + 2H 2O

I2 + 2e  2I

E  = 1.68 V
E  = 0.54 V
Zn 2+ + 2e  Zn
E  =  0.76 V
[A] Zn [B] I2 [C] Zn2+ [D] MnO4[E] MnO2
8. For a particular chemical reaction
H = 5.5 kJ and S = 25 J/K
Under what temperature condition is the reaction spontaneous?
[A] When T > 220 K. [B] The reaction is spontaneous at all temperatures.
[C] When T < 220 K. [D] When T < 220 K.
[E] The reaction is not spontaneous at any temperature.
9. For the process CHCl3(s)  CHCl3(l), H = 9.2 kJ/mol and S = 43.9 J/mol/K. What is the
melting point of chloroform?
[A] 63C [B] 5C [C] 210C [D] 5C [E] 63C
10. In which case must a reaction be spontaneous at all temperatures?
[A] H = 0, S is negative. [B] S = 0, H is positive. [C] H is negative, S is positive.
[D] H is positive, S is positive. [E] none of these
10. What is the oxidation state of Hg in Hg2Cl2?
[A] 2 [B] 0 [C] 1 [D] +2 [E] +1
11. Which of the following is true for the cell shown here?
Zn(s)  Zn2+(aq)  Cr3+(aq)  Cr(s)
[A] The electrons flow from the zinc to the chromium.
[B] The electrons flow from the cathode to the anode.
[C] The chromium is oxidized.
[D] The zinc is reduced.
[E] The electrons flow from the chromium to the zinc.
12. Which type of battery has been designed for use in space vehicles?
[A] mercury cells [B] fuel cells [C] silver cells [D] lead storage [E] alkaline dry cell
13. Electron capture transforms 40
19 K into what nuclide?
[A]
40
18
A [B]
40
20
Ca [C] 42 H [D]
40
19
K [E]
39
20
Ca
14. An unstable isotope of rhenium, 191 Re, has a half-life of 9.8 minutes and is a beta producer.
What is the other product of the reaction?
[A] 191 Os [B] 192 Pt [C] 190 W [D] 190 Os [E] 191 W
15. Which of the following processes decreases the atomic number by 1?
[A] electron capture [B] positron production [C] gamma-ray production
[D] beta-particle production
[E] At least two of these processes decrease the atomic number by 1.
16. Which types of processes are likely when the neutron-to-proton ratio in a nucleus is too low?
I.  decay
II.  decay
III.
positron production
IV.
electron capture
[A] II, III [B] II, IV [C] I, II [D] III, IV [E] II, III, IV
9
17. The rate constant for the beta decay of thorium-234 is 2.88 x10 /day. What is the half-life
of this nuclide?
[A] 24.1 days [B] 101 days [C] 0.693 days [D] 53.1 days [E] 1.22 days
18. Identify the missing particle in the following nuclear equation:
241
95
Am  42 He 
 201 n
246
247
245
244
[A] 243
97 Bk [B] 97 Bk [C] 97 Bk [D] 99 Bk [E] 97 Bk
19. In the following nuclear equation, identify the missing product:
43
20
Ca   
11H
46
46
44
[A] 42
18 Ar [B] 21Sc [C] 22Ti [D] 22Ti
20. A radioactive element has a half-life of 1.0 hour. How many hours will it take for the number
of atoms present to decay to 1/16th of the initial value?
[A] 2.77[B] 16[C] 4[D] 8[E] 15
21. The I-131 nuclide has a half-life of 8 days. If you originally have a 1.8-kg sample, after 2
months you will have approximately
[A] 40 g [B] 20 g [C] 10 g [D] 30 g
[E] less than 1 g
22. If 214
82 Pb undergoes a beta decay and the product of this decay undergoes another beta decay,
which nuclide is produced?
214
214
212
206
[A] 214
82 Bi [B] 82 Po [C] 82 Pb [D] 83 Bi [E] 82 Pb
23. As atomic mass increases, the proton/neutron ratio of stable nuclides decreases.
[A] True [B] False
24. A common car battery consists of six identical cells each of which carries out the reaction
Pb(s) + PbO2 (s)+ 2HSO4- (aq)+ 2H+ (aq)→ 2PbSO4 (aq)+ 2H 2O(l)
Plug in the oxidation numbers for each element to find the number of electrons involved.
a) The value of E° for such a cell is 2.04 V. Calculate ∆G° at 25°C for the reaction.
b) Suppose that in starting a car on a cold morning a current of 125 amperes is drawn for 15.0
seconds from a cell of the type described above. How many grams of Pb would be consumed?
(The atomic weight of Pb is 207.19.)
c) Calculate E at 25 C for this battery when [HSO4- ]=[H+ ]=4.5 M.
25. Consider the following reaction at 298 K.
2SO2 (g) + O2(g) →2SO3(g)
-300
0
-371 ∆Gf in kJ
An equilibrium mixture contains O2(g) and SO3(g) at partial pressures of 0.50 atm and 2.0 atm
respectively. Determine the equilibrium partial pressure of SO2 in the mixture. Will the reaction
be most favored at low or high temperatures, assuming standard conditions?
26. Am-241 undergoes undergoes an α,α,β,α,α,βα,α,α,β,α,β sequence of radioactive decay.
Identify all of the radioisotopes and the final stable isotope formed.
27. The half-life of phosphorus-32 is 14.3 days. What mass of phosphorus-32 is left from an
original sample of 175 mg of Na3 32PO4 after 35.0 days? Assume the atomic mass of 32 P is
32.0.Hint: Calculate the molar mass of Na3 32PO4 first.
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