1082-3rd Chem Exam(C)-1090617
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Carbon-11 decays by ________.
A) alpha emission B) positron emission C) beta emission D) neutron capture
E) photon emission Answer: B
2) What happens to the mass number and the atomic number of an element when it emits gamma radiation?
A) The mass number decreases by four and the atomic number decreases by two.
B) The mass number increases by four and the atomic number increases by two.
C) The mass number remains unchanged while the atomic number increases by one.
D) The mass number remains unchanged while the atomic number decreases by one.
E) The mass number and atomic numbers remain unchanged.
Answer: E
3) What happens to the mass number and the atomic number of an element when it undergoes alpha decay?
A) The mass number does not change and the atomic number increases by 2.
B) The mass number decreases by 4 and the atomic number decreases by 2.
C) The mass number increases by 4 and the atomic number does not change.
D) The mass number increases by 2 and the atomic number decreases by 1.
E) The mass number does not change and the atomic number increases by 1.
Answer: B
4) The mass of a proton is 1.00728 amu and that of a neutron is 1.00867 amu. What is the binding energy for per mole of Co-59 ? (The mass of a cobalt-59 nucleus is 58.9332 amu.)
A) 1.34 × 10-34 J B) 4.87 × 1013 J C) 4.80 × 1010 J D) 2.50 × 1012 J E) 4.87 × 1010 J Answer: B
5) The half-life of cobalt-60 is 5.20 yr. How many milligrams of a 2.000-mg sample remain after 9.50 years?
A) 0.565 B) 1.095 C) 7.03 × 10-22 D) 1.435
E) 7.076 Answer: A
6) In the nuclear transmutation represented by 168O(p, α) 137N, the emitted particle is ________.
A) a neutron.
B) an alpha particle.
C) a positron.
D) a beta particle.
7) The product of the nuclear reaction in which 40Ar is subjected to neutron capture followed by alpha emission is ________.
A) 35Ar B) 36S C) 45Ca D) 41Ar E) 37S
Answer: E
8) Cobalt-60 is produced by a three reaction process involving neutron capture, beta-emission, and neutron capture. The initial reactant in the production of cobalt-60 is ________.
A) 60Fe B) 59Co C) 58Fe D) 61Co E) 56Fe
Answer: C
9) Strontium-90 is a byproduct in nuclear reactors fueled by the radioisotope uranium-235. The half-life of strontium-90 is 28.8 yr. What percentage of a strontium-90 sample remains after 175.0 yr?
A) 6.08 B) 84.8 C) 1.48 D) 0.230 E) 16.5
Answer: C
10) A rock contains 0.153 mg of lead-206 for each milligram of uranium-238. The half-life for the decay of uranium-238 to lead-206 is 4.5 × 109 yr. The rock was formed ________ years ago.
A) 1.06 × 109 B) 7.33 × 108 C) 5.60 × 108 D) 8.08 × 108 E) 6.89 × 108 Answer: A
11) Which one of the following is the correct formula for pentaamminechlorocobalt (III) chloride?
A) [Co(NH3)5Cl]Cl2 B) [Cl(NH3)5Co]Co2 C) [Co(NH3)5]Cl4 D) [Co(NH3)4Cl]Cl2
E) [Co(NH3)6Cl]Cl2 Answer: A
12) Based on electron configuration, which is most likely colorless?
A) [Cr(NH3)5Cl]2+
B) [Cd(NH3)4]2+
C) [Co(NH3)6]2+
D) [Cu(NH3)4]2+
E) [Ni(NH3)6]2+
Answer: B
13) Which element has the largest bonding atomic radius?
A) scandium B) manganese C) chromium D) titanium E) vanadium
Answer: A
14) Which ion shown has empty 5s orbitals?
A) Mo2+
B) Y3+
C) Nb2+
D) Zr4+
E) All choices have empty 5s orbitals.
Answer: E
15) Which of the following is not a chelating agent?
A) ethylenediamine B) ortho-phenanthroline C) carbonate ion
D) triphosphate ion E) water
Answer: E
16) A substance with unpaired electrons will be ________.
A) permanently magnetic B) slightly attracted to a magnet C) nonmetallic
D) slightly repelled by a magnet E) brightly colored
Answer: B
17) How many d electrons are associated with the metal ion in [Cr(NH3)6]3+?
A) 0 B) 4 C) 1 D) 3 E) 2
Answer: D
18) What two oxidation states are more frequently observed in the first transition series than in the third?
A) +5 and +6 B) +3 and +7 C) +3 and +5 D) +2 and +3 E) +2 and +7
Answer: D
19) A complex that absorbs light at 700 nm will appear ________.
A) yellow B) violet C) green D) red E) orange
Answer: C
20) Which of the following will display optical isomerism?
A) octahedral [Co(NH3)5Cl]2+
B) square-planar [Rh(CO)2Cl2]- C) octahedral [Co(H2NC2H4NH2)3]3+
D) square-planar [Pt(H2NC2H4NH2)2]2+
E) octahedral [Co(NH3)6]3+
Answer: C
21) Which of the following compounds does not contain a CO bond?
A) aldahydes B) carboxylic acids C) esters
D) alcohols
E) none of the above Answer: D
22) How many chiral centers are there in CH3CHCHCH2CHBr2?
A) 3 B) 4 C) 1 D) 2 E) 0
Answer: E
23) Hybridization of the carbon atom indicated by (*) in CH3-*CH2-CH3, *CH2CH2, and CH3-*C≡CH is ________, ________, and ________, respectively.
A) sp2, sp3, sp B) sp3, sp, sp2 C) sp, sp3, sp2 D) sp, sp2, sp3 E) sp3, sp2, sp Answer: E 24)
is called a(n) ________.
A) amide B) ketone C) amine D) aldehyde E) ester
Answer: A
25) Which one of the following could be a straight-chain alkane?
A) C9H20 B) C3H3 C) C4H6 D) C3H6 E) C5H4
Answer: A
26) In general, ________ are the most reactive hydrocarbons.
A) olefins B) alkenes C) alkynes D) alkanes
E) cycloalkanes Answer: C
27) The melting and boiling points of hydrocarbons are determined by ________.
A) ionic bonding
B) dipole-dipole attraction C) ion-dipole attraction D) hydrogen bonding
E) London forces Answer: E
28) How many structural isomers of heptane exist?
A) 4 B) 9 C) 2 D) 8 E) 6
Answer: B
29) Ethers can be made by condensation of two ________ molecules by splitting out a molecule of water.
A) alcohol B) ketone C) alkyne D) olefin E) aldehyde
Answer: A
30) The compound below is a(n) ________.
A) ester
B) carboxylic acid C) amine
D) ketone E) aldehyde Answer: A
31) The standard cell potential (E°) of a voltaic cell constructed using the cell reaction below is 0.76 V:
Zn (s) + 2H+ (aq) → Zn2+ (aq) + H2 (g)
With PH2 = 1.0 atm and [Zn2+] = 1.0 M, the cell potential is 0.53 V. The concentration of H+ in the cathode compartment is ________ M.
A) 1.7 × 10-8 B) 1.3 × 10-4 C) 1.1 × 10-2 D) 1.3 × 10-11 E) 7.7 × 103 Answer: B
32) The standard cell potential (E°cell) for the reaction below is +1.10 V. The cell potential for this reaction is ________ V when the concentration of [Cu2+] = 1.0 × 10-5 M and [Zn2+] = 3.0 M.
Zn (s) + Cu2+ (aq) → Cu (s) + Zn2+ (aq)
A) 1.26 B) 1.42 C) 0.94 D) 1.10 E) 0.78
Answer: C
33) Which transformation could take place at the anode of an electrochemical cell?
A) HAsO2 to As B) O2 to H2O C) F2 toF-
D) Cr2O72- → Cr2+
E) None of the above could take place at the anode.
Answer: E
34) How many kilowatt-hours of electricity are used to produce 4.50 kg of magnesium in the electrolysis of molten MgCl2 with an applied emf of 5.00 V? 1V = 1 J/C; 1 kWh = 3.6 × 106 J
A) 12.4 B) 0.0201 C) 24.8 D) 0.0496 E) 49.6
Answer: E
35) How many minutes will it take to plate out 16.22 g of Al metal from a solution of Al3+ using a current of 14.6 amps in an electrolytic cell?
A) 66.2 B) 153 C) 11900 D) 53.0 E) 199
36) Which one of the following reactions is a redox reaction?
A) Pb2+ + 2Cl- → PbCl2 B) NaOH + HCl → NaCl + H2O C) AgNO3 + HCl → HNO3 + AgCl D) None of the above is a redox reaction.
Answer: D
37) Which element is reduced in the reaction below?
Fe2+ + H+ + Cr2O72- → Fe3+ + Cr3+ + H2O
A) Fe B) O C) H D) Cr
Answer: D Table 20.1
Half Reaction E°(V)
F2 (g) + 2e- → 2F- (aq) +2.87 Cl2 (g) + 2e- → 2Cl- (aq) +1.359 Br2 (l) + 2e- → 2Br- (aq) +1.065 O2 (g) + 4H+ (aq) + 4e- → 2H2O (l) +1.23 Ag+ + e- → Ag (s) +0.799 Fe3+ (aq) + e- → Fe2+ (aq) +0.771 I2 (s) + 2e- → 2I- (aq) +0.536 Cu2+ + 2e- → Cu (s) +0.34 2H+ + 2e- → H2 (g) 0 Pb2+ + 2e- → Pb (s) -0.126 Ni2+ + 2e- → Ni (s) -0.28
Li+ + e- → Li (s) -3.05
38) Which of the halogens in Table 20.1 is the strongest oxidizing agent?
A) Br2 B) F2 C) I2 D) Cl2
E) All of the halogens have equal strength as oxidizing agents.
Answer: B
39) What is the coefficient of the permanganate ion when the following equation is balanced?
MnO4- + Br- → Mn2+ + Br2 (acidic solution)
A) 1 B) 3 C) 2 D) 4 E) 5
Answer: C
40) What is the coefficient of Fe3+ when the following equation is balanced?
CN- + Fe3+ → CNO- + Fe2+ (basic solution)
A) 1 B) 2 C) 3 D) 4 E) 5
Answer: B
