Download Name: 1) What is the oxidation number of sulfur in H SO ? A)

7181 - 1 - Page 1
Name: ____________________________________________
1)
What is the oxidation number of sulfur in H2SO4?
A) -2
2)
B) -2
B) -2
D) -7
C) +6
D) -4
C) +1
B) +1 and +3
D) +2
C) +1 and +2
D) +2 and +3
In the reaction Cl 2 + H2O ‡‡ˆ HClO + HCl, the oxidation number of chlorine
A) neither decreases nor increases
B) decreases, only
7)
C) -1
If element X forms the oxides XO and X2O3, the oxidation numbers of element X are
A) +2 and +4
6)
B) +1
The oxidation number of hydrogen in sodium hydride (NaH) is
A) -1
5)
D) +6
What is the oxidation number of oxygen in HSO4-?
A) +1
4)
C) +4
What is the oxidation number of iodine in KIO4?
A) +7
3)
B) 0
C) both decreases and increases
D) increases, only
In the reaction
2CrO42-(aq) + 2H+(aq) ‡‡ˆ Cr2O72-(aq) + H2O(l),
the oxidation number of chromium
A) decreases
8)
B) NO2
C) a change in oxidation number
D) the formation of ions
B) protons
D) electrons
C) unrelated to the total number of electrons lost
D) less than the total number of electrons lost
For a redox to occur, there must be a transfer of
A) neutrons
13)
C) neutrons
In any oxidation-reduction reaction, the total number of electrons gained is
A) greater than the total number of electrons lost
B) equal to the total number of electrons lost
12)
D) N2
Oxidation-reduction reactions occur because of the competition between particles for
A) positrons
11)
C) N2O
A redox reaction always involves
A) a change of phase
B) the transfer of protons
10)
C) remains the same
The oxidation number of nitrogen is highest in
A) NH3
9)
B) increases
B) electrons
C) ions
D) protons
Given the reaction:
Zn(s) + Cu2+(aq) ‡‡ˆ Zn2+(aq) + Cu(s)
Which particles must be transferred from one reactant to the other reactant?
A) neutrons
B) protons
C) ions
D) electrons
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14)
Which statement correctly describes a redox reaction?
A)
B)
C)
D)
15)
16)
The
The
The
The
oxidation
oxidation
oxidation
oxidation
half-reaction
half-reaction
half-reaction
half-reaction
and the reduction half-reaction occur simultaneously.
occurs spontaneously but the reduction half-reaction does not.
occurs after the reduction half-reaction.
occurs before the reduction half-reaction.
Which equation represents a redox reaction?
A) SO32- + 2H+ ‡‡ˆ H2SO3
C) SO2 + H2O ‡‡ˆ H2SO3
B) O2 + 2H2 ‡‡ˆ 2H2O
D) OH- + H+ ‡‡ˆ H2O
Which is a redox reaction?
A) 2KBr + F2 ‡‡ˆ 2KF + Br2
B) 2HCl + Mg(OH)2 ‡‡ˆ 2HOH + MgCl2
C) Ca(OH) 2 + Pb(NO3)2 ‡‡ˆ Ca(NO3)2 + Pb(OH)2
D) 2NaCl + H2SO4 ‡‡ˆ Na2SO4 + 2HCl
17)
Which is a redox reaction?
A) NaOH + HCl ‡‡ˆ NaCl + H2O
B) CaCO3 ‡‡ˆ CaO + CO2
18)
Which is a redox reaction?
A) Mg + 2HCl ‡‡ˆ MgCl 2 + H2
B) MgCl 2 + 6H2O ‡‡ˆ MgCl 2d6H2O
19)
C) 2H2O ‡‡ˆ 2H2 + O2
D) 2NH4Cl + Ca(OH)2 ‡‡ˆ 2NH3 + 2H2O + CaCl 2
C) Mg2+(aq) + 2OH-(aq) ‡‡ˆ Mg(OH)2
D) Mg(OH)2 + 2HCl ‡‡ˆ MgCl 2 + 2H2O
Which equation represents a redox reaction?
A) H+ + C2H3O2- ‡‡ˆ HC2H3O2
C) 2Na+ + S2- ‡‡ˆ Na2S
B) NH3 + H+ + Cl - ‡‡ˆ NH4+ + Cl -
D) Cu + 2Ag+ + 2NO3- ‡‡ˆ 2Ag + Cu2+ + 2NO3-
20) Which is not an oxidation and reduction reaction?
21)
A) 2K + 2H2O ‡‡ˆ 2KOH + H2
C) 2KClO3 ‡‡ˆ 2KCl + 3O2
B) 2K + Cl 2 ‡‡ˆ 2KCl
D) KOH + HCl ‡‡ˆ KCl + H2O
Given the redox reaction:
Co(s) + PbCl 2(aq) ‡‡ˆ CoCl 2(aq) + Pb(s)
Which statement correctly describes the oxidation and reduction that occur?
A) Co(s) is reduced and Cl -(aq) is oxidized.
C) Co(s) is oxidized and Pb2+(aq) is reduced.
B) Co(s) is reduced and Pb2+(aq) is oxidized.
D) Co(s) is oxidized and Cl -(aq) is reduced.
22) In the reaction
3Cl 2 + 6NaOH ‡‡ˆ 5NaCl + NaClO3 + 3H2O
Cl 2 undergoes
A) neither oxidation nor reduction
B) both oxidation and reduction
C) reduction, only
D) oxidation, only
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23) Which half-reaction shows both the conservation of mass and the conservation of charge?
A) Br- ‡‡ˆ Br2 + 2e-
C) 2Br- + 2e- ‡‡ˆ Br2
B) Cl 2 ‡‡ˆ Cl - + 2e-
D) Cl 2 + 2e- ‡‡ˆ 2Cl -
24) Which change occurs when an Sn2+ ion is oxidized?
A) Two electrons are gained.
B) Two protons are lost.
C) Two electrons are lost.
D) Two protons are gained.
25) As an S2- ion is oxidized to an S0 atom, the number of protons in its nucleus
A) increases
B) decreases
C) remains the same
26) In the reaction Ni + CuSO4 ‡‡ˆ Cu + NiSO4, each nickel atom
A) gains one electron, only
B) loses two electrons
C) loses one electron, only
D) gains two electrons
27) Given the reaction:
2Na + 2H2O ‡‡ˆ 2Na+ + 2OH- + H2
Which substance is oxidized?
A) Na
B) H+
C) H
D) Na+
28) Given the equation for the discharge of a lead-acid battery:
Pb + PbO2 + 2H2SO4 ‡‡ˆ 2PbSO4 + 2H2O
Which substance is oxidized?
A) H2SO4
B) Pb
C) PbSO4
D) PbO2
29) Which half-cell reaction correctly represents oxidation?
A) Pb ‡‡ˆ Pb2+ + 2e-
C) Pb2+ ‡‡ˆ Pb + 2e-
B) Pb + 2e- ‡‡ˆ Pb2+
D) Pb2+ + 2e- ‡‡ˆ Pb
30) Which species is produced when a hydrogen atom is oxidized?
B)
A)
31)
C)
D)
C) gains 1 proton
D) gains 1 electron
When Fe3+ is reduced to Fe2+, the Fe3+ ion
A) loses 1 proton
B) loses 1 electron
32) Given the reaction:
2KCl(l) ‡‡ˆ 2K(s) + Cl 2(g)
In this reaction, the K+ ions are
A) reduced by gaining electrons
B) reduced by losing electrons
C) oxidized by gaining electrons
D) oxidized by losing electrons
33) In the reaction MnO2 + 4HCl ‡‡ˆ MnCl 2 + 2H2O + Cl 2, which species is reduced?
A) O2-
B) Mn4+
C) H+
D) Cl -
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34) Given the reaction:
Sn4+ + 2e- ‡‡ˆ Sn2+
This reaction can be classified as
A)
B)
C)
D)
an oxidation reaction, because there is an increase in oxidation number
a reduction reaction, because there is an increase in oxidation number
a reduction reaction, because there is a decrease in oxidation number
an oxidation reaction, because there is a decrease in oxidation number
35) Given the unbalanced equation:
__Fe + __Ag+ ‡‡ˆ __Ag + __Fe3+
When the equation is correctly balanced using smallest whole numbers, the coefficient of Ag+ is
A) 4
B) 5
C) 2
D) 3
36) Given the unbalanced equation:
__MnO2 + __HCl ‡‡ˆ MnCl 2 + H2O + Cl 2
When the equation is correctly balanced using smallest whole-number coefficients, the coefficient of HCl is
A) 4
B) 3
C) 1
D) 2
37) Given the unbalanced equation:
__Mg(s) + __Fe3+ ‡‡ˆ __Mg2+ + Fe(s)
When the equation is completely balanced using smallest whole numbers, the coefficient of Mg(s) will be
A) 1
B) 2
C) 3
D) 4
38) When the equation
Hg + __Ag+ ‡‡ˆ __Ag + Hg2+
is correctly balanced using smallest whole numbers, the coefficient in front of the Ag+ will be
A) 2
B) 4
C) 5
D) 3
39) When the equation
HNO3 + MnCl 2 + HCl ‡‡ˆ NO + MnCl 4 + H2O
is completely balanced using the smallest whole number coefficients, the coefficient of the HCl will be
A) 5
B) 2
C) 6
D) 3
40) When the equation NH3 + O2 ‡‡ˆ N2 + H2O is completely balanced using the smallest whole numbers, the
coefficient of the N2 will be
A) 4
B) 1
C) 2
D) 3
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41)
When the equation
__NO3- + 4H+ + __Cu ‡‡ˆ __Cu2+ + __NO2 + 2H2O
is correctly balanced, the coefficient of NO3- is
A) 1
B) 2
C) 4
D) 3
42) Which reduction half-reaction is correctly balanced?
A) Cl 2(g) + 2e- ‡‡ˆ Cl -
C) Cl 2(g) + 2e- ‡‡ˆ 2Cl -
B) Cl 2(g) + e- ‡‡ˆ 2Cl -
D) Cl 2(g) + e- ‡‡ˆ Cl -
43) Which redox equation is correctly balanced?
A) Sn4+ + H2 ‡‡ˆ Sn + 2H+
C) Cr3+ + Mg ‡‡ˆ Cr + Mg2+
B) Al 3+ + K ‡‡ˆ Al + K+
D) Br2 + Hg ‡‡ˆ Hg2+ + 2Br-
44) Which redox equation is correctly balanced?
A) Al + 2H+ ‡‡ˆ Al 3+ + H2
C) Cr + Ag+ ‡‡ˆ Cr3+ + Ag
B) Zn + 2H+ ‡‡ˆ Zn2+ + H2
D) Cu + Ag+ ‡‡ˆ Cu2+ + Ag
45) Given the unbalanced equation which represents aluminum metal reacting with an acid:
Al + H+ ‡‡ˆ Al +3 + H2
What is the total number of moles of electrons lost by 1 mole of aluminum?
A) 3
B) 13
C) 6
D) 2
46) Given the equation:
3Cu + 8HNO3 ‡‡ˆ 3Cu(NO3)2 + 2NO + 4H2O
What is the total number of moles of electrons lost by the copper as it completely reacts with 8 moles of nitric
acid?
A) 1
B) 4
C) 8
D) 6
47) Given the overall cell reaction:
Zn(s) + 2Ag+(aq) ‡‡ˆ Zn+2(aq) + 2Ag(s)
Which will occur as the cell operates?
A) The concentration of Ag+(aq) will increase.
C) The amount of Zn(s) will increase.
B) The amount of Ag(s) will decrease.
D) The concentration of Zn+2(aq) will increase.
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Questions 48 and 49 refer to the following:
The diagram below represents an electrochemical cell.
48) Which statement correctly describes the direction of flow for the ions in this cell when the switch is closed?
A)
B)
C)
D)
Ions move through the salt bridge in both directions.
Ions move through the salt bridge from B to C, only.
Ions move through the salt bridge from C to B, only.
Ions do not move through the salt bridge in either direction.
49) When the switch is closed, which group of letters correctly represents the direction of electron flow?
A) A ‚ F ‚ E ‚ D
B) A ‚ B ‚ C ‚ D
C) D ‚ C ‚ B ‚ A
D) D ‚ E ‚ F ‚ A
50) Which reaction will take place spontaneously?
51)
A) Cu + 2H+ ‡‡ˆ Cu2+ + H2
C) 2Ag + 2H+ ‡‡ˆ 2Ag+ + H2
B) Pb + 2H+ ‡‡ˆ Pb2+ + H2
D) 2Au + 6H+ ‡‡ˆ 2Au3+ + 3H2
Which metal will react with HCl(aq) to produce hydrogen gas?
A) Cu
B) Au
C) Zn
D) Hg
52) At 298 K, which metal will release H2(g) when reacted with HCl(aq)?
A) Ag(s)
B) Au(s)
C) Hg(l)
D) Zn(s)
53) Which reaction occurs when a strip of magnesium metal is placed in a solution of CuCl2?
A) The chloride ion is oxidized.
B) The magnesium metal is reduced.
C) The magnesium metal is oxidized.
D) The chloride ion is reduced.
54) Which ion is most easily oxidized?
A) Cl -
B) I-
C) Br-
D) F-
B) Zn2+
C) Ca2+
D) Cu2+
55) Which ion will oxidize Fe?
A) Mg2+
56) What is the purpose of the salt bridge in an electrochemical cell?
A) It allows ion migration.
B) It prevents electron flow.
C) It prevents ion migration.
D) It allows electron flow.
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57) The diagram below represents an electrochemical cell.
When switch S is closed, which particles undergo reduction?
A) Cu2+ ions
B) Zn atoms
C) Zn2+ ions
58) The diagram below represents a chemical cell at 298 K.
When the switch is closed, electrons flow from
A) Al 3+(aq) to Ni2+(aq)
C) Ni(s) to Al(s) Al to Ni
B) Al(s) to Ni(s)
D) Ni2+(aq) to Al 3+(aq)
D) Cu atoms
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59) The diagram below represents a chemical cell at 298 K.
In the given reaction, the Ag+ ions
A) gain protons
B) lose protons
C) lose electrons
D) gain electrons
60) In which kind of cell are the redox reactions made to occur by an externally applied electrical current?
A) galvanic cell
B) electrolytic cell
61)
C) electrochemical cell
D) chemical cell
An electrolytic cell differs from an electrochemical cell in that the electrolytic cell
A) produces an electric current
B) is exothermic
C) uses an applied electric current
D) involves redox
62) The number of electrons moving in a wire is measured in
A) volts
B) calories
C) ampheres
D) degrees
63) In an electrolytic cell, to which electrode will a positive ion migrate and undergo reduction?
A) the cathode, which is negatively charged
B) the anode, which is positively charged
C) the cathode, which is positively charged
D) the anode, which is negatively charged
64) Which statement best describes the reaction represented by the equation below?
2NaCl + 2H2O + electricity ‡‡ˆ Cl 2 + H2 + 2NaOH
A)
B)
C)
D)
The
The
The
The
reaction
reaction
reaction
reaction
occurs in
occurs in
occurs in
occurs in
a chemical cell and releases energy.
an electrolytic cell and absorbs energy.
a chemical cell and absorbs energy.
an electrolytic cell and releases energy.
65) In an electrolytic cell, oxidation takes place at the
A) anode, which is negative
B) cathode, which is positive
C) anode, which is positive
D) cathode, which is negative
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66) The diagram below represents an electroplating arrangement.
In the setup shown, an object to be plated with metal would be the
A) cathode at B
B) anode at B
C) cathode at A
D) anode at A
67) The diagram below represents the electroplating of a metal fork with Ag(s).
Which part of the electroplating system is provided by the fork?
A) the anode, which is the negative electrode
B) the cathode, which is the negative electrode
C) the cathode, which is the positive electrode
D) the anode, which is the positive electrode
68) Which half-reaction occurs at the cathode in an electrolytic cell in which an object is being plated with copper?
A) Cu2+ + 2e- ‡‡ˆ Cu(s)
C) Cu(s) ‡‡ˆ Cu2+ + 2e-
B) Cu(s) + 2e- ‡‡ˆ Cu2+
D) Cu2+ ‡‡ˆ Cu(s) + 2e-
69) Given the equation for the electrolysis of a fused salt:
LiCl(l) + electricity ‡‡ˆ 2Li(l) + Cl 2(g)
Which reaction occurs at the cathode?
A) Li+ ‡‡ˆ Li(l) + e-
C) Li+ + e- ‡‡ˆ Li(l)
B) 2Cl - ‡‡ˆ Cl 2(g) + 2e-
D) 2Cl - + 2e- ‡‡ˆ Cl 2(g)