Download Chemistry Handout 08 - (Redox)

Chemistry Handout 08 - (Redox)
7895 - 1 - Page 1
Name: ____________________________________________
1)
In which compound does chlorine have the highest oxidation number?
A) NaClO2
2)
B) +7
B) proton
B) positrons
D) HCl
C) +2
D) +6
C) ion
D) neutron
C) neutrons
D) protons
As a Ca atom undergoes oxidation to Ca2+, the number of neutrons in its nucleus
A) remains the same
7)
C) HClO
Which particles are gained and lost during a redox reaction?
A) electrons
6)
B) HClO2
The transfer of which particle is required for a redox reaction to occur?
A) electron
5)
D) NaClO4
What is the oxidation number of chromium in K2 Cr2 O7 ?
A) +12
4)
C) NaClO
In which substance does chlorine have an oxidation number of +1?
A) Cl2
3)
B) NaClO3
B) increases
C) decreases
Given the reaction:
Mg + CuSO4 ‡‡ˆ MgSO4 + Cu
Which equation represents the oxidation that takes place?
8)
A) Mg 2+ + 2e- ‡‡ˆ Mg
C) Mg ‡‡ˆ Mg 2+ + 2e-
B) Cu ‡‡ˆ Cu 2+ + 2e-
D) Cu 2+ + 2e- ‡‡ˆ Cu
Given the reaction:
Mg(s) + 2H+(aq) + 2Cl-(aq) ‚ Mg 2+(aq) + 2Cl-(aq) + H2 (g)
Which species undergoes oxidation?
A) H2 (g)
9)
B) H+(aq)
C) Cl-(aq)
D) Mg(s)
C) C(s)
D) C2+
C) Al + 3e- ‚ Al3+
D) Al ‚ Al3+ + 3e-
Given the equation:
C(s) + H2 O(g) ‚ CO(g) + H2 (g)
Which species undergoes reduction?
A) H+
10)
In any redox reaction, the substance that undergoes reduction will
A)
B)
C)
D)
11)
B) H2 (g)
gain electrons and have an increase in oxidation number
lose electrons and have an increase in oxidation number
gain electrons and have a decrease in oxidation number
lose electrons and have a decrease in oxidation number
Given the equation:
2Al + 3Cu 2+ ‚ 2Al3+ + 3Cu
What is the reduction half-reaction?
A) Cu 2+ ‚ Cu + 2e-
12)
B) Cu 2+ + 2e- ‚ Cu
When a neutral atom undergoes oxidation, the atom's oxidation state
A) decreases as it gains electrons
B) increases as it gains electrons
C) increases as it loses electrons
D) decreases as it loses electrons
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13)
Which equation shows conservation of charge?
A) Fe ‡‡ˆ Fe2+ + e-
14)
B) Fe ‡‡ˆ Fe2+ + 2e-
D) Fe + 2e- ‡‡ˆ Fe2+
Which statement is true for any electrochemical cell?
A) Reduction occurs at both the anode and the cathode.
B) Oxidation occurs at both the anode and the cathode.
15)
C) Fe + 2e- ‡‡ˆ Fe3+
C) Oxidation occurs at the anode, only.
D) Reduction occurs at the anode, only.
A diagram of a chemical cell and an equation are shown below.
When the switch is closed, electrons will flow from
A) the Pb(s) to the Cu(s)
B) the Cu 2+(aq) to the Cu(s)
16)
According to the Activity Series chemistry reference table, which of these metals will react most readily with 1.0 M HCl to
produce H2 (g)?
A) Zn
17)
B) K
C) Mg
D) Ca
C) fermentation
D) neutralization
Which process requires an external power source?
A) synthesis
18)
C) the Cu(s) to the Pb(s)
D) the Pb 2+(aq) to the Pb(s)
B) electrolysis
Given the reaction: 4Al(s) + 3O2 (g) ‚ 2Al2 O3 (s)
(a) Write the balanced oxidation half-reaction for this oxidation-reduction reaction.
(b) What is the oxidation number of oxygen in Al2 O3 ?
19)
State one difference between voltaic cells and electrolytic cells. [Include information about both types of cells in your answer.]
Questions 20 and 21 refer to the following:
Two chemistry students each combine a different metal with hydrochloric acid. Student A uses zinc, and hydrogen gas is readily
produced. Student B uses copper, and no hydrogen gas is produced.
20)
State one chemical reason for the different results of students A and B.
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21)
Using Activity Series chemistry reference table, identify another metal that will react with hydrochloric acid to yield hydrogen
gas.
Questions 22 through 27 refer to the following:
The redox reaction below occurs spontaneously in an electrochemical cell.
Zn + Cr3+ ‚ Zn 2+ + Cr
22)
Write the half-reaction for the reduction that occurs.
23)
Write the half-reaction for the oxidation that occurs.
24)
In the equation below, balance the equation using the smallest whole-number coefficients.
__Zn + __Cr3+ ‚ __Zn 2+ + __Cr
25)
Which species loses electrons and which species gains electrons?
26)
Which half-reaction occurs at the cathode?
27)
State what happens to the number of protons in a Zn atom when it changes to Zn 2+ as the redox reaction occurs.
Questions 28 through 30 refer to the following:
28)
On the given diagram, indicate with one or more arrows the direction of electron flow through the wire.
29)
Write an equation for the half-reaction that occurs at the zinc electrode in the given diagram.
30)
Explain the function of the salt bridge in the given diagram.