AnswersTX-Chemistry BUnit Test

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The following equations are half reactions and reduction potentials. Li+ (aq) + e– Li(s) has a reduction potential of –3.04 V F2(g) + 2e– 2F–(aq) has a reduction potential of +2.87 VNow consider lithium (LI+) and fluoride (F2) as oxidizing agents. How do these compare as oxidizing agents?

Question illustration
A
Lithium is a stronger oxidizing agent than fluoride.
B
Fluoride is a stronger oxidizing agent than lithium.
C
Fluoride and lithium have the same oxidizing strength.
D
Reduction potential and oxidizing/reducing strength are unrelated.
2
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Which answer best describes what is happening in the following redox reaction?4Fe + 3O2 2Fe2O3

Question illustration
A
This is combustion.
B
This is neutralization.
C
Iron is oxidized to form rust.
D
Oxygen is oxidized to form rust.
3

Consider the half reaction below.Which statement best describes what is taking place?

Question illustration
A
Chlorine is losing electrons and being oxidized.
B
Chlorine is losing electrons and being reduced.
C
Chlorine is gaining electrons and being oxidized.
D
Chlorine is gaining electrons and being reduced.
4

What is the oxidation number for N in the compound NH3? (Recall that H usually has an oxidation number of +1.)

A
–3
B
–1
C
0
D
+3
5

The reaction below was carried out in an acidic solution.Which statement is true about this equation?

Question illustration
A
Although it is unbalanced, it can be balanced by using the half-reaction method.
B
It has been balanced by using the half-reaction method.
C
It has been balanced by directly using spectator ions.
D
Although it is unbalanced, it can be balanced by directly using spectator ions.
6

What must be true of a disproportionate substance?

A
It is composed of oxygen.
B
It is both a reactant and a product.
C
It has an oxidation number of 0.
D
It gains and loses electrons.
7

Which of the following is not an oxidation-reduction reaction?

A
XeF6(s) XeF4(s) + F2(g)
Option A
B
2Cs(s) + I2(g) 2CsI(s)
Option B
C
2H2SO4(aq) + 2Ba(OH)2(aq) 2BaSO4(s) + 4H2O(l)
Option C
D
Zn(s) + 2AgNO3(aq) Zn(NO3)2(aq) + Ag(s)
Option D
8

Consider the reaction below.What is being reduced?

Question illustration
A
only K
B
only Br2
C
both K and Br2
D
neither K nor Br2
9

Read the table below.Reduction Half-ReactionStandard Reduction Potential (V)What is the overall reaction potential for the reaction below?Ag+(aq) + Cu(s) Ag(s) + Cu2+(aq)

Question illustration
A
0.46 V
Option A
B
+0.46 V
C
+0.57 V
D
+1.14 V
10

Consider the half reactions below for a chemical reaction.What is the overall equation for this chemical reaction?

Question illustration
A
Upper Z n (s) plus upper C u superscript 2 plus (a q) right arrow upper Z n superscript 2 plus (a q) plus upper C u (s).
Option A
B
Upper Z n (s) plus upper C u superscript 2 plus (a q) right arrow upper C u superscript 2 plus (a q) plus upper Z n (s).
Option B
C
Upper Z n superscript 2 plus (a q) plus upper C u (s) right arrow upper C u superscript 2 plus (a q) plus upper Z n (s).
Option C
D
Upper Z n superscript 2 plus (a q) plus 2 e superscript minus right arrow upper C u superscript 2 plus (a q) plus 2 e superscript plus.
Option D
11

Which rule for assigning oxidation numbers is correct?

A
Hydrogen is usually –1.
B
Oxygen is usually –2.
C
A pure group 1 element is +1.
D
A monatomic ion is 0.
12

What describes the change in oxidation states of the following reaction?

Question illustration
A
Cu2+ reduces to Cu, and Al oxidizes to AI3+.
B
Cu2+ oxidizes to Cu, and Al reduces to AI3+.
C
Cu2+ is the reducing agent, and Al is the oxidizing agent.
D
Cu is the reducing agent, and AI3+ is the oxidizing agent.
13

Which of the following is a simple definition of oxidation?

A
the loss of electrons
B
the gain of electrons
C
an agent that oxidizes something
D
an agent that reduces something
14

The information below describes a redox reaction.What is the coefficient of silver in the final, balanced equation for this reaction?

Question illustration
A
1
B
2
C
3
D
4
15

What is the oxidation number for S in the compound SO3? (Recall that O has an oxidation number of –2.)

A
0
B
+2
C
+4
D
+6
16

What is the reducing agent in the following reaction? Cl2(aq) + 2Br(aq) 2Cl(aq) + Br2(aq)

Question illustration
A
Br2
B
CI2
C
Br-
D
CI-
17

Which identifies an oxidation-reduction reaction?

A
a double replacement reaction
B
a neutralization reaction
C
a reaction in which oxidation numbers change
D
a reaction in which no electrons are transferred
18

Read the table below.Reduction Half-ReactionStandard Reduction Potential (V)Which reactants would lead to a spontaneous reaction?

Question illustration
A
Mn2+ and Cr
B
Fe and Cu2+
C
Al and Ba2+
D
Mg2+ and Sn
19

Which type of reaction occurs in the following?2HgO(s) 2Hg(l) + O2(g)

Question illustration
A
a decomposition reaction in which a metal is reduced
B
an acid-base neutralization reaction to produce oxygen gas
C
a displacement reaction involving two metals
D
a combustion reaction involving burning a metal in oxygen
20

Which of the following is true about a redox reaction?

A
In a redox reaction, the reducing agent loses electrons.
B
In a redox reaction, the oxidizing agent loses electrons.
C
In a redox reaction, the oxidized species gains electrons.
D
In a redox reaction, the reduced species loses electrons.

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