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Chemistry Problems

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Question 1
Consider an electrochemical cell constructed from the following half cells, linked by an external circuit and by a KCl salt bridge:

an Al(s) electrode in 1.0 M Al(NO3)3 solution
a Pb(s) electrode in 1.0 M Pb(NO3)2 solution

What is the balanced overall (net) cell reaction?

Pb(s) + Al3+(aq) Pb2+(aq) + Al(s)
3Pb(s) + 2Al3+(aq) 3Pb2+(aq) + 2Al(s)
3Pb2+(aq) + 2Al(s) 3Pb(s) + 2Al3+(aq)
Pb2+(aq) + Al(s) Pb(s) + Al3+(aq)

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Question 2
Calculate the value of Eocell for the following reaction:

2Au(s) + 3Ca2+(aq) 2Au3+(aq) + 3Ca(s)

-4.37 V
-1.37 V
-11.6 V
1.37 V
4.37 V

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Question 3
An electrochemical cell based on the following reaction has a standard cell voltage (Eocell) of 0.48 V.

Sn(s) + Cu2+(aq) Sn2+(aq) + Cu(s)

What is the standard reduction potential of tin?

Sn2+(aq) + 2e- Sn(s)

-0.14 V
0.14 V
-0.82 V
0.82 V
None of the above

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Question 4
Which chemical species undergoes reduction according to the following cell diagram?

Sn | Sn2+ || NO3- (acid soln), NO(g) | Pt

Sn
Sn2+
NO3-
NO
Pt

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Question 5
In the following half equation, which is the oxidizing agent?

NO3-(aq) + 4H+(aq) + 3e- NO(g) + 2H2O

NO3-
H+
e-
NO
H2O

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Question 6
Which statement is true in regard to a spontaneous redox reaction?

Eored is always negative.
Eocell is always positive.
Eoox is always positive.
Eored is always positive.

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Question 7
Which of the following species is the strongest oxidizing agent under standard state conditions?

Ag+(aq)
H2(g)
H+(aq)
Cl2(g)
Al3+(aq)

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Question 8
Calculate the cell emf for the following reaction:

2Ag+(0.010 M) + H2(1 atm) 2Ag(s) + 2H+ (pH = 10.0)

1.04 V
1.27 V
0.92 V
0.56 V
0.80 V

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Question 9
A current of 2.50 A was passed through an electrolytic cell containing molten CaCl2 for 4.50 hours. How many moles of calcium metal should be deposited?

5.83 x 10-5 mol
0.210 mol
0.420 mol
0.840 mol
1.95 x 109 mol

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Question 10
How long will it take to produce 78 g of Al metal by the reduction of Al3+ in an electrolytic cell with a current of 2.0 A?

0.01 s
420 s
13 h
116 h
1.0 x 1012 s

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Question 11
According to the band theory, which of the following provide(s) an explanation for the high electrical conductivity of metals?

a partly filled conduction band
a valence band overlapping an empty conduction band
a filled valence band
a large gap between the valence band and the conduction band
1 and 2
1 and 3
3
3 and 4
4

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Question 12
Which one of the following elements would form p-type semiconductors when added to silicon crystals?

C
P
As
Ga
Mg

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Question 13
The electron configuration of an Fe2+ ion is ________.

[Ar]4s24d4
[Ar]4s23d6
[Ar]3d3
[Ar]3d5
[Ar]3d6

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Question 14
How many 3d electrons does a Mn2+ ion have?

1
2
3
4
5

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Question 15
In the complex ion [Fe(CN)6]4-, the oxidation number of Fe is ________.

+1
+2
+3
-4
+6

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Question 16
In the complex ion [Co(en)2Br2]+, the oxidation number of Co is ________.

+1
+2
+3
-2
-1

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Question 17
A bidentate ligand always ________.

has bonds formed to two metal ions
has a charge of 2+ or 2-
forms complex ions with a charge of 2+ or 2-
has two donor atoms
has medical uses

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Question 18
Which one of the following is a monodentate ligand?

CN-
EDTA
C2O42- (oxalate ion)
H2NCH2CH2NH2 (ethylenediamine)

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Question 19
The best name for [Co(en)2Br2]Br is ________.

cobalt(III)bis(ethylenediamine) bromide
dibromobis(ethylenediamine)cobalt(III) bromide
dibromidedi(ethylenediamine)cobalt(III) bromide
dibromodiethylenediaaminecobalt(III) bromide
tribromobis(ethylenediamine)cobalt(III)

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Question 20
The correct formula for the dichlorobis(ethylenediamine)chromium(III) ion is ________.

[Cr(en)2Cl2]3+
[Cr(en)Cl2]+
[Cr(en)2Cl2]2+
[Cr(en)2Cl2]+
[Cr(en)3Cl2]+

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https://brainmass.com/chemistry/oxidation-reduction-and-electrochemistry/chemistry-problems-290919

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See Also This Related BrainMass Solution

Various Basic Chemistry Problems - Mole, Mass and other Calculations

1) When a mole of C2H4 is combusted it reacts with 3 moles of O2 to produce CO2 and H2O. How many moles of CO2 and how many moles of H2O are produced?

2) What is the mass in grams of 4.25 moles of Mg (NO3)2?

3) The overall reaction producing iron from an ore in a blast furnace is:

Fe2O3 + 3CO --> 2Fe + 3CO2

How many grams of Fe are produced when 275g of Fe2O3 react?

4) Using the bond energy table on page 190 of the text, determine the value of DH for the following reaction:

2F-F + O=O --> 2F-O-F

5) Giving reasons for your answers characterize the following compounds as saturated, or unsaturated, or incapable of existence.

A. CH2 B. C10H22 C. C2H2 D. C2H8 E. C 3H6

6) Determine the empirical formula of the compound that is 87.42% N and 12.58% H by weight.

7) What monomer can be used in an addition polymerization to produce the Polymer Teflon that has a repeating structure as follows:

8) What is the molality of 225g of C6H12O6 in 505 g of H2O?

9) What is the freezing temperature of the solution in question 8?

10) How many joules of energy are needed to raise the temperature of 325.0g of water from 20.0oC to 95.0oC. The specific heat of water is 4.184J/g-oC.

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