Question 1

Potassium superoxide, KO2(s), is used in the breathing systems of biohazard suits.Write separate chemical equations showing how KO2(s)reacts with moisture and carbon dioxide in exhaled air to generate oxygen gas.

Accepted Answer

2KO₂(s)+ 2H₂O(l)

2KOH(a...

Question 2

How much energy (kJ) is released if 10.0g of Al(s) is reacted with excess Fe2O3(s) in the thermite reaction: 2Al(s) + Fe2O3(s)  →\rarr→  Al2O3(s) + 2Fe(l)  Δ\DeltaΔ H° = - 822.8 kJ/mol

Accepted Answer

A)  8,230 kJ
B)  823 kJ
C)  305 kJ
D)  152 kJ
E)  4,110 kJ F) A) and B)
G) A) and C) D

Question 3

Calcium metal is produced by electrolysis of

Accepted Answer

A)  CaSO4
B)  CaF2
C)  CaCO3
D)  Ca(OH) 2
E)  CaCl2F) A) and C)
G) B) and D)

Question 4

Which of the following diagrams represents a semiconductor?

Accepted Answer

A)  A
B)  B
C)  CD) All of the above
E) B) and C)

Question 5

The following reaction is used to produce titanium metal at high temperature.
TiCl4(g)+ 2Mg(l)$\rarr$Ti(s)+ 2MgCl2(l)
Which element is oxidized and which is reduced?

Accepted Answer

titanium is reduced ...

Question 6

Which of these ions is most likely to substitute for Ca2+ in the human body?

Accepted Answer

A)  Cl-
B)  Sr2+
C)  K+
D)  S2-
E)  Pb2+F) B) and C)
G) All of the above

Question 7

Beryllium, the first element in Group 2A, is the most metallic element in the group.

Accepted Answer

A) True 
 B)False

Question 8

Which one of these elements has seawater as its commercial source?

Accepted Answer

A)  Mg
B)  Al
C)  Ca
D)  Sn
E)  CdF) C) and D)
G) A) and B)

Question 9

Volatile impurities are removed from ores by means of

Accepted Answer

A)  roasting.
B)  amalgamation.
C)  electrolysis.
D)  flotation.
E)  zone refining.F) A) and B)
G) A) and C)

Question 10

The naturally occurring form of a metal that is concentrated enough to allow economical recovery of the metal is know as

Accepted Answer

A)  an element.
B)  a mineral.
C)  gangue.
D)  an ore.
E)  an amalgam.F) B) and E)
G) C) and E)

Question 11

Write two balanced chemical equations for the burning of magnesium in air.

Accepted Answer

2Mg(s)+ O₂(...

Question 12

For the reaction 3Fe(s) + C(s)   Fe3C(s) ,  \Delta H° = 21 kJ/mol and  \Delta S° = 20.4 J/mol·K at 25°C.Estimate the minimum temperature above which the formation of cementite (Fe3C) is favored. A) 1.0°C B) 970°C C) 700°C D) 1000°C E) 760°C " class="answers-bank-image d-inline" rel="preload" >  Fe3C(s) ,  Δ\DeltaΔ H° = 21 kJ/mol and  Δ\DeltaΔ S° = 20.4 J/mol·K at 25°C.Estimate the minimum temperature above which the formation of cementite (Fe3C) is favored.

Accepted Answer

A)  1.0°C
B)  970°C
C)  700°C
D)  1000°C
E)  760°C F) B) and D)
G) A) and B)

Question 13

How much energy (kJ) is released when 15.0g of Fe(l) is produced in the thermite reaction: 2Al(s) + Fe2O3(s)  →\rarr→  Al2O3(s) + 2Fe(l)  Δ\DeltaΔ H° = - 822.8 kJ/mol

Accepted Answer

A)  12,300 kJ
B)  221 kJ
C)  110.kJ
D)  6,170 kJ
E)  54.8 kJ F) B) and E)
G) B) and D)

Question 14

Which one of these metals would normally be obtained by electrolytic reduction?

Accepted Answer

A)  aluminum
B)  chromium
C)  copper
D)  iron
E)  zincF) C) and D)
G) B) and D) A

Question 15

What is the total number of moles (n) of electrons exchanged between the oxidizing agent and the reducing agent in the reaction below to obtain chromium metal: Cr2O3(s) + 2Al(s)  →\rarr→  2Cr(l) + Al2O3(s)

Accepted Answer

A)  1
B)  2
C)  3
D)  6
E)  21 F) C) and D)
G) B) and C)

Question 16

The principal reducing agent in a blast furnace is

Accepted Answer

A)  CaO(s) 
B)  CaSiO3(l) 
C)  CO(g) 
D)  O2(g) 
E)  CO2(g) F) C) and D)
G) A) and C)

Question 17

Bauxite (Al2O3·2H2O)ore is the principal commercial source of aluminum metal.

Accepted Answer

A) True 
 B)False

Question 18

The equilibrium 3Fe(s) + C(s)   Fe3C(s) is established in a solid solution.For such a solution, one can write an equilibrium constant expression in the usual way except that the concentrations that refer to solids in the solid solution are included.Determine the equilibrium constant for the formation of cementite from iron and carbon at 680°C.(Given: for this reaction at 25°C,  \Delta H° = 21 kJ/mol and  \Delta S° = 20.4 J/mol·K)  A) 0.75 B) 0.33 C) 3.1 D) 0.82 E) 1.2 " class="answers-bank-image d-inline" rel="preload" >  Fe3C(s) is established in a solid solution.For such a solution, one can write an equilibrium constant expression in the usual way except that the concentrations that refer to solids in the solid solution are included.Determine the equilibrium constant for the formation of cementite from iron and carbon at 680°C.(Given: for this reaction at 25°C,  Δ\DeltaΔ H° = 21 kJ/mol and  Δ\DeltaΔ S° = 20.4 J/mol·K)

Accepted Answer

A)  0.75
B)  0.33
C)  3.1
D)  0.82
E)  1.2 F) A) and E)
G) All of the above

Question 19

Write the chemical formula of pyrite.

Accepted Answer

FeS<sub>2</sub>

Question 20

In n-type semiconductors

Accepted Answer

A)  the energy gap between the valence band and the conduction band is very large.
B)  impurities that donate electrons are added to provide conduction electrons.
C)  a valence band overlaps the empty conduction band.
D)  impurities that provide "positive holes" are added to a pure semiconductor.E) A) and D)
F) B) and C)

Exam 21: Metallurgy and the Chemistry of Metals

Potassium superoxide, KO₂(s), is used in the breathing systems of biohazard suits.Write separate chemical equations showing how KO₂(s)reacts with moisture and carbon dioxide in exhaled air to generate oxygen gas.

Correct Answer
verified
2KO₂(s)+ 2H₂O(l)2KOH(a...
View Answer

How much energy (kJ) is released if 10.0g of Al(s) is reacted with excess Fe₂O₃(s) in the thermite reaction: 2Al(s) + Fe₂O₃(s) $\rarr$ Al₂O₃(s) + 2Fe(l) $\Delta$ H° = - 822.8 kJ/mol

Correct Answer
verified
D

Calcium metal is produced by electrolysis of

Correct Answer
verified

Which of the following diagrams represents a semiconductor?

Correct Answer
verified

The following reaction is used to produce titanium metal at high temperature. TiCl₄(g)+ 2Mg(l) $\rarr$ Ti(s)+ 2MgCl₂(l) Which element is oxidized and which is reduced?

Correct Answer
verified
titanium is reduced ...
View Answer

Which of these ions is most likely to substitute for Ca²⁺ in the human body?

Correct Answer
verified

Beryllium, the first element in Group 2A, is the most metallic element in the group.

Correct Answer
verified

Which one of these elements has seawater as its commercial source?

Correct Answer
verified

Volatile impurities are removed from ores by means of

Correct Answer
verified

The naturally occurring form of a metal that is concentrated enough to allow economical recovery of the metal is know as

Correct Answer
verified

Write two balanced chemical equations for the burning of magnesium in air.

Correct Answer
verified
2Mg(s)+ O₂(...
View Answer

Correct Answer
verified

How much energy (kJ) is released when 15.0g of Fe(l) is produced in the thermite reaction: 2Al(s) + Fe₂O₃(s) $\rarr$ Al₂O₃(s) + 2Fe(l) $\Delta$ H° = - 822.8 kJ/mol

Correct Answer
verified

Which one of these metals would normally be obtained by electrolytic reduction?

Correct Answer
verified
A

What is the total number of moles (n) of electrons exchanged between the oxidizing agent and the reducing agent in the reaction below to obtain chromium metal: Cr₂O₃(s) + 2Al(s) $\rarr$ 2Cr(l) + Al₂O₃(s)

Correct Answer
verified

The principal reducing agent in a blast furnace is

Correct Answer
verified

Bauxite (Al₂O₃·2H₂O)ore is the principal commercial source of aluminum metal.

Correct Answer
verified

Correct Answer
verified

Write the chemical formula of pyrite.

Correct Answer
verified
FeS₂

In n-type semiconductors

Correct Answer
verified

Exam 21: Metallurgy and the Chemistry of Metals

Potassium superoxide, KO2(s), is used in the breathing systems of biohazard suits.Write separate chemical equations showing how KO2(s)reacts with moisture and carbon dioxide in exhaled air to generate oxygen gas.

Correct Answerverified2KO2(s)+ 2H2O(l)2KOH(a...View AnswerShow Answer

How much energy (kJ) is released if 10.0g of Al(s) is reacted with excess Fe2O3(s) in the thermite reaction: 2Al(s) + Fe2O3(s) →\rarr→ Al2O3(s) + 2Fe(l) Δ\DeltaΔ H° = - 822.8 kJ/mol

Correct AnswerverifiedD

Calcium metal is produced by electrolysis of

Correct AnswerverifiedShow Answer

Which of the following diagrams represents a semiconductor?

Correct AnswerverifiedShow Answer

The following reaction is used to produce titanium metal at high temperature. TiCl4(g)+ 2Mg(l) →\rarr→ Ti(s)+ 2MgCl2(l) Which element is oxidized and which is reduced?

Correct Answerverifiedtitanium is reduced ...View AnswerShow Answer

Which of these ions is most likely to substitute for Ca2+ in the human body?

Correct AnswerverifiedShow Answer

Beryllium, the first element in Group 2A, is the most metallic element in the group.

Correct AnswerverifiedShow Answer

Which one of these elements has seawater as its commercial source?

Correct AnswerverifiedShow Answer

Volatile impurities are removed from ores by means of

Correct AnswerverifiedShow Answer

The naturally occurring form of a metal that is concentrated enough to allow economical recovery of the metal is know as

Correct AnswerverifiedShow Answer

Write two balanced chemical equations for the burning of magnesium in air.

Correct Answerverified2Mg(s)+ O2(...View AnswerShow Answer

For the reaction 3Fe(s) + C(s) Fe3C(s) , Δ\DeltaΔ H° = 21 kJ/mol and Δ\DeltaΔ S° = 20.4 J/mol·K at 25°C.Estimate the minimum temperature above which the formation of cementite (Fe3C) is favored.

Correct AnswerverifiedShow Answer

How much energy (kJ) is released when 15.0g of Fe(l) is produced in the thermite reaction: 2Al(s) + Fe2O3(s) →\rarr→ Al2O3(s) + 2Fe(l) Δ\DeltaΔ H° = - 822.8 kJ/mol

Correct AnswerverifiedShow Answer

Which one of these metals would normally be obtained by electrolytic reduction?

Correct AnswerverifiedA

What is the total number of moles (n) of electrons exchanged between the oxidizing agent and the reducing agent in the reaction below to obtain chromium metal: Cr2O3(s) + 2Al(s) →\rarr→ 2Cr(l) + Al2O3(s)

Correct AnswerverifiedShow Answer

The principal reducing agent in a blast furnace is

Correct AnswerverifiedShow Answer

Bauxite (Al2O3·2H2O)ore is the principal commercial source of aluminum metal.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Write the chemical formula of pyrite.

Correct AnswerverifiedFeS2

In n-type semiconductors

Correct AnswerverifiedShow Answer

Potassium superoxide, KO₂(s), is used in the breathing systems of biohazard suits.Write separate chemical equations showing how KO₂(s)reacts with moisture and carbon dioxide in exhaled air to generate oxygen gas.

Correct Answer
verified
2KO₂(s)+ 2H₂O(l)2KOH(a...
View Answer

How much energy (kJ) is released if 10.0g of Al(s) is reacted with excess Fe₂O₃(s) in the thermite reaction: 2Al(s) + Fe₂O₃(s) $\rarr$ Al₂O₃(s) + 2Fe(l) $\Delta$ H° = - 822.8 kJ/mol

Correct Answer
verified
D

Correct Answer
verified

Correct Answer
verified

The following reaction is used to produce titanium metal at high temperature. TiCl₄(g)+ 2Mg(l) $\rarr$ Ti(s)+ 2MgCl₂(l) Which element is oxidized and which is reduced?

Correct Answer
verified
titanium is reduced ...
View Answer

Which of these ions is most likely to substitute for Ca²⁺ in the human body?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
2Mg(s)+ O₂(...
View Answer

Correct Answer
verified

How much energy (kJ) is released when 15.0g of Fe(l) is produced in the thermite reaction: 2Al(s) + Fe₂O₃(s) $\rarr$ Al₂O₃(s) + 2Fe(l) $\Delta$ H° = - 822.8 kJ/mol

Correct Answer
verified

Correct Answer
verified
A

What is the total number of moles (n) of electrons exchanged between the oxidizing agent and the reducing agent in the reaction below to obtain chromium metal: Cr₂O₃(s) + 2Al(s) $\rarr$ 2Cr(l) + Al₂O₃(s)

Correct Answer
verified

Correct Answer
verified

Bauxite (Al₂O₃·2H₂O)ore is the principal commercial source of aluminum metal.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
FeS₂

Correct Answer
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