Question 1

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) A) and D)
G) A) and E)

Question 2

Write the chemical formula of fluorite.

Accepted Answer

The answer of Write the chemical formula of fluorite....

Question 3

What effect does increasing temperature have on the conductivities of semiconductors?

Accepted Answer

A)  increases
B)  decreases
C)  no change
D)  cannot be predictedE) A) and D)
F) A) and C)

Question 4

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) B) and C)

Question 5

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 B)
F) A) and D)

Question 6

Cast iron as it is prepared in a blast furnace is a product of high purity.

Accepted Answer

A) True 
 B)False

Question 7

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) B) and C)

Question 8

Why is cryolite, Na3AlF6, mixed with alumina prior to electrolysis in the production of Al?

Accepted Answer

It acts is...

Question 9

Write the chemical formula of corundum.

Accepted Answer

The answer of Write the chemical formula of corundum....

Question 10

Which of these reactions represents the removal of silica from iron ore in a blast furnace?

Accepted Answer

A)  SiO2(s)  →	o→ SiO2(g) 
B)  SiO2(s) + CaO(s)  →	o→  CaSiO3(l) 
C)  SiO2(s) + 4HF(g)  →	o→  SiF4(g) + 2H2O(g) 
D)  SiO2(s) + C(s)  →	o→ Si(l) + CO2(g) 
E)  SiO2(s) + CO(g)  →	o→ SiCO3(l)  F) B) and C)
G) A) and B)

Question 11

In Al2Cl6, the geometry of the molecule at each aluminum atom is

Accepted Answer

A)  trigonal planar
B)  tetrahedral
C)  trigonal pyramidal
D)  square planar
E)  octahedralF) None of the above
G) D) and E)

Question 12

The Hall process involves the reduction of Al2O3 to aluminum by

Accepted Answer

A)  carbon (coke) .
B)  carbon monoxide.
C)  molecular hydrogen.
D)  sodium.
E)  electrolysis.F) A) and E)
G) A) and D)

Question 13

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) A) and B)
G) A) and C)

Question 14

Which one of these elements would give a p-type semiconductor when added to a silicon crystal?

Accepted Answer

A)  C
B)  P
C)  As
D)  Ga
E)  SbF) B) and D)
G) C) and D)

Question 15

In the Mond process, nickel is purified by

Accepted Answer

A)  dissolving the crude ore in sulfuric acid, and precipitating the nickel(II) ion as the sulfate salt.
B)  dissolving the crude ore in a lye (NaOH) solution, and precipitating the nickel(II) ion as the hydroxide salt.
C)  heating the crude ore to its melting point and electrolytically reducing the nickel(II) ions to form the metal.
D)  passing sodium gas over the crude ore at high temperatures, chemically reducing the nickel(II) to nickel metal.
E)  passing carbon monoxide over the impure metal at high temperature, forming the volatile Ni(CO) 4 which is removed as a gas.F) B) and C)
G) B) and D)

Question 16

In p-type semiconductors,

Accepted Answer

A)  the semiconductors are "ultra purified" to increase conductivity.
B)  the valence and conduction bands are formed exclusively from "p orbitals."
C)  the semiconductors are "patented" for use in commercial applications.
D)  acceptor impurities are added to provide "positive holes" that increase the electrical conductivity of the semiconductor.E) A) and B)
F) B) and C)

Question 17

The equilibrium 3Fe(s) + C(s)   Fe3C(s) is established in a solid solution. For such a solution, one can write an equilibrium constant in the usual way except that here one has concentrations that refer to solids in the solid solution. 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 in the usual way except that here one has concentrations that refer to solids in the solid solution. 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) B) and E)
G) B) and C)

Question 18

Which of these elements when doped into silicon would give an n-type semiconductor?

Accepted Answer

A)  C
B)  Ga
C)  P
D)  Ge
E)  BF) A) and C)
G) D) and E)

Question 19

According to the band theory, which of these statements provide(s) an explanation for the high electrical conductivity of metals? I.a partly filled conduction band
II.a valence band overlapping an empty conduction band
III.a filled valence band
IV.a large gap between the valence band and the conduction band

Accepted Answer

A)  I and II
B)  I and III
C)  III
D)  III and IV
E)  IVF) A) and E)
G) B) and E)

Question 20

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

Accepted Answer

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

Exam 20: Metallurgy and the Chemistry of Metals

What effect does increasing temperature have on the conductivities of semiconductors?

Correct Answer
verified

The principal reducing agent in a blast furnace is

Correct Answer
verified

Write the chemical formula of fluorite.

Correct Answer
verified

Which one of these elements would give a p-type semiconductor when added to a silicon crystal?

Correct Answer
verified

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

Correct Answer
verified

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

Correct Answer
verified

In n-type semiconductors

Correct Answer
verified

The Hall process involves the reduction of Al₂O₃ to aluminum by

Correct Answer
verified

Cast iron as it is prepared in a blast furnace is a product of high purity.

Correct Answer
verified

In the Mond process, nickel is purified by

Correct Answer
verified

In Al₂Cl₆, the geometry of the molecule at each aluminum atom is

Correct Answer
verified

In p-type semiconductors,

Correct Answer
verified

Volatile impurities are removed from ores by means of

Correct Answer
verified

Why is cryolite, Na₃AlF₆, mixed with alumina prior to electrolysis in the production of Al?

Correct Answer
verified
It acts is...
View Answer

Correct Answer
verified

Which of these elements when doped into silicon would give an n-type semiconductor?

Correct Answer
verified

Which of these reactions represents the removal of silica from iron ore in a blast furnace?

Correct Answer
verified

Write the chemical formula of corundum.

Correct Answer
verified

Exam 20: Metallurgy and the Chemistry of Metals

What effect does increasing temperature have on the conductivities of semiconductors?

Correct AnswerverifiedShow Answer

The principal reducing agent in a blast furnace is

Correct AnswerverifiedShow Answer

Write the chemical formula of fluorite.

Correct AnswerverifiedShow Answer

Which one of these elements would give a p-type semiconductor when added to a silicon crystal?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow 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

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

Correct AnswerverifiedShow Answer

In n-type semiconductors

Correct AnswerverifiedShow Answer

The Hall process involves the reduction of Al2O3 to aluminum by

Correct AnswerverifiedShow Answer

Cast iron as it is prepared in a blast furnace is a product of high purity.

Correct AnswerverifiedShow Answer

In the Mond process, nickel is purified by

Correct AnswerverifiedShow Answer

In Al2Cl6, the geometry of the molecule at each aluminum atom is

Correct AnswerverifiedShow Answer

In p-type semiconductors,

Correct AnswerverifiedShow Answer

Volatile impurities are removed from ores by means of

Correct AnswerverifiedShow Answer

Why is cryolite, Na3AlF6, mixed with alumina prior to electrolysis in the production of Al?

Correct AnswerverifiedIt acts is...View AnswerShow Answer

Correct AnswerverifiedShow Answer

Which of these elements when doped into silicon would give an n-type semiconductor?

Correct AnswerverifiedShow Answer

Which of these reactions represents the removal of silica from iron ore in a blast furnace?

Correct AnswerverifiedShow Answer

Write the chemical formula of corundum.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified

The Hall process involves the reduction of Al₂O₃ to aluminum by

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

In Al₂Cl₆, the geometry of the molecule at each aluminum atom is

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Why is cryolite, Na₃AlF₆, mixed with alumina prior to electrolysis in the production of Al?

Correct Answer
verified
It acts is...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified