Question 1

Write the chemical formula of pyrite.

Accepted Answer

FeS<sub>2</sub>

Question 2

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

Accepted Answer

A) aluminum 
B) chromium 
C) copper 
D) iron 
E) zinc 
A) aluminum 
B) chromium 
C) copper 
D) iron 
E) zinc A

Question 3

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

Accepted Answer

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

Question 4

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 5

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)

Accepted Answer

A) 0.75 
B) 0.33 
C) 3.1 
D) 0.82 
E) 1.2 
A) 0.75 
B) 0.33 
C) 3.1 
D) 0.82 
E) 1.2

Question 6

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

Accepted Answer

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

Question 7

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

Question 8

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

Accepted Answer

A) True 
 B)False

Question 9

Calcium metal is produced by electrolysis of

Accepted Answer

A) CaSO4 
B) CaF2 
C) CaCO3 
D) Ca(OH)2 
E) CaCl2 
A) CaSO4 
B) CaF2 
C) CaCO3 
D) Ca(OH)2 
E) CaCl2

Question 10

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 
A) 1 
B) 2 
C) 3 
D) 6 
E) 21

Question 11

Which of the following diagrams represents a semiconductor?

Accepted Answer

A) A 
B) B 
C) C 
A) A 
B) B 
C) C

Question 12

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

Accepted Answer

A) True 
 B)False

Question 13

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+ 
A) Cl- 
B) Sr2+ 
C) K+ 
D) S2- 
E) Pb2+

Question 14

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

Question 15

Volatile impurities are removed from ores by means of

Accepted Answer

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

Question 16

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

Accepted Answer

A) Mg 
B) Al 
C) Ca 
D) Sn 
E) Cd 
A) Mg 
B) Al 
C) Ca 
D) Sn 
E) Cd

Question 17

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)@#LAT-DLM&2KOH(a

Question 18

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. 
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.

Question 19

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.

Accepted Answer

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

Question 20

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

Accepted Answer

2Mg(s)+ O₂(

Exam 21: Metallurgy and the Chemistry of Metals

Write the chemical formula of pyrite.

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

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

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?

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

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

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

Calcium metal is produced by electrolysis of

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)

Which of the following diagrams represents a semiconductor?

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

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

The principal reducing agent in a blast furnace is

Volatile impurities are removed from ores by means of

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

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.

In n-type semiconductors

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.

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

Chemistry: the Study of Change

Atoms, Molecules, and Ions

Mass Relationships in Chemical Reactions

Reactions in Aqueous Solutions

Gases

Thermochemistry

Quantum Theory and the Electronic Structure of Atoms

Periodic Relationships Among the Elements

Chemical Bonding I: Basic Concepts

Chemical Bonding Ii: Molecular Geometry and Hybridization of Atomic Orbitals

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

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Electrochemistry

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Nonmetallic Elements and Their Compounds

Transition Metal Chemistry and Coordination Compounds

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Filters

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

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?

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

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

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)

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

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.