Deck 22: The Elements in Nature and Industry

Question 1

The most abundant element in the Earth's crust is

A)H
B)Fe
C)Al
D)Si
E)O

Answer 1

O

Question 2

The bond energy in the hydrogen molecule (H₂) is greater than that of the tritium molecule (T₂).

Answer 2

False

Question 3

Carbon atoms in the carbon cycle spend most of their time in the oceans.

Answer 3

False

Question 4

What are the main mineral sources of phosphorus?

A)Phosphides
B)Phosphites
C)Phosphors
D)Phosphates
E)Elemental phosphorus

Question 5

Transition elements from the left side of the periodic table are generally found as

A)sulfides because they tend to give up bonding electrons and form crystals with high lattice energies with sulfur.
B)sulfides because their electronegativities favor formation of covalent bonds with the polarizable sulfide anion.
C)oxides because they tend to give up bonding electrons and form crystals with high lattice energies with oxygen.
D)oxides because oxygen, with its high electronegativity, forms strong covalent bonds with them.
E)the uncombined elements, because they are noble metals.

Question 6

When nitrogen undergoes atmospheric fixation, it enters the sea and land in the form of

A)NO.
B)NO ₂.
C)NH ₃.
D)NO ₃ ⁻ _.
E)NH ₄ ⁺ _.

Question 7

The purpose of anodizing aluminum is to remove the oxide layer from the metal's surface.

Question 8

The atmosphere contains about 700. billion metric tons of carbon in the form of carbon dioxide. In the carbon cycle, about 200. billion metric tons of carbon (as carbon dioxide) enters the atmosphere each year. Assuming that 200. billion metric tons of carbon also leaves the atmosphere annually, how many years does the average carbon atom spend in the atmosphere in each cycle?

A)0.29 years
B)3.5 years
C)500. years
D)140,000 years
E)More information is needed in order to calculate the answer.

Question 9

Nitrogen fixation occurs through atmospheric, industrial, and biological processes. Which of these fixes the most nitrogen?

A)Biological
B)Atmospheric
C)Industrial
D)Industrial ≈ Atmospheric
E)Industrial ≈ Biological

Question 10

Plants extract phosphate from the soil

A)by converting it to the dihydrogen phosphate ion by addition of acid to the soil near roots.
B)by converting it to phosphoric acid.
C)by osmosis.
D)by leaching.
E)by fixation.

Question 11

In the industrial electrolysis of aqueous NaCl (the chlor-alkali process), the modern trend is toward the use of cells incorporating polymer membranes to separate the anode and cathode solutions.

Question 12

The Earth's core consists mainly of

A)Ni
B)O
C)Al
D)Si
E)Fe

Question 13

The process in which a gaseous substance is converted into a condensed, more usable chemical substance is called

A)differentiation.
B)liquefaction.
C)fixation.
D)deposition.
E)remediation.

Question 14

In the electrolysis of water, the hydrogen gas evolved at the cathode is enriched in deuterium (hydrogen-2), compared to the more common isotope, protium (hydrogen-1).

Question 15

Sulfide ores are frequently treated by flotation in order to concentrate them.

Question 16

The most common source for commercial production of aluminum is called

A)aluminite.
B)hematite.
C)galena.
D)cinnabar.
E)bauxite.

Question 17

Transition elements from the right side of the periodic table are generally found as

A)sulfides because they tend to give up bonding electrons and form crystals with high lattice energies with sulfur.
B)sulfides because their electronegativities favor formation of covalent bonds with the polarizable sulfide anion.
C)oxides because they tend to give up bonding electrons and form crystals with high lattice energies with oxygen.
D)oxides because oxygen, with its high electronegativity, forms strong covalent bonds with them.
E)None of these choices are correct.

Question 18

The main effect of the biosphere on the chemistry of the Earth's crust has been to

A)create a reducing atmosphere.
B)create an oxidizing atmosphere.
C)increase the relative humidity.
D)decrease the relative humidity.
E)increase the level of atmospheric carbon dioxide.

Question 19

Hydrogen displays the largest kinetic isotope effect of all the elements.

Question 20

The industrial production of ammonia from nitrogen and hydrogen accounts for a greater amount of nitrogen fixation than either the atmospheric or the biological pathways.

Question 21

The __________ process uses a boiling 30% sodium hydroxide solution to treat bauxite.

A)Bayer
B)Hall-Heroult
C)Dow
D)Frasch
E)Haber

Question 22

The most common source for commercial production of sodium is called

A)sodalite.
B)limestone.
C)halite.
D)galena.
E)pyrite.

Question 23

What gas is produced during the Hall-Héroult process for production of aluminum?

A)Chlorine, Cl ₂
B)Oxygen, O ₂
C)Hydrogen, H ₂
D)Ammonia, NH ₃
E)Carbon dioxide, CO ₂

Question 24

The debris accompanying a mineral is called

A)slag.
B)gangue.
C)ore.
D)halite.
E)ash.

Question 25

The process of converting metal sulfides to metal oxides is called

A)roasting.
B)smelting.
C)reduction.
D)leaching.
E)oxidation.

Question 26

Calcium oxide is added to molten iron in the production of carbon steel in order to

A)convert silicon and phosphorus oxides to slag which can be decanted from the molten steel.
B)serve as a scrubber to remove sulfur dioxide from the gases leaving the furnace.
C)remove any traces of acid which could weaken the steel.
D)add a small amount of oxygen to the steel to prevent corrosion and increase its strength.
E)create gangue.

Question 27

Hydrometallurgy uses __________ to separate a metal from its ore.

A)solid phase chemical properties
B)electrical processes
C)thermal processes
D)aqueous chemical processes
E)molten salt processes

Question 28

Pyrometallurgy uses __________ to separate a metal from its ore.

A)solid phase chemical properties
B)electrical processes
C)thermal processes
D)aqueous chemical processes
E)explosives

Question 29

The process that selectively extracts a metal from its ore, by dissolving it, is called

A)roasting.
B)leaching.
C)smelting.
D)flotation.
E)hydration.

Question 30

Cryolite, Na₃AlF₆, is used in the electrolysis of aluminum oxide because

A)it is a good source of fluoride ions.
B)it reduces the energy requirement of the process, due to its low melting point.
C)it provides a source of fluorine, an oxidizing agent.
D)it provides a source of sodium, a reducing agent.
E)it is very soluble in water.

Question 31

Which one of the following species or compounds reacts at the cathode in the Hall-Héroult process?

A)Al ₂O ₃
B)Al(OH)₃
C)F ⁻
D)AlF ₆ ³⁻
E)C

Question 32

The Downs cell is used in the production of

A)copper.
B)hydrogen.
C)iron.
D)magnesium.
E)sodium.

Question 33

The final step of the purification of copper involves electrorefining in which copper is separated from nickel and iron by being reduced at the cathode of a cell. Why are nickel and iron not reduced?

A)Their reduction potentials are more positive than copper's.
B)Their reduction potentials are more negative than copper's.
C)They cannot be deposited on a copper electrode.
D)Their reduction potentials are more negative than water's.
E)Their reduction requires large overvoltages.

Question 34

Electrometallurgy uses __________ to separate a metal from its ore.

A)solid phase chemical properties
B)electrical processes
C)thermal processes
D)aqueous chemical processes
E)molten salt processes

Question 35

The alkali metals are isolated from non-aqueous systems. Why is this necessary?

A)The electrolysis of aqueous solutions of the alkali metals requires more energy than electrolysis of the molten salts.
B)The dissolved alkali earth halides are too reactive to be electrolyzed.
C)The aqueous metal ions are more difficult to reduce than water.
D)The reduction potentials of the alkali metals are more positive than the reduction potential of water.
E)The aqueous metal ions react violently with water.

Question 36

The kinetic isotope effect is the basis for

A)the radioactivity of tritium.
B)isolation of pure D ₂O.
C)tritium's high reactivity.
D)the increase in boiling point when comparing hydrogen, deuterium, and tritium.
E)nuclear power generation.

Question 37

The Hall-Heroult process refers to

A)the production of aluminum by electrolysis.
B)the recovery of sulfur from underground deposits.
C)the manufacture of sulfuric acid.
D)the production of ammonia from nitrogen and hydrogen gases.
E)the isolation of Al ₂O ₃ from bauxite.

Question 38

What elements are alloyed to make stainless steel?

A)Fe and C
B)Fe and Mn
C)Fe and Ni
D)Cr and C
E)Fe, Cr, and Ni

Question 39

The process used to produce silicon with a purity of more than 99.999999% is called

A)zone refining.
B)electrorefining.
C)distillation.
D)sublimation.
E)alloying.

Question 40

Alloying a metal is done to

A)make its extraction from its ore easier.
B)convert the metal to an oxide.
C)disguise the true identity of the metal.
D)prepare ultrapure metal samples.
E)enhance properties like conductivity.

Question 41

Sulfur trioxide is the anhydride of sulfuric acid. However, SO₃ is not added directly to water during the synthesis of sulfuric acid because

A)hydration of SO ₃ is very exothermic and difficult to control.
B)hydration of SO ₃ is very endothermic and proceeds too slowly to be profitable.
C)at high temperatures water vapor catalyzes polymerization of SO ₃.
D)vapor phase sulfuric acid is corrosive and limits the useful life of the reactor.
E)the water would decompose under such conditions.

Question 42

Electrolysis is used as the last step in isolating pure

A)iron.
B)boron.
C)aluminum.
D)selenium.
E)carbon.

Question 43

The chlor-alkali process produces chlorine, Cl₂(g), in large quantities. What other industrially important substances are produced in this process?

A)Na( s), H ₂( g)
B)H ₂( g), O ₂( g)
C)Hg( l), NaCl( s)
D)Na( s), O ₂( g)
E)NaOH( aq), H ₂( g)

Question 44

The Frasch process is used to

A)convert aluminum oxide to metallic aluminum.
B)convert copper ore to copper sulfide.
C)mine magnesium.
D)mine elemental sulfur.
E)produce sodium metal.

Question 45

Which of the following general process occurs when a mineral is roasted?

A)Metal sulfide is reduced to the metal
B)Metal oxide is reduced to the metal
C)Metal is converted to metal oxide
D)Metal sulfide is converted to metal oxide
E)Metal oxide dissolves in aqueous solution