Deck 12: Solids and Modern Materials

Question 1

What fraction of the volume of each corner atom is actually within the volume of a face-centered cubic unit cell?

A)1
B)1/2
C)1/4
D)1/8
E)1/16

Answer 1

1/8

Question 2

All of the following statements about steel are true except ________.

A)it is an alloy of iron
B)it can have different percentages of carbon
C)it is a monomer
D)it can be made so it resists rust
E)none of the above

Answer 2

it is a monomer

Question 3

What portion of the volume of each atom or ion on the face of a unit cell is actually within the unit cell?

A)1/2
B)1/4
C)3/4
D)all of it
E)none of it

Answer 3

1/2

Question 4

________ are examples of homogeneous alloys.

A)Covalent compounds
B)Interstitial compounds
C)Intermetallic compounds
D)Intrametallic compounds
E)Ionic compounds.

Question 5

For a substitutional alloy to form,the two metals combined must have similar ________.

A)ionization potential and electron affinity
B)number of valance electrons and electronegativity
C)reduction potential and size
D)atomic radii and chemical bonding properties
E)band gap and reactivity

Question 6

A metallic material that is composed of two or more elements is called a(n)________.

A)homogeneous mixture
B)pure metal
C)nonmetal
D)alloy
E)mineral

Question 7

The ________ of light waves upon passing through a narrow slit is called diffraction.

A)diffusion
B)scattering
C)grating
D)adhesion
E)incidence

Question 8

Of the following,________ may be added to steel to modify its properties.

A)carbon only
B)carbon and nickel
C)nickel only
D)copper only
E)none of the above

Question 9

All of the following are a type of solid except ________.

A)supercritical
B)ionic
C)molecular
D)covalent network
E)metallic

Question 10

________ have properties that depend on the manner in which the solid is formed.

A)Pure metals
B)Heterogeneous alloys
C)Homogeneous alloys
D)Pure alloys

Question 11

All of the following can form a solid with a lattice structure similar to that of sodium chloride except ________.

A)NaF
B)CuBr₂
C)LiCl
D)KI
E)MgO

Question 12

Crystalline solids differ from amorphous solids in that crystalline solids have ________.

A)appreciable intermolecular attractive forces
B)a long-range repeating pattern of atoms, molecules, or ions
C)atoms, molecules, or ions that are close together
D)much larger atoms, molecules, or ions
E)no orderly structure

Question 13

Metallic solids exhibit all of the following except ________.

A)thermal conductivity
B)brittleness
C)electrical conductivity
D)variable melting point
E)variable hardness

Question 14

Trends in melting points for metals can be explained with the ________.

A)intermolecular model
B)electron-sea model
C)thermal conductivity model
D)covalent bonding model
E)ionic bonding model

Question 15

A solid has a very high melting point,great hardness,and poor electrical conduction.This is a(n)________ solid.

A)ionic
B)molecular
C)metallic
D)covalent network
E)metallic and covalent network

Question 16

The unit cell with all sides the same length and all angles equal to 90° that has lattice points only at the corners is called ________.

A)monoclinic
B)body-centered cubic
C)primitive cubic
D)face-centered cubic
E)spherical cubic

Question 17

Consider the following statements about crystalline solids: (i)Molecules or atoms in molecular solids are held together via ionic bonds.
(ii)Metallic solids have atoms in the points of the crystal lattice.
(iii)Ionic solids have formula units in the point of the crystal lattice.
(iv)Molecules in covalent-network solids are connected via a network of covalent bonds.
Which of the statements is true?

A)(i)
B)(ii)
C)(iii)
D)(iv)
E)none

Question 18

________ generally differ from compounds in that the atomic ratios of the constituent elements in the former are ________ and may vary over a wide range.

A)Pure metals, fixed
B)Alloys, not fixed
C)Pure metals, not fixed
D)Alloys, fixed
E)Solids, not fixed

Question 19

The addition of an interstitial element to a metal ________ the overall hardness and strength while ________ the ductility.

A)decreases, increasing
B)increases, increasing
C)increases, decreasing
D)decreases, decreasing
E)Adding an interstitial element to a metal has no affect on its properties.

Question 20

Which one of the following is a property of most metals?

A)low melting point
B)brittleness
C)high electronegativity
D)thermal conductivity
E)acidic oxides

Question 21

NaCl crystallizes in a face-centered cubic cell.What is the total number of ions (Na⁺ ions and Cl^- ions)that lie within a unit cell of NaCl?

A)2
B)4
C)8
D)6
E)5

Question 22

The properties of graphene include ________.

A)large thermal conductivity
B)high strength
C)a zero energy gap
D)A and B
E)A, B and C

Question 23

An elastomer will fail to regain its original dimensions following a distortion beyond its ________.

A)glass transition
B)phase boundary
C)London force
D)crystallinity
E)elastic limit

Question 24

Natural rubber is too soft and chemically reactive for practical applications.________ of natural rubber entails crosslinking reactive polymer chains with sulfur atoms.

A)Addition
B)Conversion
C)Vulcanization
D)Condensation
E)Polymerization

Question 25

CsCl crystallizes in a unit cell that contains the Cs⁺ ion at the center of a cube that has a Cl^- at each corner.Each unit cell contains ________ Cs⁺ ion(s)and ________ Cl^- ion(s),respectively.

A)1, 8
B)2, 1
C)1, 1
D)2, 2
E)2, 4

Question 26

Which one of the following is an addition polymer with the same structure as polyethylene except that one hydrogen on every other carbon is replaced by a benzene ring?

A)polyvinyl alcohol
B)polystyrene
C)polyethylene
D)polyethylene glycol
E)Teflon

Question 27

An unknown metal crystallizes in a body-centered cubic structure with a unit cell edge length of 4.35 Å.The radius of the unknown atom is ________ Å.

A)1.88
B)3.77
C)2.18
D)8.70
E)4.35

Question 28

The ________ for Ge shows it to be a semiconductor,because the gap between the filled lower and empty higher energy bands is relatively small.

A)molecular-orbital model
B)quantum mechanics model
C)atomic-orbital model
D)valence bond model
E)intermolecular model

Question 29

All of the following are classified as a nanomaterial except ________.

A)carbon nanotubes
B)buckminsterfullerene
C)isoprene
D)graphene
E)All of the above are classified as nanomaterials

Question 30

What happens to a polymer as it becomes more crystalline?

A)its melting point decreases
B)its density decreases
C)its yield stress decreases
D)its stiffness decreases
E)None of the above is correct.

Question 31

How many valence electrons do inorganic compounds contain if they are considered semiconductors?

A)2
B)1
C)4
D)5
E)3

Question 32

The formation of a ________ polymer generally involves the elimination of a small molecule.

A)conversion
B)vulcanization
C)monomeric
D)condensation
E)polymerization

Question 33

An unknown metal crystallizes in a primitive cubic unit cell.The length of the unit cell edge is 2.85 Å.The radius of the unknown atom is ________ Å.

A)5.70
B)1.43
C)1.85
D)1.01
E)Insufficient data is given.

Question 34

If the electronic structure of a solid substance consists of a valence band that is completely filled with electrons and there is a large energy gap to the next set of orbitals,then this substance will be a(n)________.

A)alloy
B)insulator
C)conductor
D)semiconductor
E)nonmetal

Question 35

Molecular solids consist of atoms or molecules held together by ________.

A)dipole-dipole forces only
B)Metallic bonds only
C)London dispersion forces and hydrogen bonds only
D)hydrogen bonds only
E)dipole-dipole forces, London dispersion forces, and/or hydrogen bonds

Question 36

The process of ________ can produce an n-type semiconductor,which can greatly increase intrinsic conductivity.

A)melting
B)fusing
C)doping
D)mixing
E)infusing

Question 37

CsCl crystallizes in a unit cell that contains a Cs⁺ ion at the center of a cube and a Cl^- ion at each corner.The unit cell of CsCl is ________.

A)close packed
B)body-centered cubic
C)face-centered cubic
D)amorphous
E)primitive cubic

Question 38

KF crystallizes in a face-centered cubic cell.What is the total number of ions (K⁺ ions and F^- ions)that lie within a unit cell of KF?

A)2
B)8
C)6
D)5
E)4

Question 39

The empirical formula of an addition polymer ________.

A)is the same as that of the monomer from which it is formed except that 2 H and 1 O have been subtracted
B)is the same as that of the monomer from which it is formed except that 1 H and 2 O have been subtracted
C)is the same as that of the monomer from which it is formed except that 2 H and 1 C have been added
D)is the same as that of the monomer from which it is formed
E)is different than that of the monomer from which it is formed

Question 40

All of the following are natural polymers except ________.

A)silk
B)starch
C)nylon
D)protein
E)cellulose

Question 41

The class of ________ has a diamond crystal structure.

A)molecular semiconductors
B)elemental conductors
C)elemental semiconductors
D)nonmetal semiconductors
E)none of the above

Question 42

All of the following are alloys except ________.

A)sterling silver
B)14-karat gold
C)ceramic
D)dental amalgam
E)yellow brass

Question 43

All of the following are polymers except ________.

A)nylon
B)cellulose
C)bronze
D)starch
E)protein

Question 44

What is the percent gold in a 6 karat gold link?

A)94
B)6.0
C)75
D)25
E)1.0 × 10²

Question 45

Which of the following is a condensation polymer?

A)polyvinyl chloride
B)polyethylene
C)polypropylene
D)Nylon 6,6
E)polystyrene

Question 46

What is the percent gold in a 10 karat gold necklace?

A)10
B)58
C)90
D)1.0 × 10²
E)42

Question 47

Which of the following lattices is one of the five two-dimensional lattices in which the lattice vectors a and b are equal and the γ angle between them is 90°?

A)hexagonal
B)rectangular
C)square
D)rhombic
E)oblique

Question 48

Which group of transition metals have the highest melting points?

A)4B
B)6B
C)3B
D)2B
E)8B

Question 49

Which of the following will have a larger band gap: GaN,GaP,GaAs,or GaSb?

A)GaAs
B)GaP
C)GaN
D)GaSb
E)All choices have identical band gaps.

Question 50

Which category of plastics will generally be the most easily recycled?

A)1
B)2
C)3
D)4
E)5

Question 51

Which of the following can be used as an elemental semiconductor?

A)Au
B)H
C)Ge
D)Li
E)Ne

Question 52

Which of the following lattices is one of the seven primitive three-dimensional lattices in which the relationship between the lattice vectors a,b,and c can be written as: a ≠ b ≠ c?

A)rhombohedral
B)hexagonal
C)tetragonal
D)monoclinic
E)cubic

Question 53

Which statement best describes the classification of Sterling silver?

A)It is pure silver.
B)It is oxidized silver.
C)It is an alloy of silver.
D)It is a mixture of silver and gold.
E)It is a liquid at room temperature.

Question 54

When the size of a semiconductor particle or crystal decreases,the band gap energy ________.

A)decreases
B)remains the same
C)increases
D)becomes 1
E)goes to zero

Question 55

Which monomer is polymerized to make natural rubber?

A)urethane
B)ethylene
C)styrene
D)isoprene
E)propylene

Question 56

What is the percent gold in a 14 karat gold ring?

A)86
B)58
C)14
D)42
E)1.0 × 10²

Question 57

What is the percent gold in a 24 karat gold bracelet?

A)100
B)24
C)75
D)25
E)76

Question 58

Which of the following is an addition polymer?

A)polyethylene terephthalate
B)polyurethane
C)Nylon 6,6
D)polyvinyl chloride
E)polycarbonate

Question 59

Blue LEDs are usually made of ________.

A)gallium arsenide
B)gallium phosphide
C)gallium nitride
D)gallium oxide
E)gallium sulfide

Question 60

Which category of plastics is the most difficult to recycle?

A)1
B)2
C)3
D)5
E)7

Question 61

HDPE stands for ________.

Question 62

An unknown metal crystallizes in a body-centered cubic unit cell.There are ________ atoms of the unknown metal per unit cell.

Question 63

What is the correct abbreviation for the polymer low-density polyethylene?

A)P
B)PP
C)PETE
D)LDPE
E)HDPE

Question 64

Many metals are ductile,which means that they can be drawn into thin wires.

Question 65

Define a body-centered cubic lattice.

Question 66

Define a face-centered cubic lattice.

Question 67

Quantum dots can be found as particles in semiconductors.What is the average diameter of quantum dots?

Question 68

What is doping in the semiconductor field?

Question 69

What are semiconductors?

Question 70

What is the chemical formula for the monomer that forms polyethylene?

Question 71

A face-centered cubic unit cell contains contains ________ atoms.

Question 72

When two different monomers combine to form a polymer,the resulting compound is called a ________.

Question 73

What is an alloy?

Question 74

What two compounds react to form the polymer Nylon?

Question 75

The dopant atoms in an ________ semiconductor have more electrons than the host material.

Question 76

What two primary metals are alloyed to produce bronze?

Question 77

Semiconductors are ________ conductive than metals because of a band gap.

Question 78

The type of solid that is characterized by low melting point,softness,and low electrical conduction is a molecular solid.

Question 79

Define a primitive cubic lattice.

Question 80

________ are solid-state materials that can be made either semiconducting or metallic without any doping.