Deck 12: Solids and Modern Materials

Question 1

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

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

Answer 1

diffraction

Question 2

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

Answer 2

primitive cubic

Question 3

Which property of metals cannot be explained with the electron-sea model?

A)shine
B)high thermal conductivity
C)high electric conductivity
D)malleability and ductility
E)trends in melting points

Answer 3

trends in melting points

Question 4

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 5

Heterogeneous alloys

A)have properties that depend on composition.
B)have properties that depend on the manner in which the melt is solidified.
C)have properties that depend on the manner in which the solid is formed.
D)All of the above are true.

Question 6

An alloy is a

A)heterogeneous mixture of two metals.
B)pure metal.
C)metallic material that is composed of two or more elements.
D)nonmetal with some properties of a metal.
E)mineral containing two or more metals.

Question 7

Which of the following is not a type of solid?

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

Question 8

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 9

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 10

Which element is typically not added to steel to modify its properties?

A)carbon
B)vanadium
C)chromium
D)nitrogen
E)nickel

Question 11

Metallic solids do not exhibit ________.

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

Question 12

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

Question 13

Consider the following statements about crystalline solids: (i)Molecules or atoms in molecular solids are held together via
Intermolecular forces.
(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)Atoms in covalent-network solids are connected via a network
Of covalent bonds.
Which of the statements is false?

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

Question 14

Intermetallic compounds are examples of

A)homogeneous alloys.
B)heterogeneous alloys.
C)interstitial alloys.
D)solution alloys.
E)ionic compounds.

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

Which one of the following cannot form a solid with a lattice based on the sodium chloride structure?

A)NaBr
B)LiF
C)RbI
D)CuO
E)CuCl₂

Question 17

What is the typical effect of the addition of an interstitial element on the properties of a metal?

A)increase in malleability and corrosion resistance
B)increase in hardness and strength, decrease in ductility
C)decrease in melting point and increase in ductility
D)decrease in conductivity and increase in brittleness
E)increased surface luster

Question 18

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

Question 19

Alloys generally differ from compounds in that

A)the former always contain some carbon.
B)the former always contain some iron.
C)the former always have semiconductor properties.
D)the atomic ratios of the constituent elements in the former are not fixed and may vary over a wide range.
E)the former never contain a transition element.

Question 20

Which statement about steel is false?

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

Question 21

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

Question 22

As a polymer becomes more crystalline, ________.

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

Question 23

The molecular-orbital model for Ge shows it to be

A)a conductor, because all the lower energy band orbitals are filled and the gap between the lower and higher bands is large.
B)an insulator, because all the lower energy band orbitals are filled and the gap between the lower and higher bands is large.
C)a semiconductor, because the gap between the filled lower and empty higher energy bands is relatively small.
D)a semiconductor, because the gap between the filled lower and empty higher energy bands is large.
E)a conductor, because its lower energy band orbitals are only partially filled.

Question 24

The formation of a condensation polymer generally involves ________.

A)the addition of a plasticizer
B)the mixing of sulfur with an addition polymer
C)the elimination of a small molecule
D)the vaporization of a plasticizer
E)the formation of significant crosslinking

Question 25

Gallium crystallizes in a primitive cubic unit cell. The length of the unit cell edge is 3.70 Å. The radius of a Ga atom is ________ Å.

A)7.40
B)3.70
C)1.85
D)0.930
E)Insufficient data is given.

Question 26

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 and 8
B)2 and 1
C)1 and 1
D)2 and 2
E)2 and 4

Question 27

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 chloride
B)polypropylene
C)polystyrene
D)polyurethane
E)nylon 6, 6

Question 28

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 29

Which of the following is not a natural polymer?

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

Question 30

Inorganic compounds that are semiconductors have an average of ________ valence electrons.

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

Question 31

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 32

Potassium metal crystallizes in a body-centered cubic structure with a unit cell edge length of 5.31 Å. The radius of a potassium atom is ________ Å.

A)1.33
B)1.88
C)2.30
D)2.66
E)5.31

Question 33

The properties of graphene include ________.

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

Question 34

________ solids consist of atoms or molecules held together by dipole-dipole forces, London dispersion forces, and/or hydrogen bonds.

A)Ionic
B)Molecular
C)Metallic
D)Covalent-network
E)Metallic and covalent-network

Question 35

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 36

Which of the following is not classified as a nanomaterial?

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

Question 37

Natural rubber is too soft and chemically reactive for practical applications. Vulcanization of natural rubber entails ________.

A)conversion of an addition polymer to a condensation polymer
B)conversion of a condensation polymer to an addition polymer
C)increasing the average molecular weight of a condensation polymer
D)decreasing the average molecular weight of an addition polymer
E)crosslinking reactive polymer chains with sulfur atoms

Question 38

The process of doping can produce a(n)________, which can greatly ________ intrinsic conductivity.

A)n-type semiconductor, increase
B)p-type semiconductor, decrease
C)non-metal, increase
D)non-metal, decrease
E)allotrope, diminish

Question 39

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 40

An ionic solid, NaCl (s), dissolves in water because of the ________.

A)relatively low lattice energy due to small charges of Na⁺ and Cl^- ions
B)simple face-centered cubic unit cell type it forms
C)1:1 ratio of ions in the unit cell
D)strong coulombic interactions between oppositely charged ions
E)relatively low melting point

Question 41

The transition metals in group ________ have the highest melting points.

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

Question 42

Of the following, only ________ is not a polymer.

A)dental amalgam
B)cellulose
C)Teflon
D)plastic
E)protein

Question 43

The class of semiconductors, known as elemental, has special features. These are ________.

A)band gap and individual element valence electrons
B)periodical table grouping and diamond crystal structure
C)tetrahedral coordination geometry and sp² hybrid orbitals
D)overlapping hybrid orbitals and filed conduction bands
E)none of the above

Question 44

18 karat gold contains ________% gold.

A)18
B)25
C)89
D)75
E)1.0 × 10²

Question 45

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

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

Question 46

A category ________ plastic container will generally be the most easily recycled.

A)1
B)2
C)3
D)4
E)22

Question 47

Blue LEDs are usually made of ________.

A)GaAs
B)GaP
C)GaO
D)GaS
E)GaN

Question 48

Sterling silver is ________.

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

Question 49

The ________ lattice 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)square
B)rectangular
C)hexagonal
D)rhombic
E)oblique

Question 50

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

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

Question 51

6.0 karat gold contains ________% gold.

A)6.0
B)25
C)50.
D)75
E)1.0 × 10²

Question 52

The ________ lattice 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)monoclinic
B)hexagonal
C)rhombohedral
D)tetragonal
E)cubic

Question 53

Of the following, only ________ is a condensation polymer.

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

Question 54

Of the following, only ________ is an addition polymer.

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

Question 55

Which of the following is not an alloy?

A)elemental gold
B)sterling silver
C)18-karat gold
D)dental amalgam
E)bronze

Question 56

Which of the following could be useful as an elemental semiconductor?

A)As
B)Zn
C)I
D)K
E)He

Question 57

12 karat gold contains ________% gold.

A)12
B)25
C)50.
D)75
E)1.0 × 10²

Question 58

A sample of natural rubber (200.0 g)is vulcanized, with the complete consumption of 4.8 g of sulfur. Natural rubber is a polymer of isoprene (C₅H₈). Four sulfur atoms are used in each crosslink connection. What percent of the isoprene units will be crosslinked?

A)7.6
B)5.1
C)2.5
D)9.4
E)1.3

Question 59

24 karat gold contains ________% gold.

A)24
B)25
C)50.
D)75
E)1.0 × 10²

Question 60

The monomer that is polymerized to make natural rubber is ________.

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

Question 61

Nylon is formed by the reaction of a(n)________ with a(n)________.

Question 62

When lattice points occur only at the corners of a unit cell, the cell is called ________.

Question 63

The correct abbreviation for the polymer low-density polyethylene is ________.

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

Question 64

The dopant atoms in an n-type semiconductor have ________ electrons than the host material.

Question 65

When lattice points occur at the center of each face, as well as each corner of a unit cell, the cell is called ________.

Question 66

Semiconductor particles with diameters of 1-10 nm are called ________.

Question 67

In addition to differences in their average molecular mass, HDPE and LDPE differ in their degree of ________ and their ________ of the chains.

Question 68

Chromium crystallizes in a body-centered cubic unit cell. There are ________ chromium atoms per unit cell.

Question 69

Semiconductors are less conductive than metals because of ________ gap.

Question 70

Write the chemical formulas for both polyethylene and the monomer from which it is formed.

Question 71

How many atoms are contained in a face-centered cubic unit cell?

Question 72

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

Question 73

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

Question 74

When lattice points occur at the corners and at the center of a unit cell, the cell is called ________.

Question 75

________ are materials characterized by an energy gap between a filled valence band and an empty conduction band.

Question 76

The process of adding controlled amounts of impurity atoms to a material is known as ________.

Question 77

Many metals are ductile, which means that they can be hammered into thin sheets.

Question 78

What two metals are alloyed to produce sterling silver?

Question 79

Polymers formed from two different monomers are called ________.

Question 80

A material that contains more than one element and has the characteristic properties of metals is called a(n)________.