Central Science: Chapter 12 Flashcards


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1

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

D

2

All of the following are a type of solid except ________.
A) supercritical
B) ionic
C) molecular
D) covalent network
E) metallic

A

3

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

B

4

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

C

5

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

B

6

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

B

7

The ________ of light waves upon passing through a narrow slit is called diffraction.
A) diffusion
B) scattering
C) grating
D) adhesion
E) incidence

B

8

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

D

9

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

A

10

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

D

11

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

D

12

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

C

13

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

D

14

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.

C

15

________ 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

B

16

________ are examples of homogeneous alloys.
A) Covalent compounds
B) Interstitial compounds
C) Intermetallic compounds
D) Intrametallic compounds
E) Ionic compounds.

C

17

________ 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

B

18

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

B

19

Metallic solids exhibit all of the following except ________.
A) thermal conductivity
B) brittleness
C) electrical conductivity
D) variable melting point
E) variable hardness

B

20

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

B

21

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

B

22

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

B

23

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

C

24

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

B

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

C

26

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

C

27

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

A

28

How many valence electrons do inorganic compounds contain if they are considered semiconductors?
A) 2
B) 1
C) 4
D) 5
E) 3

C

29

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

B

30

All of the following are natural polymers except ________.
A) silk
B) starch
C) nylon
D) protein
E) cellulose

C

31

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

D

32

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

E

33

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.

E

34

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

E

35

The formation of a ________ polymer generally involves the elimination of a small molecule.
A) conversion
B) vulcanization
C) monomeric
D) condensation
E) polymerization

D

36

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

C

37

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

E

38

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

E

39

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.

B

40

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

A

41

What is the percent gold in a 14 karat gold ring?
A) 86
B) 58
C) 14
D) 42
E) 1.0 × 102

B

42

What is the percent gold in a 10 karat gold necklace?
A) 10
B) 58
C) 90
D) 1.0 × 102
E) 42

E

43

What is the percent gold in a 24 karat gold bracelet?
A) 100
B) 24
C) 75
D) 25
E) 76

A

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

D

45

Which group of transition metals have the highest melting points?
A) 4B
B) 6B
C) 3B
D) 2B
E) 8B

B

46

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

C

47

Blue LEDs are usually made of ________.
A) gallium arsenide
B) gallium phosphide
C) gallium nitride
D) gallium oxide
E) gallium sulfide

C

48

Which category of plastics is the most difficult to recycle?
A) 1
B) 2
C) 3
D) 5
E) 7

E

49

Which category of plastics will generally be the most easily recycled?
A) 1
B) 2
C) 3
D) 4
E) 5

A

50

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

C

51

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

C

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

D

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.

C

54

All of the following are alloys except ________.
A) sterling silver
B) 14-karat gold
C) ceramic
D) dental amalgam
E) yellow brass

C

55

Which of the following can be used as an elemental semiconductor?
A) Au
B) H
C) Ge
D) Li
E) Ne

C

56

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.

C

57

All of the following are polymers except ________.
A) nylon
B) cellulose
C) bronze
D) starch
E) protein

C

58

Which monomer is polymerized to make natural rubber?
A) urethane
B) ethylene
C) styrene
D) isoprene
E) propylene

D

59

Which of the following is an addition polymer?
A) polyethylene terephthalate
B) polyurethane
C) Nylon 6,6
D) polyvinyl chloride
E) polycarbonate

D

60

Which of the following is a condensation polymer?
A) polyvinyl chloride
B) polyethylene
C) polypropylene
D) Nylon 6,6
E) polystyrene

D

61

What is the correct abbreviation for the polymer low-density polyethylene?
A) P
B) PP
C) PETE
D) LDPE
E) HDPE

D

62

Define a primitive cubic lattice.

when lattice points occur only at the corners of a unit cell

63

Define a body-centered cubic lattice.

when lattice points occur at the corners and at the center of a unit cell

64

Define a face-centered cubic lattice.

when lattice points occur at the center of each face, as well as each corner of a unit cell

65

What is an alloy?

a material that contains more than one element and has the characteristic properties of metals

66

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

4

67

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

2

68

What two primary metals are alloyed to produce bronze?

copper and tin

69

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

less

70

What are semiconductors?

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

71

What is doping in the semiconductor field?

the process of adding controlled amounts of impurity atoms to a material

72

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

n-type

73

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

1-10 nm

74

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

H2C=CH2

75

What two compounds react to form the polymer Nylon?

hexamethylen diamine and adipic acid

76

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

copolymer

77

HDPE stands for ________.

high-density polyethylene

78

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

Carbon nanotubes

79

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

true

80

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

true

81

An insulator does not conduct electricity.

true

82

Polyethylene is formed by a condensation reaction.

false

83

Vulcanization of natural rubber entails crosslinking reactive polymer chains with sulfur atoms.

true

84

Thermoplastics cannot be reshaped.

false