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Flashcards in Exam 1 Deck (92):
1

What are the main postulates of the Bohr model of an atom?

a) The electron travels in circular orbits around the nucleus
b) The orbits have quantized sizes and energies
c) Energy is emitted from the atom when the electron jumps from one orbit to another closer to the nucleus
d) Energy is absorbed by the atom when the electron jumps from one orbit to another further from the nucleus

2

What are the main postulates of wave mechanical model of an atom?

a) Location of an election is defined by probability function
b) Energy quantized in shells and subshells

3

State of an electron can be classified by how many quantum numbers?

4

4

n quantum number is?

Principal quantum number, defines a shell

5

l quantum number is?

Azimuthal quantum number, defines a subshell/orbital

6

m quantum number is?

Magnetic quantum number

7

s quantum number is?

Spin

8

T/F: Paul principle states that two or more electrons cannot occupy the same quantum state.

True

9

What type(s) of electron subshell(s) does L shell contain?

S and P

10

What type(s) of electron subshell(s) does M shell contain?

S, P, and D

11

What is the maximum number of electrons that M shell contains?

18

12

How many (max number) electrons can occupy d-subshell?

10

13

How many (max number) electrons can occupy p-subshell?

6

14

The nucleus of an atom contains?

Protons and neutrons

15

How many atoms in a mole of a substance?

6.022 * 10^23 (Avagadro's number)

16

What is the weight of 1 mole of atoms of Ru?

101.07 g

17

How many electrons does O (oxygen) have?

8

18

Zinc has five naturally occurring isotopes: 48.63% of 64Zn with an atomic weight of 63.929 amu; 27.90% of 66Zn with an atomic weight of 65.926 amu; 4.10% of 67Zn with an atomic weight of 66.927 amu; 18.75% of 68Zn with an atomic weight of 67.925 amu; and 0.62% of 70Zn with an atomic weight of 69.925 amu. Calculate the average atomic weight of Zn.

65.40

19

What is the relationship between four major components involved in materials design, production and utilization?
structure
processing
performance
properties

processing-structure-properties-performance

20

What are the three primary classifications of solids?

a) Polymers
b) Ceramics
c) Metals

21

What are the five examples of advanced materials?

a) "Smart" materials
b) Biomaterials
c) Nanomaterials
d) Composites
e) Semiconductors

22

In general, if material is strong, ductile, possessing high thermal and electrical conductivity, opaque and reflective it most probably is?

Metal

23

Typical polymers are:

a) Low strength
b) Low density
c) Insulators
d) Optically transparent/translucent

24

What are the six major property classifications?

a) Magnetic
b) Deteriorative
c) Optical
d) Thermal
e) Mechanical
f) Electrical

25

By chemical nature typical ceramics are compounds of

Metal and non-metal

26

Considering interaction between two atoms the net force at the equilibrium distance is:

0

27

Considering interaction between two atoms the net energy at the equilibrium distance is:

At its minimum value

28

Considering interaction between two atoms an attractive interaction is typically:

Long range

29

T/F: Primary bonding is created through direct involvement of atoms' electrons

True

30

T/F: In general, secondary bond is stronger (larger bonding energy) than primary bond

False

31

What are the three types of primary bonding?

a) Metallic
b) Ionic
c) Covalent

32

Large difference in electronegativity is required for what kind of bond?

Ionic bonding

33

Which type of bonding has both of the following defining features: small difference in electronegativity and shared electrons:

Covalent

34

The bond energy is lowest for what kind of bond?

Secondary bonding

35

What type of bonding can be expected for KBr?

Ionic

36

What type of bonding can be expected in methane, CH4?

Covalent

37

Considering that typical ceramic materials are compounds of metal and non-metal what type of bonding will be dominating in them?

Ionic

38

What type of bonding is direction?

Covalent

39

Secondary bonding is created by:

Interaction of electric dipoles

40

T/F: Typically solid materials with larger bonding energy are characterized by higher melting point

True

41

What type of bonding would you expect for titanium (Ti)?

Metallic

42

What crystal structure are typical for metals?

a) Hexagonal closed packed
b) Body-centered cubic
c) Face-centered cubic

43

T/F: Atomic packing factor value can be more than 1

False

44

A face atom in cubic structure is shared between how many unit cells?

2

45

What is the coordination number HCP structure?

12

46

Rank the following by increasing APF:
FCC, SC, BCC, HCP

SC, BCC, FCC/HCP

47

A corner atom in cubic structure is shared between how many unit cells?

8

48

How many atoms per unit cell does SC structure have?

1

49

What is the highest APF for metallic structures?

.74

50

A density of amorphous solid material is (assume the crystalline and amorphous materials have the same chemical composition):

Less than the one of crystalline material

51

Which crystal system has the following interaxial angle and lattice parameters relationship?
α = β = γ = 90° , a=b=c

Cubic

52

Which crystal systems has the following interaxial angle relationship?
α = β = γ = 90°

a) Tetragonal
b) Orthorombic
c) Cubic

53

Which crystal systems have the following lattice parameters relationship?
a=b=c

a) Rhombohedral
b) Cubic

54

Find the Miller indices:

x=1 y=0 z=0

(100)

55

Find the Miller indices:

x=0 y=1 z=0

(010)

56

Find the Miller indices:

x=0 y=0 z=1

(001)

57

Find the Miller indices:

x=1 y=1 z=0

(110)

58

Find the Miller indices:

x=1 y=0 z=1

(101)

59

Find the Miller indices:

x=0 y=1 z=1

(011)

60

For cubic crystals, as values of the planar indices h, k, and l increase, how does the distance between adjacent and parallel planes (i.e., the interplanar spacing) change?

Decreases

61

What is the relationship between diffraction angle and critical angle in Bragg's law?

Diffraction angle is equal to two times the critical angle

62

What bond types can ceramics have?

Ionic and covalent

63

What are the main factors influencing crystal structure of ceramics?

a) Relative sizes of ions
b) Magnitude of electrical charge of ions

64

Coordination number 4 means that each (cation/anion) is surrounded by _ anions

a) Cation
b) 4

65

What has an AX-type crystal structure?

a) Zinc Blende
b) Cesium Chloride
c) Rock Salt

66

What has an AX2-type crystal structure?

Fluorite

67

T/F: Only materials incorporating cesium and chlorine may possess Cesium Chloride crystal structure

False

68

Rock Salt has:
_ cations per unit cell
_ anions per unit cell

a) 4
b) 4

69

What arrangement of anions does Rock Salt structure have?

FCC

70

Coordination number in Cesium Chloride structure is

8

71

Zince Blende structure has ___ arrangement of anions and coordination number equal to _

a) FCC
b) 4

72

Perovskite structure has _ anions and _cations per unit cell

a) 3
b) 2

73

What is the type of bonding between carbon atoms in a polymer?

Covalent

74

What is the type of bond between polymer chains in a polymeric materials?

Van der Waals

75

What are two major types of polymerization?

a) Condensation
b) Addition

76

What are three stages of addition polymerization?

a) Termination
b) Initiation
c) Propagation

77

What is the typical relationship between number average and weight average molecular weight in polymeric materials?

Number average < Molecular weight

78

What is a polydispersity index?

Mw/Mn

79

Degree of polymerization is a ration of

Mn to m, m - molecular weight of repeat unit

80

What is the name of the polymer

(CH3 )
(CH Ch2)n

Polypropylene

81

What is the name of the polymer

(H H)
(C C)
(H H)n

Polyethylene

82

What is the name of the polymer

(⬡ H)
(C C)
(H H)n

Polystyrene

83

What is the name of the polymer

(H H)
(C C)
(H Cl)n

Polyvinylchloride

84

What is the name of the polymer

(F F)
(C C)
(F F)n

Polytetrafluoroethylene

85

Polymer _ refers to the arrangement of atom positions along the chain that cannot be altered except by the breaking and reforming of primary bonds

Configuration

86

Define atactic

The repeating units have no regular stereochemical configuration.

87

Define syndiotactic

The repeating units have alternating stereochemical configurations.

88

Define isotactic

All the repeating units have the same stereochemical configuration

89

What are types of copolymers?

a) Random
b) Alternating
c) Block
d) Graft

90

How do the densities of crystalline and amorphous polymers of the same material that have identical molecular weights compare?

Density of crystalline polymer > density of amorphous polymer

91

What is the electron configuration for an inert gas?

1s^2 2s^2 2p^6

92

Which of the following are crystal systems?
Cubic, BCC, FCC, Orthorhombic

a) Cubic
b) Orthorhombic