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MSE
Materials Science
48
Chemistry
Undergraduate 2
04/30/2012

Additional Chemistry Flashcards

 


 

Cards

Term
T/F Metallic materials have directional primary atomic bonding between atoms
Definition
F
Term
T/F In ceramics, the degree of ionic bonding is inversly related to the electronegativity difference between the elements
Definition
F
Term
T/F Covalent bonds are directional in nature
Definition
T
Term
T/F Weak atomic bonds are characterized by low thermal expansion coefficients
Definition
F
Term
T/F The atomic packing factor for BCC structures is higher than for FCC structures
Definition
F
Term
T/F The stacking sequence of close packed planes of atoms determines whether a structure is FCC or HCP
Definition
T
Term
T/F Elastomers stretch when a stress is applied and recover their original shape when stress is removed
Definition
T
Term
T/F Thermosetting polymers can reversibly soften and flow when heated or treated with appropriate solvents
Definition
F
Term
T/F Grain boundaries are a type of point defect in crystalline materials
Definition
F
Term
T/F Intrinsic semiconductors depend on small amounts of dopants for their semiconducting properties
Definition
F
Term
Name the two factors that control how ions are packed in ceramic structures
Definition
1-ratio of ion radii
2-charge neutrality
Term
Name the two types of solid solutions
Definition
1-interstitial replacement
2-substitutional
Term
with the exception of helium, how manuy electrons are in the outer-most shell of the Noble Gases from column VII of the periodic table
Definition
8
Term
what is the name of the outer most shell electrons
Definition
valence
Term
The element calcium (Ca) is located in row (period) 4 and column II of the periodic table. Write the electron for the outermost shell of calcium using spdf notation
Definition
4s^2
Term
the element oxygen is located in row 2 and column V! of the periodic table. Write the electron for the outermost shell of calcium using spdf notation
Definition
2s^2 2p^4
Term
in ionic compounds, does the coordination number increase or decrease as the cation to anion radius ratio increase
Definition
increase
Term
Metal or nonmetal? 4 or more valence electrons
Definition
nonmetal
Term
Metal or nonmetal? low electronegativity
Definition
metal
Term
Metal or nonmetal? forms cations
Definition
metal
Term
list four considerations required for extensive substitutional solid solution solubility in metal alloys (Hume Rothery Rules)
Definition
1-difference in atomic radii<15%
2-same crystal structure
3-same valence electrons
4-low difference in electronegativity
Term
T/F the electrical conductivity of an intrinsic semiconductor decreases with an increasing temperature
Definition
False
Term
T/F adding Boron atoms from column II in the periodic table to Silicon from Column IV produces a p-type extrinsic semiconductor
Definition
False
Term
T/F electrical resistance is a materials property
Definition
True
Term
T/F increasing the yield strength of a metal by cold working will increase the ductility of the material
Definition
False
Term
T/F the ultimate strength of ceramics is the same in compression and as in tension
Definition
False: compression>tension
Term
T/F Polymeric materials are brittle at temperatures below the glass transition temperature
Definition
True
Term
T/F As the degree of polymerization is increased, the strength of the polymer decreases
Definition
False
Term
T/F when a cold worked metal is annealed, new, strain-free grains are nucleated during the grain growth phase of annealing
Definition
False
Term
T/F The mechanical properties of a uniaxial fiber reinforced composite are anisotropic
Definition
True
Term
if the volume fractions of fiber and matrix are equal, which of these conditions will produce a stronger composite, isostrain or isostress?
Definition
isostrain
Term
T/F Austenite is a FCC solid solution of carbon in iron
Definition
True
Term
T/F The hardness of martensite is a function of ots carbon content
Definition
True
Term
T/F Ferrite (alpha) is a FCC solid solution of carbon in Iron
Definition
False
Term
T/F An eutectic reaction is an example of an invariant reaction
Definition
True
Term
T/F An eutectoid reaction is an example of a solid-state invariant reaction
Definition
True
Term
T/F Interstitial diffusion is slower than vacancy diffusion
Definition
False
Term
T/F Fick's first law of diffusion applies only to steady-state diffusion
Definition
True
Term
T/F Diffusivity of one element in another is a function of temperature
Definition
True
Term
T/F Solidification of cast iron in a sand mold is initiated by homogeneous nucleation
Definition
False
Term
T/F An isomorphous phase diagram results when two elements are completely miscible in each other
Definition
True
Term
Three steps during the precipitation hardening of alloys in sequence.
Definition
1-Soluutionize
2-Quench
3-Aging
Term
T/F The toughness of BCC metals increases as the temperature decreases
Definition
False
Term
An interstitial solid solution of carbon in BCC iron.
austenite b) ferrite c) pearlite d) cementite e) martensite
Definition
B
Term
A two phase microstructure which is the result of the eutectoid decomposition of the γ-phase.
austenite b) ferrite c) pearlite d) cementite e) martensite
Definition
C
Term
An interstitial solid solution of carbon in FCC iron.
austenite b) ferrite c) pearlite d) cementite e) martensite
Definition
A
Term
A metastable phase produced by fast cooling from the γ-phase.
austenite b) ferrite c) pearlite d) cementite e) martensite
Definition
E
Term
A stoichiometric compound Fe3C; a hard and brittle phase.
austenite b) ferrite c) pearlite d) cementite e) martensite
Definition
D
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