CHE 205 Study Guide - Midterm Guide: Atomic Packing Factor, Lattice Constant, Dispersity
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For each of the following material properties, mark whether metals or ceramics would typically have a higher value (mark both if its not clear).
Ceramics Metals
Maximum Tensile Strength (Ideal) _______ ______
Maximum Tensile Strength (in practice) _______ ______
Elastic Modulus _______ ______
Ductility _______ ______
Thermal Conductivity _______ ______
Corrosion Resistance _______ ______
Impact Toughness _______ ______
Scratch Resistance _______ ______
Ease of Manufacture _______ ______
Cost _______ ______
Prove the minimum ratio of the ionic radii in an octahedral pair (coordination # = 6) is 0.414. (Hint: Draw a picture of what a coordination number = 6 would look like)
Describe the difference in the atomic behaviors (specifically viscosity) of crystalline and amorphous ceramics as they heat up.
Determine the coordination number for the following pairs:
MgO
Al2S3
BaO
NiS
Which of the following is not an advantage of powder sintering
Faster processing
Ease of final shape processing
High Strength
Lower temperature/energy requirements
Assume you make a semi-conductor out of germanium, and dope it with nitrogen. What type of semi-conductor is the result?
N-Type -or- P-Type
Match the form of carbon to its description
Graphite | sp2 bonding, but folded on itself to get strength and 3-D stability together. Expensive to make, but promising properties. |
Diamond | Single plane of extremely strong bonds, excellent conductivity. |
Graphene | Planar structure of sp2 bonding, stacked in layers. Extremely strong in plane, weak between layers. Used as a lubricant. |
Fullerenes/nanotubes | 3-D crystalline structure of sp3 bonds. Extremely stable, so very hard |