Quiz Study 1-8

Question 1

On the basis of ionic charge and ionic radii, predict the crystal structure of CsI

Answer 1

Find the cation-anion ratio to find the coordination number.

Question 2

Describe why most ceramic materials are brittle and show no plastic deformation.

Answer 2

In ceramics there is resistance to sliding and sliding is plastic deformation. Therefore, no plastic deformation.

Question 3

Describe the difference in specific volume change with temperature between amorphous glasses and crystalline ceramics

Answer 3

Crystalline ceramics has an abrupt change in specific volume when T changes. Amorphous has a gradual change in viscosity.

Question 4

Describe the benefit of adding soda and lime in terms of glass forming

Answer 4

Working range is improved and can work on glass @ lower T.

Question 5

Describe the process and strengthening mechanism of tempered glass

Answer 5

Heat above transition T & below softening point followed by a controlled cool down. Compression is applied to suppress cracks.

Question 6

Briefly describe the difference in the function of water in hydroplasticity and cementation.

Answer 6

Water molecules fit in between layered sheets and reduces degree of Van der Waals allowing for particles to move past one another. Cementation, water performs chemical bonding by hydration and not drying.

Question 7

Describe the process of polymerization.

Answer 7

A chain of polymers is made. A reaction between a monomer & a free radical. This propagates by adding new monomers.

Question 8

Describe the states and property of polymer vs molecular weight relationship.

Answer 8

A high molecular weight increases stretchability, impact resistance, chemical resistance, & viscosity.

Question 9

Describe how the molecular chain of polymers can be bent, coiled, and kinked in terms of
bonding of backbone carbon atoms (C-C).

Answer 9

As long as the angle between the previous C atom. In tetrahedral shape and not in a straight chain and the atoms are relatively free to rotate around a single C-C bond.

Question 10

Describe four molecular structures of polymers

Answer 10

Linear (Spaghetti), Branched (similar to linear w/ branches), cross linked (additives), Network (Reinforced Cross link)

Question 11

Describe isotactic configuration, syndiotactic configuration, atactic configuration of polymers.

Answer 11

Isotactic-R groups are in same side of chain,
Syndiotactic- R groups alternate on side of chains
Atactic- R groups are random

Question 12

When comparing crystalline polymers and amorphous polymers, which one has higher
density?

Answer 12

Amorphous are less packed than crystalline.

Question 13

Describe three typical stress-strain curves of polymers and their microstructural changes during deformation

Answer 13

Brittle- Some gradual elastic deformation followed by a sudden fracture.
Plastic- Elastic deformation followed by plastic deformation.
Elastometer- Large elastic strain @ low stress

Question 14

Describe the difference between thermoplastic and thermoset polymers.

Answer 14

Thermoplastic- soften when heated & hardened when cold can be repeated.
Thermosetting- Will become permanently deformed and does not soften when heated.

Question 15

Describe two types of polymerization processes.

Answer 15

Addition- When you add monomer units to form a macro-molecule
Condensation- Inter-molecular chemical reactions that may involve more than one monomer species.

Question 16

Describe the difference between fillers and plasticizers in terms of their functions to the mechanical properties in the polymers.

Answer 16

fillers- added to improve flexibility, ductility, toughness, stiffness.
Plasticizers- transforms from brittle to ductile.

Question 17

Describe matrix and dispersed phases in composite materials.

Answer 17

matrix- transferred stress to dispersed phases and protects from environment.
Dispersed- Discontinuous with different sized particles, wires, & meshes.

Question 18

Describe the critical length of fibers in fiber-reinforced composites.

Answer 18

Minimal length so that the entire load is transferred from matrix to fiber

Question 19

Describe the mechanical properties (stress-strain curve and elastic modulus) of
continuous and aligned fiber composites in longitudinal loading conditions.

Answer 19

fibers stretch elastically and tensile strength of fiber is higher than the yield strength of the matrix.

Question 20

Describe three different common types of polymer-matrix composites.

Answer 20

glass fiber, carbon fiber, and aramid fiber

Question 21

Describe two typical types of structural composites.

Answer 21

Sandwich panel and Laminate Composite.

Question 22

Ceramic materials are mostly compounds consisting of metallic and nonmetallic
elements

Answer 22

True

Question 23

Ceramic materials have high hardness and high toughness

Answer 23

False

Question 24

Hydration is a process used in the forming of ceramic clays

Answer 24

False

Question 25

Soda-lime classes are easier to fabricate than pure silica (fused silica).

Answer 25

True

Question 26

The density of crystalline polymers is the same as that of amorphous polymers

Answer 26

False

Question 27

A chemical reaction between two or more monomer species, producing byproducts such
as water, occurs in condensation polymerization.

Answer 27

True