Test 4

Question 1

Crystalline Solids

Answer 1

ORDERED

Question 2

Amorphous Solids

Answer 2

DISORDERED

Question 3

Crystal Lattices

Answer 3

geometrical patterns of the crystal structures

Question 4

Alloys

Answer 4

combinations of two or more elements that have properties of a metal

Question 5

Substitutional Alloys

Answer 5

A second atom of similar size and reactivity takes the place of a metal atom (Homogeneous)

Question 6

Interstitial Alloys

Answer 6

A second smaller atom, often a nonmetal, fills an empty space in the lattice of metal atoms (Homogeneous)

Question 7

Heterogeneous Alloys

Answer 7

The components of these alloys are not dispersed uniformly throughout the material (not a solid)

Question 8

Intermetallic Compounds

Answer 8

Compounds, NOT mixtures. They are found with specific compositions that cannot be verified (Homogeneous)

Question 9

Ionic Solids

Answer 9

lattice is composed of charged ions

- High BP and MP

Question 10

Metallic Solids

Answer 10

Consist of JUST metals

Question 11

Molecular Solids

Answer 11

Atoms are held together through van der Waals forces

• Often soft and low MP
• Ex: Graphite

Question 12

Covalent-Network Solids

Answer 12

Consists of atoms held together in large networks by covalent bonds - C, Si, Ge

• Hard materials with high MP
• Ex: Diamond

Question 13

Insulators

Answer 13

do not conduct electricity

Question 14

Semiconductors

Answer 14

conductance varies

Question 15

Conductors (Metals)

Answer 15

conduct electricity

Question 16

Band Gap (Eg)

Answer 16

A

Question 17

Conduction Band

Answer 17

forms antibonding orbitals

Question 18

Valence Band

Answer 18

forms bonding orbitals

Question 19

Doping

Answer 19

adding controlled amounts of impurity atoms to a material

Question 20

n-type semiconductor

Answer 20

adding an atom with more valence electrons than the original; adds electrons to conduction band
(Phosphorus-15 to Silicon-14)

Question 21

p-type semiconductor

Answer 21

adding an atom with less valence electrons that the original; less electrons in the valence band
(Aluminum-13 to Silicon-14)

Question 22

Polymers

Answer 22

molecules of high molecular weight

Question 23

Monomers

Answer 23

molecules of low molecular weight

Question 24

Addition Polymers

Answer 24

Couple monomers by converting pi-bonds to sigma-bonds between monomers

Question 25

Condensation Polymers

Answer 25

Joining two different monomers in which a smaller molecule is formed as a by-product

Question 26

Crystallinity

Answer 26

the order of polymers | Increased Order = Higher MP, Density

Question 27

Cross-Linking

Answer 27

chemically bonding chains of polymers to stiffen and strengthen substance

Question 28

Vulcanization

Answer 28

discovered in 1839 by Charles Goodyear, chains are cross-linked and make rubber bonds stronger

Question 29

Nanotechnology

Answer 29

the creation of devices with dimensions of 1-100 nm | 10^-9 m

Question 30

Quantum Dots

Answer 30

very small semiconductor particles (1-10 nm)

Question 31

Particle Size Decreases

Answer 31

Band Gap increases

Question 32

Carbon Nanotube

Answer 32

similar to a graphite layer that has been rolled up

Question 33

Oxidation-Reduction Reactions

Answer 33

chemical reactions that move electrons around

Question 34

oxidation

Answer 34

LOSES electrons (becomes more positive)

Question 35

reduction

Answer 35

GAINS electrons (becomes more negative)

Question 36

Oxidation Number

Answer 36

the actual charge of the atom if it exists as a monatomic ion

Question 37

Steps to Balancing Redox Equations

Answer 37

1. Assign oxidation numbers. 2. Divide into two half-reactions. 3. Balance each half equation. - Elements other than O and H. - Add H20 to balance oxygen. - Add H+ to balance hydrogen. - Add electrons to balance charge. 4. Multiply each half-reaction so the number of electrons is equal on both sides. 5. Check to see masses and charges are equal.

Question 38

Voltaic Cells

Answer 38

a setup that uses energy released through oxidation-reduction reactions to do work by making electrons flow through an external device

Question 39

Anode

Answer 39

Oxidation

Question 40

Cathode

Answer 40

Reduction

Question 41

Liquid Crystals

Answer 41

the viscous state of some substances between liquid and solid states

Question 42

Liquids

Answer 42

No structure

Question 43

Nematic

Answer 43

ordered in one dimension I I I I I I I II I I I II I I

Question 44

Smectic

Answer 44

ordered in two dimensions IIIIIII ////// IIIIIII or ////// IIIIIII //////

Question 45

Cholesteric

Answer 45

layered at angles

Question 46

Liquid Crystal Displays

Answer 46

The layer of liquid crystal between two conductive glass windows in which light is polarized