Mat Sci Test 1

Front 1

Ceramics are typically very hard - true or false?

Back 1

True

Front 2

_________ are typically organic materials - ceramics or polymers?

Back 2

polymers

Front 3

The study of materials is called:

Back 3

metallurgy

Front 4

The name _________ comes from the Greek word for “burn earth”

Back 4

ceramics

Front 5

A combination of two or more metals or a metal and a nonmetal is __________

Back 5

polymer

Front 6

_______ Number is the number of protons in the nucleus of an atom

Back 6

atomic number

Front 7

Anion is a __________ charged ion produced when an atom, usually of a non-metal, accepts one or more electrons

Back 7

anion is negatively charged

Front 8

Atomic number is the number of ________ in an atom

Back 8

protons

Front 9

Pauli’s exclusion principle states that no two electrons have have the same set of four quantum numbers - true or false?

Back 9

true

Front 10

_______ quantum number is a quantum number representing the energy level of the electron

Back 10

principal

Front 11

Isotopes are atoms of the same element that have the same number of ________ but not the same number of neutrons

Back 11

protons

Front 12

Steels contain ________ than 2% of carbon - more or less

Back 12

less

Front 13

Avogadro’s number corresponds to the number of ______ needed to create a mass in units of grams numerically equal to the atomic mass in amu of the substance under consideration

Back 13

atoms

Front 14

One atom of oxygen has a mass of 16 amu; what is the mass in grams of one mole of oxygen atoms

Back 14

16 g

Front 15

Outer electrons (high energy electrons) are the valence electrons - true or false?

Back 15

true

Front 16

Vand der Waals are _______ bonds - primary, secondary, tertiary?

Back 16

secondary

Front 17

The mechanical properties of metals are significantly different that those of ionic and covalent networked materials - true or false?

Back 17

true

Front 18

Transition metals have what kind of bonding?

Back 18

mixed metallic covalent

Front 19

ionic solids generally have ______ melting temperatures - low or high?

Back 19

high

Front 20

Which is not a primary bond? A) covalent b) hydrogen c) ionic d) metallic

Back 20

b) hydrogen!

Front 21

When atoms release electrons they have a positive charge and are called _____

Back 21

cations

Front 22

1 amu/atom = 1 g/mol - true or false?

Back 22

false

Front 23

covalent bonds are very weak - true or false

Back 23

false

Front 24

Sodium chloride is the classic covalent material

Back 24

true

Front 25

_________ is the fraction of the volume of a unit cell that is occupied by a “hard sphere” atoms or ions

Back 25

atomic packing factor (APF)

Front 26

The atomic packing factor for FCC is ______

Back 26

0.74

Front 27

For the BCC crystal structure, each corner atom is shared among _______ unit cells

Back 27

8 unit cells

Front 28

the atomic packing factor for BCC is ____

Back 28

0.68

Front 29

For the FCC crystal structure, each corner atom is shared among _____ unit cells

Back 29

8 unit cells

Front 30

The equivalent of ______ atoms is contained in each HCP unit cell

Back 30

6 atoms

Front 31

APF is the volume of the unit cell divided by the volume of atoms in each selected unit cell - true or false?

Back 31

false

Front 32

Materials that have more than one crystal structure are called ______

Back 32

allotropic

Front 33

The _______ is the number of atoms touching a particular atom, or the number of nearest neighbors for that particular atom

Back 33

coordination number

Front 34

__________ are long, thin grains in solidified polycrystalline structure

Back 34

columnar grains

Front 35

Iron exists in _____
(number) crystal structure over the temperature range from room temperature to its melting point

Back 35

2 crystal structures

Front 36

_____ Law gives the relationship among the angular positions of the reinforced diffracted beams in terms of the wavelength of the incoming X-ray radiation and of the interplanar spacing of the crystal planes

Back 36

Bragg's Law

Front 37

_______ Nucleation is a liquid melt occurs when the metal itself provides the atoms needed to form a nuclei

Back 37

homogeneous

Front 38

______ nucleation is nucleation that occurs in a liquid on the surfaces of its container, insoluble, impurities, and other structural material that lower the critical free energy required to form a stable nucleus

Back 38

heterogeneous

Front 39

Continuous casting has been fabricated in _______

Back 39

cast houses

Front 40

Nuclei is small particles of a new phase formed by a phase change that can grow until the phase change is complete - true or false

Back 40

true

Front 41

______ is a single crystal in a polycrystalline aggregate

Back 41

grain

Front 42

columnar grains are long, thin grains in a solidified polycrystalline structure - true or false?

Back 42

true

Front 43

To produce cast ingots with a fine grain size, grain refiners are usually added to the liquid metal before castings - true or false

Back 43

true

Front 44

There are ____ main types of dislocations (number)

Back 44

2

Front 45

Dislocations are ______ imperfections

Back 45

line imperfections

Front 46

_____ is a single crystal in a polycrystalline aggregate

Back 46

grain

Front 47

grain boundaries are _____

Back 47

surface imperfections

Front 48

the displacement distance of the atoms around the dislocation is called _____

Back 48

burgers! Yum!

Front 49

_____ is a point imperfection in a crystal lattice where an atom is missing from an atomic site

Back 49

vacancy

Front 50

______ solid solution is a solid solution in which solute atoms of one element can replace those of solvent atoms of another element

Back 50

substitutional

Front 51

_____ grains are long, thin grains in solidified polycrystalline structure

Back 51

columnar grains

Front 52

crystal lattice imperfections are classified according to their geometry and shape - true or false?

Back 52

true

Front 53

There are ____ types of solid solutions (number)

Back 53

2

Front 54

What are the five main classes of engineering materials?

Back 54

metals, ceramics, polymers, composites, and electronics

Front 55

Properties of metals

Back 55

strong, hard; can be strengthened through alloying, mechanical and heat treatment; ductile

Front 56

properties of polymers

Back 56

plastics; noncrystalline organic molecules; poor conductors, used as insulators; wide range of strength and ductility

Front 57

properties of ceramics

Back 57

high resistance to hear, brittle; strong in compression; involve chemical bonding of metallic and nonmetallic elements; good insulators

Front 58

properties of composites

Back 58

combine favorable properties of multiple classes of materials; two types: fiborous and particulare

Front 59

properties of electronics

Back 59

not a large volume; silicon is very important

Front 60

Describe smart materials

Back 60

smart materials can sense external stimuli and respond by changing mechanical or electrical properties, or appearance

Front 61

simple diffusion is defined as the movement of _____

Back 61

molecules from areas of higher concentraion to areas of lower concentraion

Front 62

when sugar is mixed with water, equilibrium is reached when

Back 62

the dissolved sugar molecules are evenly distributed throughout the solution

Front 63

the rate of diffusion is affected by:

Back 63

temperature, size of molecules, steepness of concentration gradient

Front 64

the molecules in a solid lump of sugar do not move - true or false

Back 64

false

Front 65

diffusion is one of the processes whereby materials are exchanged between a cell and its environment - true or false?

Back 65

true

Front 66

What are the names of the 4 quantum numbers?

Back 66

Principal quantum number, orbital, magnetic, spin

Front 67

What is the structure of something with 18 electrons

Back 67

1s^2 2s^2 2p^6 3s^2 3p^6