Chp 4

Front 1

Heat (Q) is the amount of ________ that is transferred from an area at high temperature to an area at low temperature.

Back 1

energy

Front 2

When the temperature of a material is increased, the _________ of the lattice vibrations increases.

Back 2

amplitude

Front 3

For a mole of material, the increment of heat (dQ) added to the material divided by the change in temperature (dT) is the heat _______.

Back 3

capacity

Front 4

The heat capacity is also known as the ______ specific heat.

Back 4

molar

Front 5

Specific heat (c) is the heat capacity per unit ______.

Back 5

mass

Front 6

The primary reason for the high specific heat of polymers is their low monomer _____.

Back 6

mass

Front 7

In semi-crystalline polymers, there is a spike in the specific heat when the crystallites start to _____.

Back 7

melt

Front 8

The sum of the kinetic and potential energy is equal to the _______ energy.

Back 8

internal

Front 9

For a material that has no applied fields, the major contribution to the potential energy is the energy of chemical _______.

Back 9

bonding

Front 10

The _______ is the internal energy plus the pressure times the volume.

Back 10

enthalpy

Front 11

Internal energy is a ______ variable.

Back 11

state

Front 12

In a solid, the average kinetic energy is equal to the average ________ energy.

Back 12

potential

Front 13

The high-temperature heat capacity at constant volume for a solid or liquid is equal to __.

Back 13

3R

Front 14

The change in length of a material per degree divided by the original length is the linear coefficient of thermal ________.

Back 14

expansion

Front 15

A(n) ________ material has the same properties in all directions.

Back 15

isotropic

Front 16

For a polymer filament, the linear coefficient of thermal expansion would be expected to be ____ in the axial direction than in the transverse direction.

Back 16

less

Front 17

A material with an interatomic potential perfectly symmetric about the equilibrium interatomic separation would have a coefficient of thermal expansion equal to ____.

Back 17

zero

Front 18

Copper melts at 1085°C and ________ melts at 1769°C. Which material should have the smaller coefficient of thermal expansion?

Back 18

platinum

Front 19

In heat transfer, the heat flux is directly related to the temperature ___________.

Back 19

gradient

Front 20

Diamond has a notably high thermal conductivity because of its strong ______________.

Back 20

chemical bonding

Front 21

What has the higher thermal conductivity, metallic aluminum or aluminum oxide?

Back 21

aluminum

Front 22

Which should have the higher thermal conductivity, a single-crystal gas-turbine blade or a polycrystal turbine blade?

Back 22

single-crystal gas-turbine blade

Front 23

HDPE is more crystalline than LDPE; of these two _____ should have a lower thermal conductivity.

Back 23

LDPE

Front 24

The diffusion of atoms of similar size depends upon the presence of __________.

Back 24

vacancies

Front 25

The entropy of a perfect crystal at absolute zero kelvin with the atoms at rest is equal to _____.

Back 25

zero

Front 26

A mole of pure argon gas has ____ entropy than a mixture of a half mole of argon and a half mole of neon.

Back 26

less

Front 27

What has the greater entropy, ice or water?

Back 27

water

Front 28

When the equilibrium concentration of vacancies is present in a crystal at constant temperature and pressure, the Gibbs free energy is at a(n) _______.

Back 28

minimum

Front 29

The probability that the energy to create a vacancy in a crystal is present in excess of the average energy in the crystal is given by the ______________ probability distribution.

Back 29

Maxwell-Boltzmann

Front 30

If at constant temperature and pressure a change in a system produces a negative change in the Gibbs free energy, the change is ____________.

Back 30

spontaneous

Front 31

The rate of change in a system depends upon the ___________ enthalpy.

Back 31

activation

Front 32

If the natural logarithm of the rate of a thermally activated process is plotted on the y-axis as a function of the inverse of the absolute temperature on the x-axis, the slope of this plot is equal to the __________________ divided by Boltzmann’s constant.

Back 32

activation enthalpy

Front 33

The activation enthalpy for vacancy diffusion contains two contributions: the activation enthalpy for vacancy _________ and atom migration.

Back 33

formation

Front 34

Which would have the higher activation energy for diffusion, carbon in iron or nickel in iron? The atomic radius of carbon is 0.077 nm, the atomic radius of nickel is 0.124 nm, and the atomic radius of iron is 0.124 nm.

Back 34

Nickel in iron

Front 35

The activation enthalpy for self-diffusion is directly related to the strength of chemical _________.

Back 35

bonding

Front 36

The internal energy of a material does not depend upon which of the following?
(a) Energy of defects in the material
(b) Kinetic energy of the vibrating atoms
(c) Bond energy between atoms
(d) Net energy resulting from a history of heating and cooling

Back 36

(d) Net energy resulting from a history of heating and cooling

Front 37

The sequence from (a) to (d) in this question should be from high thermal conductivity to low thermal conductivity. Which material is out of sequence?
(a) OUHMWPE fibers parallel to the fiber axis
(b) PMMA
(c) HDPE
(d) LDPE

Back 37

(b) PMMA

Front 38

Which of the following does not result in high thermal conductivity?
(a) Strong bonding
(b) Free electrons
(c) Grain boundaries
(d) Small interatomic distances

Back 38

(c) Grain boundaries

Front 39

Which of the following material states has the highest entropy?
(a) Amorphous solid
(b) Vapor
(c) Liquid
(d) Single crystal

Back 39

(b) Vapor

Front 40

Which of the following is not a state thermodynamic variable?
(a) The Gibbs free energy
(b) Entropy
(c) Heat
(d) Enthalpy

Back 40

(c) Heat

Front 41

The mixing of which pair of the following atoms does not occur by vacancy diffusion?
(a) Gold and silver
(b) Copper and nickel
(c) Platinum and palladium
(d) Hydrogen and palladium

Back 41

(d) Hydrogen and palladium

Front 42

Which of the following polymer combinations is least likely to mix?
(a) Liquids of two different long-chain molecules with a positive enthalpy of mixing.
(b) A liquid solvent and solid polymer with solubility parameters of 19 MPa0.5 and 20 MPa 0.5 respectively.
(c) Liquids of two different long-chain molecules with a negative enthalpy of mixing.
(d) Liquids of two different short molecules with a positive enthalpy of mixing

Back 42

(a) Liquids of two different long-chain molecules with a positive enthalpy of mixing.