Chapter 10 Vocab

Question 1

condensed state

Answer 1

a state of matter in which particles are in contact with one another; normally refers to liquids and solids.

Question 2

intermolecular forces

Answer 2

relatively weak interactions that occur between molecules.

Question 3

dipole-dipole attraction

Answer 3

the attractive force resulting when polar molecules line up so that the positive and negative ends are close to each other.

Question 4

hydrogen bonding

Answer 4

unusually strong dipole-dipole attraction that occur among molecules in which hydrogen is bonded to a highly electronegative atom.

Question 5

London dispersion forces

Answer 5

the forces, existing among noble gas atoms and nonpolar molecules, that involve an accidental dipole that induces a momentary dipole in a neighbor.

Question 6

surface tension

Answer 6

the resistance of a liquid to an increase in its surface area.

Question 7

capillary action

Answer 7

the spontaneous rising of a liquid in a narrow tube.

Question 8

viscosity

Answer 8

the resistance of a liquid to flow.

Question 9

crystalline solid

Answer 9

a solid with a regular arrangement of its components.

Question 10

amorphous solid

Answer 10

a solid with considerable disorder in its structure.

Question 11

lattice

Answer 11

a three-dimensional system of points designating the positions of the centers of the components of a solid (atoms, ions, or molecules).

Question 12

unit cell

Answer 12

the smallest repeating unit of a lattice.

Question 13

X-ray diffraction

Answer 13

a technique for establishing the structure of crystalline solids by directing by X rays of a single wavelength at a crystal and obtaining a diffraction pattern from which interatomic spaces can be determined.

Question 14

ionic solid

Answer 14

a solid containing cations and anions that dissolves in water to give a solution containing the separated ions which are mobile and thus free to conduct electricity current.

Question 15

molecular solid

Answer 15

a solid composed of neutral molecules at the lattice points.

Question 16

atomic solid

Answer 16

a solid that contains atoms at the lattice points.

Question 17

closest packing

Answer 17

an arrangement in which uniform, hard spheres are packed in a manner that most efficiently uses the available space.

Question 18

hexagonal closest packed (hcp) structure

Answer 18

a structure composed of closest packed spheres whit an ababab arrangement of layers; the unit cell hexagonal.

Question 19

cubic closest packed (ccp) structure

Answer 19

a solid molecule by the closest packing of spheres with an abcabc arrangement of layers; the unit cell is face centered cubic.

Question 20

band model

Answer 20

a molecular model for metals in which electrons are assumed to travel around the metal crystal in molecular orbitals formed from the valence atomic orbitals of the metal atoms.

Question 21

molecular orbital (MO) model

Answer 21

a model that regards a molecule as a collection of nuclei and electrons, where the electrons are assumed to occupy orbitals much as they do in atoms, but having the orbitals extend over the entire molecule. In this model the electron are assumed to be delocalized rather than always located between a given pair of atoms.

Question 22

alloy

Answer 22

a substance that contains a mixture of elements and has metallic properties.

Question 23

substitutional alloy

Answer 23

some of the host metal atoms are replaced by other metal atoms of similar sizes.

Question 24

interstitial alloy

Answer 24

formed when the small holes (interstices) in a metallic crystal are filled with smaller atoms.

Question 25

network solid

Answer 25

an atomic solid containing strong directional covalent bonds.

Question 26

silica

Answer 26

the fundamental silicon-oxygen compound, which has the empirical formula SiO2, and forms the basis of quarts and certain types of sand.

Question 27

silicate

Answer 27

salts that contain metal cations and polyatomic silicon-oxygen anions that are usually polymeric.

Question 28

glass

Answer 28

an amorphous solid obtained when silica is mixed with other compounds, heated above its melting point, and then cooled rapidly.

Question 29

ceramic

Answer 29

a nonmetallic material made from clay and hardened by firing at high temperature; it contains minute silicate crystals suspended in a glassy cement.

Question 30

semiconductor

Answer 30

a conductor made with semiconducting material.

Question 31

n-type semiconductor

Answer 31

a substance whose conductivity is increased by doping it with atoms having more valence electrons than the atoms in the host crystal.

Question 32

p-type semiconductor

Answer 32

semiconductors doped with atoms having fewer valence electrons than the atoms of the host crystal.

Question 33

p-n junction

Answer 33

connection of p and n type semiconductors.

Question 34

vaporization (evaporation)

Answer 34

the changes in state that occur when a what liquid evaporates to form a gas.

Question 35

heat of vaporization

Answer 35

the energy required to vaporize one mole of a liquid at a pressure of one atmosphere.

Question 36

enthalpy of vaporization (ΔHvap)

Answer 36

the energy required to vaporize 1 mole of a liquid at a pressure of 1 atm.

Question 37

condensation

Answer 37

the process by which vapor molecules reform a liquid.

Question 38

equilibrium

Answer 38

a state of balance; when the concentration of a solute is the same throughout a solution.

Question 39

equilibrium vapor pressure

Answer 39

the pressure of the vapor pressure present at equilibrium.

Question 40

sublimation

Answer 40

the process by which a substance goes directly from solid to the gaseous state without passing through the liquid state.

Question 41

heating curve

Answer 41

a plot of temperature versus time for a substance where energy is added at a constant rate.

Question 42

enthalpy (heat) of fusion (ΔHfus)

Answer 42

the enthalpy change that occurs to melt a solid at its melting point.

Question 43

normal melting point

Answer 43

the temperature at which the solid and liquid states have the same vapor pressure under conditions where the pressure on system is one atmosphere.

Question 44

normal boiling point

Answer 44

the temperature at which the vapor pressure of a liquid is exactly one atmosphere.

Question 45

supercooled

Answer 45

the process of a cooling a liquid below its freezing point without its changing to a solid.

Question 46

superheated

Answer 46

the process of heating a liquid about its boiling point without its boiling.

Question 47

phase diagram

Answer 47

a convenient of representing the phase of a substance in a closed system as a function of temperature and pressure.

Question 48

triple point

Answer 48

the point on a phase diagram at which all three state of a substance are present.

Question 49

critical temperature

Answer 49

the temperature above which can not be liquefied no matter what pressure is applied.

Question 50

critical pressure

Answer 50

the minimum pressure required to produce a liquefaction of a substance at the critical temperature

Question 51

critical point

Answer 51

the point of a phase diagram at the temperature and pressure have their critcal values; the end point of the liquid-vapor line.