Chapter 11 - Liquids, Solids, and IMFs

Question 1

Crystalline

Answer 1

solid with atoms or molecules in well-ordered three dimensional arrangements

Question 2

Amorphous

Answer 2

atoms have no long range order

Question 3

London Dispersion Force

Answer 3

• present in ALL molecules and atoms

Electrons will unevenly distribute as they move around creating + and - spots

• Instantaneous or temporary dipoles

Question 4

Dipole-Dipole Force

Answer 4

• in POLAR molecules

molecule with permanent electron rich and electron poor areas creating strong forces

Question 5

Permanent Dipole

Answer 5

an area of either electron rich or electron poor space creating a charge

Question 6

Miscibility

Answer 6

the ability of a substance to mix without separating into two states of liquids.

• like dissolves like
• polar into polar
• nonpolar into nonpolar

Question 7

Hydrogen Bonding

Answer 7

polar molecules with H atoms and small electron negative atoms

Question 8

Hydrogen Bond

Answer 8

FON are the strongest with H

Question 9

Ion-dipole Force

Answer 9

NOT an IMF but still very impoart!

when an ionic compound is mixed with a polar compound.

Aqueous solutions.

Question 10

Surface Tension

Answer 10

the tendency of a liquid to minimize surface area to increase stability

Question 11

Viscosity

Answer 11

the resistance of a liquid to flow.

More resistance = more viscous

Question 12

Capillary Action

Answer 12

the ability of a liquid to flow against gravity up a narrow tube.

Question 13

Vaporization

Answer 13

The transition from a liquid to a gas

Question 14

Condensation

Answer 14

The transition from a gas to a liquid

Question 15

Volatile

Answer 15

Weaker IMFs allow easy vaporization which = less stable and quicker vaporization.

• acetone

Question 16

Nonvolatile

Answer 16

liquids that due not vaporize easily have stronger IMFs

• motor oil

Question 17

Heat of Vaporization(Hvap)

Answer 17

the amount of heat required to vaporize one mole of a liquid to a gas.

Endothermic

Question 18

Dynamic Equilibrium

Answer 18

rate of vaporization = rate of condensation.

Systems always respond to minimize disturbances and return to a state of equilibrium.

Question 19

Vapor pressure

Answer 19

the pressure of a gas in dynamic equilibrium with its liquid phase.

Question 20

Boiling point

Answer 20

the temperature at which the liquids vapor pressure equals the external pressure.

Question 21

Normal Boiling Point

Answer 21

the temperature at which its vapor pressure equals 1ATM

Question 22

Clausius-Clapeyron Equation

Answer 22

the relationship between vapor pressure and temperature is exponential.

linear relationship between the natural log of the vapor pressure and the inverse of the temperature.

Question 23

Critical Temperature(Tc)

Answer 23

in a sealed containing, the temperature at which the gas and liquid become comingled creating a supercritical fluid.

Not a gas or a liquid

Question 24

Critical Pressure(Pc)

Answer 24

the pressure at which a supercritical fluid is created.

Question 25

Sublimation

Answer 25

state transition from a solid directly to a gas

Question 26

Deposition

Answer 26

going directly from a gas to a solid

Question 27

Melting point

Answer 27

molecules have enough thermal energy to overcome the IMFs that hold molecules at their stationary points.

Question 28

Melting(fusion)

Answer 28

the transition from solid to liquid. "fusing" from sever solid crystals into a continuous liquid

Question 29

Freezing

Answer 29

transition from a liquid to a solid

Question 30

Heat of Fusion(Hfus)

Answer 30

the amount of heat required to melt 1 mol of a solid endothermic process

Question 31

Phase Diagram

Answer 31

a map of the state or phase of a substance as a function of pressure(y axis) and temperature(x axis)

Question 32

Triple point

Answer 32

unique set of conditions at which the three states are equally stable and in equilibrium

Question 33

Critical Point

Answer 33

in a phase diagram it represents the temperature and pressure above which a supercritical fluid exists

Question 34

Crystalline lattice

Answer 34

the regular arrangement of atoms within a crystalline solid - minimizes energy

Question 35

Unit Cell

Answer 35

Representation of the crystalline lattice with a small collection of atoms, ions, or molecules

Question 36

Simple Cubic

Answer 36

Consist of a cube with one atom at each corner - edge length = 2r - coordination number = 6 - packing efficiency = 52%

Question 37

Coordination Number

Answer 37

the number of atoms with which each atom is in direct contact o Those an atom can strongly interact with

Question 38

Packing Efficiency

Answer 38

the % of the volume of the unit cell occupied by the spheres | o Higher coordination number = greater packing efficiency

Question 39

Body-centered Cubic

Answer 39

a cube with one atom at each corner and one atom(of the same type) in the very center of the cube o Note – atoms do not touch along the edge but instead along the diagonal line that runs from one corner through the middle of the cube to the opposite corner o L = 4r/sqrt3 o Coordination number = 8 o Packing efficiency is 68%  Strongly interacts with more atoms than in a simple cubic unit cell

Question 40

Face-Centered Cubic

Answer 40

cube with one atom at each corner and one atom(of the same kind) in the center of each cube face o Do not touch along the end of the cube but instead along the diagonal of the face o Edge length = 2sqrt(2)r o Coordination number = 12 o Packing efficiency = 74% o Any one atom interacts strongly with more atoms than either the simple cubic unit cell or the body centered cubic cell

Question 41

Hexagonal Closest Packing

Answer 41

o Layers stacks on top of each other slight off set  1st and 3rd rows mirror each other • 3rd row aligns in exactly the same way as the 1st row • ABAB o Unit cell is a hexagon instead of a cubic unit

Question 42

Cubic Closest Packing

Answer 42

o 3rd layer is offset from the first o Every 4th row aligns exactly with the first o ABCABC o Identical to the face-centered cubic unit cell structure

Question 43

Molecular Solids

Answer 43

o Solids whose composite units are molecules  H2O(s), CO2(s) o Tend to have low to moderately low melting points o Strong IMFs can increase MPs

Question 44

Ionic Solids

Answer 44

o Solids whose composite units are Ions  NaCl, CaF2 o Unit cell must be charge neutral o The more similar the radii of the cation and anion the higher the coordination number o Ionic solids tend to have much higher melting points than molecular solids  Must break Ionic bonds which are much stronger than IMFs

Question 45

Atomic Solids

Answer 45

o Solids whose composite units are individual atoms |  Xe, Fe, SiO2

Question 46

Nonbonding Atomic Solid

Answer 46

 Held together by relatively weak dispersion forces  Form closest packed structures, maximizing their coordination numbers and minimizing distance between them • Close so stronger IMFs o The only ones are noble gases in their solid form

Question 47

Metallic Atomic Solid

Answer 47

```  Held together by metallic bonds • Cations in a sea of electrons • Iron, gold, etc  Form closest packed crystal structures • Cary in bond strength ```

Question 48

Network Covalent Atomic Solid

Answer 48

 Held together by covalent bonds • Diamond, graphite, silicon dioxide  Restricted by the geometrical constraints of the covalent bonds

Question 49

Band Theory

Answer 49

o From molecular orbital theory o Applies to metallic solids and covalent solids o The gap between orbits becomes infinitely small practically making the orbits a band of energy levels o Conduction band – empty orbitals o Valence band – occupied orbitals o Energy flows continuously between conduction and valence bands which is why metals are good conductors

Question 50

Band Gap

Answer 50

o Between valence and conduction bands in insulators and semiconductors  Insulators have a large gap  Semiconductors have a small gap which can be exploited in various ways with doping

Question 51

N-type semiconductor

Answer 51

o The charge carriers are negatively charged electrons in the conduction band  Forces electrons into conduction band for charge

Question 52

P-type semiconductor

Answer 52

o Creates electron “holes” or empty molecular orbitals in the valence band o Each hole acts as a positive charge

Question 53

P-N junction

Answer 53

o Tiny spots of p-type on one side and n-type on the other | o The heart of most modern electronic devices are silicon chips with millions of these

Question 54

Diode

Answer 54

o Circuit elements that allow the flow of electrical current in only one direction