Lectures 1-4

Question 1

LDF (London Dispersion Forces)

Answer 1

The force of attraction that arises as a result of temporary dipoles induced in the atoms of molecules

Question 2

Hydrogen Bonding

Answer 2

A type of dipole-dipole interaction between the hydrogen atoms in a polar bond and an unshared electron pair of an element that is very electronegative; must be N, O, or F

Question 3

Dipole-Dipole

Answer 3

Forces that occur between polar molecules

Question 4

Ion-Dipole

Answer 4

Experienced by ions interacting with polar molecules in solution

Question 5

Dipole-Induced Dipole Forces

Answer 5

Exists when a polar molecule induces a dipole on a nonpolar molecule due to proximity

Question 6

Polarizability

Answer 6

Measure of ease with which electron charge density is distorted by an external electric field: reflects the ability for which a dipole can be induced

Question 7

Adhesion

Answer 7

The ability to “stick” to things (like glass) other than itself

Question 8

Cohesion

Answer 8

The ability to “stick” to itself

Question 9

Viscosity

Answer 9

Resistance to flow exhibited by all liquids and gases

Question 10

Surface Tension

Answer 10

Resistance of a liquid to increase in its surface area

Question 11

Capillary Rise

Answer 11

Spontaneous rising of a liquid up a narrow tube

Question 12

Triple point

Answer 12

The point on the phase diagram at which all three states of matter exist (and are in equilibrium)

Question 13

Critical Point

Answer 13

The point on the phase diagram where the liquid and gaseous states are indistinguishable

Question 14

Supercritical Fluid

Answer 14

Any substance at a temperature and pressure above its critical point

Question 15

Molecular Solids

Answer 15

Solids (like ice) that are held together by intermolecular forces like LDF, Dipole-Dipole, Ion-Dipole, etc.; low melting point and nonconducting

Question 15

Ionic Solids

Answer 15

Ionic bonds (oppositely charged ions) hold the solid in a regular three dimensional arrangement; high melting point, brittle, and hard

Question 16

Covalent Network

Answer 16

A solid consists of atoms held together in large networks or chains by covalent bonding (electrons pairs are shared between atoms); high melting point, hard, and nonconducting

Question 17

Metallic Solids

Answer 17

Similar to a covalent network, but with metals; variable hardness and melting, and high conductivity

Question 18

Allotrope

Answer 18

Some solid substances can exist in more than one form (diamond, coal, graphite)

Question 19

Solubility

Answer 19

The maximum amount of a solute (dissolved substance) that is dissolved in a solvent (the substance dissolving dissolved substance) at a given temperature

Question 20

Saturated Solution

Answer 20

Contains the maximum amount of dissolved solute for a given amount of solvent at a specific temperature and pressure

Question 21

Supersaturated Solution

Answer 21

Contains more dissolved solute than a saturated solution (more than the solvent is able to handle)

Question 22

Dilute Solutions

Answer 22

Contains less dissolved solute than a saturated solution (could dissolve more solute if needed)

Question 23

Strong Electrolyte

Answer 23

Complete dissociated into ions in a solution

Question 24

Weak Electrolytes

Answer 24

Produce few ions and do not dissociate completely in a solution

Question 25

Nonelectrolyte

Answer 25

Will not produce ions

Question 26

Miscible

Answer 26

Two liquids which share intermolecular forces and are able to mix with one another

Question 27

Immiscible

Answer 27

Two liquids that do not have intermolecular forces in common and will not mix with one another

Question 28

Q = mc∆T

Answer 28

m = mass
c = specific heat
∆t = change in temperature
Used to solve when temperature is changing

Question 29

Q = n∆H

Answer 29

n = moles
∆H = enthalpy
Used to solve when temperature is stable

Question 30

Clausius Clapeyron

Answer 30

ln(P2/P1)=(-∆Hvap/R)(1/T2-1/T1)
R = 8.314 J/mol K
Pressure is directly related to temperature

Question 31

Unit Cells

Answer 31

Finding out the number of atoms in a unit cell:
d = (# atoms / unit cell) (MW/Na)(1/Vc)
d = density
# atoms / unit cell = number of atoms per unit cell
MW = molecular weight
Na = Avogadro’s number (6.022 X 10^23)
1/Vc = Reciprocal of the volume

Question 32

Unit Cells (continued)

Answer 32

Simple Cubic: One cell on each corner (there is 1 atom total); edge length formula: a = 2r
Body Centered Cubic: One cell on each corner and anther right in the middle (there are 2 atoms total); edge length formula: a = 4r/sqrt3
Face Centered Cubic: One cell on each corner and one in the middle of each face (there are 4 atoms total); edge length formula: a = 2r(sqrt2)

Question 33

Henry’s Law

Answer 33

C = kp
C = gas solubility (M)
P = partial pressure
K = Henry’s law constant
Normally asked to find k using this formula