chemistry ch 11

kinetic theory

all matter is comprised of small constantly moving particles experiencing collisions in which energy is conserved (perfectly elastic)

compressibility

property of matter arising from the empty spaces among particles

fluidity

property of matter arising from the ease of movement of particles relative to each other

incompressible
not fluid

what can be said about the compressibility and fluidity of solids?

low compressibility
fluid

what can be said about the compressibility and fluidity of liquids?

high compressibility
fluid

what can be said about the compressibility and fluidity of gases?

ideal gas

PV=nRT
no attractive forces
point masses (no volume)

real gas

(P = n^2a/v)(V-nb)=nRT
a -> dependent on magnitude of attractive forces
b -> dependent on size of molecules

liquids and solids

no simple equation bc you can't neglect/fix two things:
1) IMFs
2) particle size (relative to volume)

sublimation

solid to gas

deposition

gas to solid

condensation

gas to liquid

vaporization/evaporation

liquid to gas

melting/fusion

solid to liquid

freezing/crystallization

liquid to solid

vapor pressure

the equilibrium partial pressure of the vapor over the liquid (or solid) at a given temperature (ex: Pwater)

maxwell-boltzman distribution graph

graph that shows us liquid to gas phases, where the area under the curve is the # of particles able to escape into the gas phase

boiling point

temperature at which the Pvap of the liquid is equal to the pressure on the liquid surface (Patm unless the vessel is closed)

normal boiling point

T at which Pvap = 1 atm = 760 mmHg

freezing point

temperature at which the pure liquid changes to a crystalline solid

melting point

temperature at which the pure crystalline solid changes to a liquid

pressure changes

freezing and melting point are both virtually unaffected by ...

molecular

which type of substance is the easiest to melt/boil

covalent network

which type of substance is the hardest to melt/boil

temperature change to see phase changes

what does this graph show us

-phase changes
-all energy goes into changing phases not changing temperature (when it hits equilibrium

what do the horizontal lines indicate, and why does the temperature remain constant

long line > high IMF; high energy required to change phase > long line

what does the length of each line indicate

sloped line represents 1 phase
high steepness = low specific heat

what does a sloped line represent?
and what does the steepness indicate about specific heat?

clausius-clapeyron equation

related Pvap to Tk of its liquid

NOTE: slope: negative; use R= 8.31 J/mol K
need to find B value for each substance
ln P = (-change in Hvap/R) (1/T) + B

two point form

use the log form at two T's, T1 and T2 and subtract equations

ln (P2/P1) = change in Hvap/R (1/T1 - 1/T2)

1 atm or 760 mmHg

if a problem says normal boiling point in it that means the pressure = ...

phase diagram

a graphic to summarize the conditions, T and P, under which different states of a substance are stable

area regions

condition where a given phase is stable

line segments

conditions where two phases exist in equilibrium

specific heat

the quantity of heat required to raise the temperature of one gram of a substance by one Celsius degree

triple point (TP)

conditions where all three phases exist in equilibrium

critical point (CP)

T above which the liquid does not exist regardless of the pressure (Ek has totally overcome all attractive forces)

surface tension

energy required to increase the surface area of liquid by a unit amount; results from the net force toward the interior of the liquid experienced by a surface molecule

capillary rise

phenomenon related to the surface tension
-water molecules attract to glass, bc of this attraction, a thin film of water starts to move up inside of the glass capillary, thus making a meniscus

viscosity

the resistance to flow that is exhibited by all liquids and gases

liquid is slow

high viscosity, really viscous

easy to pour

low viscosity

imfs

the forces of interaction between molecules
(typically weakly attractive; abt 100 to 1000 times smaller than bond energies)

van der waals forces

weak attractive forces (LDF and dipole-dipole)

london dispersion forces

weak intermolecular attractive forces resulting from the small, instantaneous, synchronized dipoles occurring due to the varying positions of the electrons of the electrons as they move about the nuclei

increase w molar mass

ldfs tend to

polarizable

larger atoms are more

polarizable

molecules that are more spread out tend to be more

dipole dipole forces

one polar molecule's partial positive charge is attracted to the partial negative of another polar molecule

stronger

LDF is __ than DD but DD is permanent

weak Pvap
strong surface tension
high normal boiling points
high viscosity

strong IMFS yield

ion dipole

the attractive force between a polar molecule and a charge particle ion
-the attraction must be between a partial negative and cation or partial positive and anion

hydrogen bonding

a weak to moderate attractive force that exists between an H atom covalently bonded to an N, O, or F atom and an N, O, or F atom on another molecule

hydrogen bonding

___ receives its strength from the partial exposure of the proton of the H nucleus when it is bonded to a highly electronegative atom

molecular

consists of atoms or molecules held together by IMFS; NM/NM

metallic

consists of positive cores of atoms held together by a "sea" of mobile electrons; M

ionic

consists of cations and anions held together by the electrical attraction of opposite charges; M/NM

covalent network

consists of atoms held together in large 3D or 2D networks or chains

C (diamond)
C (graphite)
C60
SiO2
SiC

five covalent networks

LDF, DD/HB, Ionic/Metallic, Covalent Network

list all the force and bond types in order from weakest to strongest

-high melting points
-brittle, hard
-poor conductors of heat and electricity
-dull

ionic solid characteristics

-low melting points
-nonconductors
-soft
-dull

molecular solid characteristics

-HIGHEST melting points
-hard
-dull
-nonconductors

covalent solid characteristics

-variable hardness and melting points (depends on strength of metallic bonding)
-conductors
-lustrous
-ductile
-malleable

metallic solid characteristics

molecular < ionic ~~ metallic < covalent

the general order of increasing strength of interactions in a solid is