Transcript Changes of State - Belle Vernon Area School District

10.4
 Phase
– any part of a system
with uniform composition and
properties.
 Condensation – gas changes
to a liquid
 Molecules of liquid can
evaporate and then condense
and re-enter the liquid phase



Condensation and evaporation
can happen at the same rate…
Equilibrium – a dynamic
condition in which 2 opposing
changes occur at equal rates
in a closed system
No net change in amt. of
substance in either phase.
P
is directly proportional to [ ]
 Equilibrium vapor pressure –
pressure exerted by vapor in
equilibrium with its corresponding
liquid at a given temp
 Different for each liquid
 The higher the bonding the
_____the EVP
 Think about the KMT
 Volatile
Liquids – liquids that
evaporate readily
 __________ forces of attraction.
 Boiling – conversion of a liquid to
a vapor within the liquid as well
as at the surface
 Boiling point – the temp at which
the equilibrium vapor pressure of
the liquid = atm pressure
 The
________ the atm pressure,
the lower the b.p.
 Temp is constant while boiling
 Normal atmospheric pressure
= 1 atm, 760 torr, 101.325kPa
 E needs to be + constantly to
continue boiling
 MEV
– the amt of E as heat that
is needed to vaporize 1 mol of
liquid at the liquids b.p. at
constant pressure.
 ΔHv
 Measure of attraction of
particles
 Freezing
– physical change of
liquid to solid
 Loss of E
 Freezing point – the temp at
which solid and liquid are at
equilibrium at 1 atm
 At f. p. particles have same amt
of ave K. E.
 At
m.p. the solid and liquid
have the same amt of k.e.
also.
 For pure crystalline solids, f.p.
and m.p. are at the same
temp.
 Molar
Enthalpy of fusion – the
amount of energy as heat
required to melt one mole of
solid at the solids melting
point.