Changes of State - Belle Vernon Area School District
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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.