COLLIGATIVE PROPERTIES Flashcards
What are the physical properties of substances?
Colligative Properties
Additive Properties
Constitutive Properties
Colligative Properties - depend mainly on the ______ in a solution.
number of particles
Colligative Properties:
Osmotic Pressure, Vapor Pressure Lowering,
Freezing Point Depression, Boiling Point Elevation
Additive Properties - depend on the ______ of the atoms in the molecule or on the
______ of the constituents in a
solution.
total contribution; sum of the properties
Additive Properties:
Molecular Weight
Constitutive Properties - depend on the ____ and to a lesser extent on the ___
and ____of atoms within a molecule
arrangement; number; kind
Constitutive Properties:
Refractive Index, Optical Rotation, Solubility
depend mainly on the
number of particles in a solution.
Colligative Properties
depend on the total contribution of the atoms in the molecule or on the
sum of the properties of the constituents in a
solution.
Additive Properties
depend on the arrangement and to a lesser extent on the number
and kind of atoms within a molecule
Constitutive Properties
On adding a solute to a solvent, the properties of
the solvent are ____
modified.
Vapor pressure -
Freezing point -
Boiling point -
decreases
decreases
increases
Colligative Properties depend only on the
____ of solute particles relative
to solvent particles, not on the ____ of solute particles.
NUMBER; KIND
is the pressure of the saturated vapor
above a liquid resulting from the escape of the surface
liquid.
Vapor Pressure
the vapor pressure of an ideal solution is dependent on the
______ of each _____ and the _____ of the component present in the solution.
vapor pressure; chemical component; mole
fraction
When a nonvolatile solute is combined with a volatile
solvent, the vapor above the solution is provided solely by the
___
solvent.
´ The ____ reduces the escaping tendency of the solvent and, on
the basis of ____
solute; Raoult’s Law
The vapor pressure of a solution
containing a nonvolatile solute is
lowered _____to the
relative number of the solute
molecules.
Raoult’s Law; proportional
According to Raoult’s Law, the _____ over a dilute solution is ____
to the _____,
times the _____ in the
solution .
vapor pressure
of a solvent; equal; vapor pressure of the pure solvent; mole fraction of solute
X2 =
mole fraction of solute
pi o =
vapor pressure of the pure
solvent
is used to measure
the pressure difference of the
vapor pressure between the
solution and the pure
solvent.
Manometer
Manometer is used to measure
the pressure difference of the
vapor pressure between the
_____ and the _____.
solution; pure
solvent
For dilute aqueous solutions,
however, the vapor pressure
lowering is so _____ as to
produce a _____ in the
measurement.
slight; serious error
_______small differences in vapor pressure.
Accurate differential manometers
is used
frequently for the precise
determination of vapor pressures.
isopiestic method
- when a nonvolatile solute is added
to a volatile solvent, the solute
reduces the escaping tendency of
the solvent, thus, - the VP of the solution is _________
proportional to the relative number
of solute molecules.
lowered
´Is the temperature at
which the vapor pressure
of the liquid becomes
equal to the external
atmospheric pressure
Boiling Point
The boiling point of a solution
of a nonvolatile solute is
____ than that of the pure
solvent, (solute ____ the
vapor pressure of the solvent).
higher; lowers
´In the _____, the
vapor and the boiling
solvent are pumped by
the force of ebullition
through a glass tube
and sprayed over the
thermometer bulb to
obtain an invariant
equilibrium temperature.
Cottrell boiling
point apparatus
the phenomenon that theboiling pointof
aliquid(asolvent) will be higher when
another compound is added, meaning
that asolutionhas a higher boiling point
than a pure solvent.
BOILING POINT ELEVATION
BOILING POINT ELEVATION happens whenever a _____, such as a _____, is added to a ____, such as water.
non-volatile
solute; salt; pure
solvent
The boiling point can be measured
accurately using an
ebullioscope
symbol of the molal boiling point
elevation constant or the
ebullioscopic constant
kb
EBULLIOSCOPE FORMULA
∆Tb = kbm
Ebullioscopic
Constant:
0.52 degC/mole
- the BP of a solution containing a
nonvolatile solute would be ______
that the pure solvent because the
solute would _______ the vapor
pressure of the solvent
HIGHER; LOWER
the phenomenon in which the freezing
pointof aliquid(asolvent) is depressed
when another compound is added,
meaning that asolution has a lower
freezing point than a pure solvent.
FREEZING POINT DEPRESSION
FREEZING POINT DEPRESSION phenomenon may be observed
in _____, which due to its salt
content remains liquid at
temperatures below____,
the freezing point of _____.
sea water; 0°C (32°F); pure water
The ______ of air-free water, at
which solid, liquid, and vapor are in
equilibrium, lies at a pressure of ____and a temperature of ______
triple point; 4.58
mmHg; 0.0098
°C.
´If a solute is dissolved in the liquid at
the _____, the escaping
tendency or vapor pressure of the
liquid solvent is ______ below that of
pure solid solvent.
triple point; lowered
The temperature must _____ in order
to reestablish equilibrium between the
liquid and the solid.
drop
Methods for the Determination of
Freezing Point Lowering
1.Beckmann method
2.The Equilibrium method.
´It consists of a jacketed tube with a
sidearm through which the test
material may be introduced.
Beckmann method
is
supported in the tube and extends
into the test solution.
Beckmann thermometer
´In carrying out a determination, the
temperature is read on the
______
at the freezing point of the pure
solvent, water.
Beckmann differential thermometer
A ____ is
introduced into the apparatus,
containing a _____,
and the freezing point of the solution
is read and recorded.
known weight of the solute; given weight of solvent
The freezing point of a solution is ____ than that of the
pure solvent
LOWER
COMMON APPLICATIONS OF FREEZING POINT DEPRESSION
Propylene glycol
Ethylene
glycol –
deadly to
small
animals
solutions have a _________ FP that the
pure solvent.
LOWER
the cryoscopic constant:
1.86
degC/molal
FORMULA FOR FREEZING POINT DEPRESSION:
∆Tf = kfm
SYMBOL FOR the molal FP elevation
constant or the cryoscopic
constant
kf
molality solution =
moles of solute / kg of solvent
Tf=
(Freezing point of pure solvent) - (Freezing point of solution)
the spontaneous net movement of water
across a semipermeable membrane from a
region of high to low water concentration.
OSMOSIS
is the movement of solvent through a semi
permeable membrane that allows only solvent to
move through it.
Osmosis
is the pressure which needs to be
applied to a solution to prevent the
inward flow of water across a
semipermeable membrane.
Osmotic pressure
The phenomenon of osmotic pressure
_____ from the tendency of a pure
solvent to move through a _____ and into a
solution containing a solute to which the
membrane is _____.
arises; semi
permeable membrane; impermeable
All aqueous solutions of non-volatile
solutes exert an
osmotic pressure
is the opposite of
water potential, which is the degree to
which a solvent tends to stay in a
liquid.
Osmotic Potential
is based
on the principle of thistle tube.
Osmometer
Osmometer is based
on the principle of
thistle tube
Van’t Hoff Equation
¶V= Nrt or ¶=mRT
¶
osmotic pressure in atm
V
volume of solutions in Liters
n
number of moles of solute
R is the gas constant equal to
0.08205L atm/mole
T
absolute temperature in °K
____ concluded that there
was an apparent analogy
between solutions and gases and
that the osmotic pressure in a
dilute solution was equal to the
pressure that the solute would exert
if it were a gas occupying volume.
Van’t Hoff
Van’t Hoff equation Corresponded to the equation for
ideal gas
Morse Equation
¶= MRT
is an important factor
affecting cells.
Osmotic pressure
is the homeostasis mechanism
of an organism to reach balance in osmotic
pressure.
Osmoregulation
is the presence of a solution that
causes cells to shrink.
Hypertonicity
is the presence of a solution that
causes cells to swell.
Hypotonicity
is the presence of a solution that
produces no change in cell volume.
´Isotonic
