Koligativne lastnosti

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Koligativne lastnosti

• 3. vaja

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Raztopine

• Homogene zmesi dveh ali vec molekulskih ali
  ionskih vrst.

(1) topilo (2) topljenec
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Koligativne lastnosti

• Znianje parnega tlaka topila
• Zvianje vrelica topila
• Znianje zmrzica topila
• Osmoza

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Znianje parnega tlaka
n2
?p1

• Raoultov zakon

x2
n1 n2
p10
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Zvianje vrelica
i vant Hoffov faktor
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Znianje zmrzica
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Fazni diagram za vodo (polna crta) in vodno
raztopino nehlapnega topljenca (crtkana crta).
http//intro.chem.okstate.edu/1515SP01/Lecture/Cha
pter13/SolutionPhaseDiagram.html
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Osmozni tlak
? ? g h i c R T
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Reverzna osmoza
Reverzna osmoza prehajanje vode skozi
polprepustno membrano s podrocja z vecjo
koncentracijo topljenca na podrocje z manjo
koncentracijo topljenca pod vplivom tlaka (P
gtosmotski tlak). Uporablja se za razsoljevanje
morske vode, ultrafiltracijo.
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Osmolarnost, osmolalnost
selektivno prepustna membrana (prepuca ureo)
saharoza 0,5 M
saharoza 1,0 M
saharoza 0,5 M
saharoza 0,5 M
urea 0,5 M
urea 0,5 M
A
B
x
y
H2O ?
H2O ? H2O
urea ?
urea ?
A je izoosmotska in hipotonicna glede na B
x je hiperosmotska in izotonicna glede na y
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(No Transcript)
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Osmosis and Red Blood Cells
The fluids flowing in the inner part of an
organism like the blood plasma must have a
concentration of solutes that are within a very
narrow range. The Figure below shows what happens
to the red blood cells immersed in solutions of
varying molality. Isotonic - the cells were
diluted in serum. Blood serum is isotonic with
respect to the cytoplasm, and red cells in that
solution assume the shape of a biconcave disk.
Hypotonic - the cells in serum were diluted in
water at 200 milliosmols (mOs), the cells are
visibly swollen and have lost their biconcave
shape, and at 100 mOs, most have swollen so much
that they have ruptured, leaving the red blood
cell ghosts. Hypertonic - A concentrated
solution of NaCl was mixed with the cells and
serum to increase osmolarity At 400 mOs and
especially at 500 mOs, water has flowed out of
the cells, causing them to collapse and assume
the spiky appearance.
Washing out salts from the organism results in
over inflation and bursting the cells
Dehydration results in shrinking of cells
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• http//www.stolaf.edu/people/giannini/flashanimat/
  transport/osmosis.swf
• hemodializa
• http//www.kidneypatientguide.org.uk/site/HDanim.p
  hp
• http//taste.merlot.org/portal/health_sciences/ani
  mation.htm
• naloge
• http//arbl.cvmbs.colostate.edu/hbooks/cmb/cells/p
  memb/osmosis_eg.html

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Koligativne lastnosti elektrolitov
i izmerjena kolig. lastnost / izracunana kolig.
lastnost

• Neelektroliti i1
• Mocni elektroliti iN ali iN ?
• ibki eletroliti
• HA ? H A-

Izmerjena lastnost (1- ? ? ?)/ V ali (1-?
N?)/ V
1-? ? ?
Izracunana lastnost (N1) 1/ V
i 1 ? (N - 1)