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14/5/2015
WATER-SAHANA
2
EARTH’S WATER CONTENT
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34/5/2015
INSIDE HUMAN BODY
4
Water is the material cause of all things (Thales, 624 – 546 BC) 4/5/2015
5
COMPOSITION
Water is composed of hydrogen and oxygen.
Two volumes of hydrogen combine with one volume of oxygen
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6
STRUCTURE
An atom of oxygen is bound covalently to two atoms of
hydrogen.
Tetrahedral angle of 104.5° between the two O–H
bonds.
a) Oxygen atom has two lone electron pairs Four H bondsb) Hydrogen bonds through its two H atoms to two other water molecules (forming network)
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Inte
rmole
cula
r Fo
rces
Ionic Forces
Dipole Forces
Hydrogen Bonding
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FORCES OF ATTRACTION
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HYDROGEN BONDING
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What? Requirements
Strength
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POLARITY
Magnitude of an atom’s partial charge a measure of its polarity
Electrically polarized, Dipole moment
6 X 10-30C m gas phase. 8 X 10-30 C m) in liquid and ice
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104/5/2015
HAVE YOU EVER WONDERED?
11
SOLVENT PROPERTIES
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Universal solvent- related to polarity
Slight negative and positive charge- Makes compounds to dissociate
Sphere of Hydration
Hydrophilic Hydrophobic
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HAVE YOU EVER WONDERED?
13
THERMAL PROPERTIES
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Specific Heat• Highest• (1 calorie)• Long time to
heat and cool
Heat of Vaporization• High (586 cal)• Absorbs heat • Evaporation
Boiling and Freezing• 100oC (212oF)
and freezes at 0oC(32o F)
Water density• 4oC (36o F)–
Highly dense• Less dense
0oC(32o F)• Ice floats in
water
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HAVE YOU EVER WONDERED?
15
STATES: LIQUID, ICE AND VAPOUR
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"Phase-diag2" by Matthieumarechal
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HAVE YOU EVER WONDERED?
17
SURFACE PROPERTIES
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Surf
ace
Te
nsi
onSecond highest
Surface tensionSqueezes the liquid into the shape with the smallest possible surface area. C
ohesi
on Creates a high surface tension at the surface of the water.
Adhesi
on Wettability
Capillary action
184/5/2015
HAVE YOU EVER WONDERED?
F Persson & B Halle, JACS 135, 8735–8748 (2013).S Kaieda & B Halle, J Phys Chem B,
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WATER AND PROTEINS
Str
uct
ura
l Sta
bili
ty
Pro
tein
b
ind
ing
Funct
ion
J Qvist, M Davidovic, D Hamelberg & B Halle, PNAS 105, 6296–6301 (2008).
PDB ID code 2BOP
204/5/2015
Thank you!
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