Water the Magic Molecule of Life

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• Convert the following:
• 24.3 ml to kl
• 23Mg to cg
Water the Magic Molecule of Life
The Polarity of Water Molecules
• The Unequal sharing of Electrons in a covalent
molecule results in a polar molecule
Cohesion
• This is the attraction of molecules of water to each
other due to hydrogen bonding
– In plants it helps them pull the water molecules up
against gravity
Adhesion and Surface Tension
Water Has a High Specific Heat
• Specific heat- The amount of heat it takes to
change the temperature of 1 g of a substance
1°C
– Calorie- the amount of heat necessary to raise 1g
of water 1°C
– Hydrogen bonding dampens the effect of heating
thus causing the high specific heat
Evaporative Cooling
Ice vs Water
Ice is less dense thus it is floating an insulating the water below
Solvent of Life
• Aqueous solutions have water as the solvent
– Hydration shell is the hydrogen side surrounding anions
and oxygen side surrounding cations in solution
– Non-ionic compounds can also dissolve if they have
polar regions or ionic bonds on their surface
Acidic and Basic Solutions