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Properties of Water Notes: Honors Biology

The document discusses the properties and structure of water molecules. It explains that water is a polar molecule due to the unequal sharing of electrons between the oxygen and hydrogen atoms. This polarity allows water to form hydrogen bonds between molecules. The polarity and hydrogen bonding give water unique properties including being a versatile solvent, having high heat capacity and heat of vaporization, and changing density when freezing. These properties are important for maintaining homeostasis in living things.

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396 views15 pages

Properties of Water Notes: Honors Biology

The document discusses the properties and structure of water molecules. It explains that water is a polar molecule due to the unequal sharing of electrons between the oxygen and hydrogen atoms. This polarity allows water to form hydrogen bonds between molecules. The polarity and hydrogen bonding give water unique properties including being a versatile solvent, having high heat capacity and heat of vaporization, and changing density when freezing. These properties are important for maintaining homeostasis in living things.

Uploaded by

Pavan
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Properties of Water Notes

Honors Biology
Water in Living Things
One Example of Homeostasis
Organisms remove excess
heat through water
evaporation, while also
maintaining heat with water.
This allows organisms to
maintain a constant internal
temperature which is one
example of maintaining
homeostasis.
Properties due to Water’s Polarity
1. Versatile solvent
2. Cohesion
Example: surface tension
3. Adhesion
Example: capillary action
4. Specific Heat/Heat Capacity
5. Heat of Vaporization
6. Freezing
Structure of the Water Molecule
 The molecular
formula for water is
H2O.
 It consists of 2
hydrogen atoms and
1 oxygen atom.
 Covalent bonds
connect hydrogen
and oxygen.
Why is Water Polar?

 Water is a polar molecule, meaning that


there is an unequal distribution of
electrons. Let’s look at electronegativity.
 Oxygen is partially negative, and hydrogen
is partially positive.
What is Hydrogen Bonding?
 The hydrogen atom from one water molecule bonds
weakly to the oxygen atom of another water molecule
through a hydrogen bond.
Properties due to Water’s Polarity
1. Versatile solvent
2. Cohesion
Example: surface tension
3. Adhesion
Example: capillary action
4. Specific Heat/Heat Capacity
5. Heat of Vaporization
6. Freezing
What is the Versatile Solvent?
 Polarity of the water molecule means that it can attract
other molecules that are charged or polar.
 Water can also dissociate ionic bonds. NOTE: This is not
a chemical reaction.
 Hydrophilic – molecules that are polar/have a charge
and; therefore, attracted to water
 Hydrophobic – molecules that are nonpolar/don’t
possess a charge and; therefore, are not attracted to water
What is Cohesion?
 Water is attracted to other water molecules
due to hydrogen bonding.
 The oxygen end of water has a negative charge
 The hydrogen end has a positive charge.
What is Adhesion?
 Water is attracted to other substances that are
polar or have charges due to hydrogen
bonding.
 Capillary action is limited by gravity
Specific Heat in Water
 Review: What are the common states of matter and the
transitions between them?
 High Specific Heat/Heat Capacity - water temperature
changes slowly and holds temperature well.
 Why? Hydrogen bonds require an input of energy to
break therefore requiring more energy for water to
change states of matter than non-polar or non-charged
molecules
Heat of Vaporization
 High Heat of Vaporization - Water requires a lot of
energy to vaporize. When organisms sweat or dogs pant,
they release a high amount of heat energy.
 Why? Hydrogen bonds require an input of energy to
break therefore requiring more energy for water to
change states of matter than non-polar or non-charged
molecules
Density Changes
 Water is less dense in solid form – Solid water
molecules form a lattice that is less dense then liquid
water and therefore floats.
 Why? The partial positive hydrogens must face the
partial negative oxygens of adjacent water molecules for
the most stable structure since molecules are not sliding
past one another in a solid.
Properties due to Water’s Polarity
1. Versatile solvent
2. Cohesion
Example: surface tension
3. Adhesion
Example: capillary action
4. Specific Heat/Heat Capacity
5. Heat of Vaporization
6. Freezing

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