properties of water notes
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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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