Water Properties Flashcards
Chemical Nature of Water
Polar:
Due to dipoles formed between Hydrogens and electronegative oxygen
(this is not H-bonding, these are covalent bonds)
Reason for H-Bonding of Water
Occurs due to the dipoles formed by the polarity of water
–> Opposing poles of each water molecule attract each other forming H-Bonds
NOTE: H-Bonds are between MOLECULES, NOT within the water molecule itself
List Properties of Water
1) Adhesion
2) Cohesion
3) High Specific Heat
4) High Heat of Vaporization
5) Floating of Ice
6) Solvent of life
Adhesion vs Cohesion
Adhesion = The clinging of water to other substances (“Sticking to other stuff”)
Cohesion = The linking together of water molecules to each other (“Sticking to itself”)
–> A result of large number of H-Bonds between water molecules
Importance of Cohesion
Leads to water’s high surface tension (allows insects to walk on water)
Causes water chains to form: Where one water goes, the rest go –> Pull each other with them
Importance of Adhesion
Allows for capillary action (Allows for water to travel up roots to leaves, against gravity)
Moderation of Temp
Water is an effective “heat bank”: Can absorb or release a lot of heat with only a small change to its own temp.
High Specific Heat
Specific Heat = The amount of heat needed to change its temp by 1C
–> A result of it being more difficult to break the large amount of H-Bonds
High Specific Heat Importance
–> Allows water temp to remain quite stable (good for life)
Ex: Body of water can absorb and store large amounts of heat from the sun without warming up the water too much (moderates air temp in coastal regions)
High Heat of Vaporization
The quantity of heat water must absorb for 1g of it to evaporate
–> Again, due to it being more difficult to break all the H-Bonds
High Heat of Vaporization Importance
Ex: It’s why we sweat –> Water evaporates and takes its heat with it, cooling down surfaces
Floating of Ice
Water’s solid form is less dense than its liquid form as it EXPANDS WHEN FROZEN
–> Due to a crystalline lattice structure forming which holds H-Bonds farther apart and keeps water molecules at a greater distance from each other
Floating of Ice Importance
Allows aquatic life to not die:
Prevents bodies of water from freezing all the way to the bottom, instead all the ice floats up to the surface, allowing life to continue on below it
Solvent of Life
Water is a very versatile solvent due to its polar nature
–> Can dissolve many substances
Ex: Make blood and plant sap possible which are essential to life
Hydrophyllic
LOVES water: dissolves in water (or in some cases absorbs it like cotton does)
