Properties of Water Flashcards
Polarity
Unequal sharing of electrons make water a polar molecule
Cohesion
Attraction of molecules for other molecules of the same kind
Hydrogen bonds between H2O molecules….
hold them together and increase cohesive forces
Importance of cohesion
2
- Allows for the transport of water and nutrients against gravity in plants
- responsible for surface tension
Adhesion
Clinging of one molecule to a different molecule, due to polarity of H2O
How is adhesion useful in plants?
Allows for water to cling to the cell walls and resist the downward pull of gravity
Capillary Action
The upward movement of water due to the forces of cohesion, adhesion and surface tension
Capillary action occurs when —- is > than ——
adhesion is greater than cohesion
Temperature control
- H2O has a high specific heat (resists changes in temperature)
- Through hydrogen bonds (heat released when hydrogen bonds form)
Importance of high specific heat
- Moderates air temperature
- Stabilizes ocean temp
- Organisms can resist changes in their own internal temperature
Evaporative cooling
water has a high heat of vaporization, molecules with the highest kinetic energy leave as a gas
Importance of evaporative cooling
- Moderates earths climate
- Stabilizes temp in lakes and ponds
- Prevents terrestrial organisms from overheating
- Prevents leaves from becoming too warm in the sun
Density
As water solidifies it expands and becomes less dense
What is density due to?
hydrogen bonds
1. When cooled H2O moves too slowly to break the bonds, allowing marine life to survive
Solvent
dissolving agent in a solution, water is a versatile solvent, “like dissolves like”, due to ionic compounds
