Water (Features and Importance)

Polar/dipolar

Electrons shared unevenly, one part slightly negative and one part slightly positive

Non polar

Electrons shared equally

How many degrees between the two Hydrogen ions in water

104.5

What bond is between the each water molecule

Hydrogen bond

How does a hydrogen bond form between water molecules

The delta- oxygen of one water molecule attracts to the delta+ hydrogen of a neighbouring molecule

Why does water have a high boiling point

4 weak hydrogen bonds create strong attraction

How do ions dissolve in water

Waters partial charges interact with ions forming hydration shells around them

What does not dissolve in water

Non polar substances (lipids)

Key properties of water

High specific heat capacity, high latent heat of vaporisation, cohesion, adhesion, high surface tension, maximum density at 4 degrees, incompressible

High specific heat capacity (Why and importance)

Many H-bonds absorb energy before temperature rises. Habitat temperature stable

High latent heat of vaporisation (Why and importance)

H-bonds need lots of energy to break on evaporation. Effective cooling

Cohesion (Why and importance)

H-bonds pull water molecules together. Allow movement of water up the xylem

Adhesion (Why and importance)

Attraction between water and other polar surfaces. Helps capillary movement in narrow vessels in plants

High surface tension (Why and importance)

Cohesion at the surface exceeds attraction to air. Supports organisms living on the water surface

Maximum density at 4 degrees (Why and importance)

H-bonds space molecular further apart on freezing. Ice layer allows aquatic life to survive winter

Incompressible (Why and importance)

H-bonds weak enough to allow flow. Assists hydraulic mechanisms