Properties of Water

Water is the principal solvent in organisms

  • Water is a polar solvent, so polar compounds will dissolve (and sometimes dissociate) and ionic compounds will dissociate in water

  • Covalent compounds (hydrophobic) will not dissolve

Hydrogen bonding makes water cohesive and adhesive

  • Attractive forces between water molecules is called cohesion.
  • Attractive forces between water molecules and other substances is called adhesion.

These forces account a number of properties for water:

1) Meniscus, when it is in a relatively narrow chamber:

Drawing

Photograph

          2) Very high specific heat;

Water helps maintain a stable temperature

  • Because of hydrogen bonds, water has a relatively high boiling point, relatively low freezing point, and extremely high specific heat, i.e., the amount of heat required to raise the temperature of 1 gram of water 1 degree Celsius.
  • Also because of hydrogen bonds, the density of ice is less than that of liquid water, so ice floats.

Water molecules will dissociate into H+ ions and OH- ions

  • Normal concentration of each of 10-7 M.
  • pH is defined as - log10[H+]
  • When a source of H+ ions is added to a solution, the dissociation reaction is driven to reduce the concentration of OH- ions, so that the value of pH will decrease.
  • When a source of OH- ions is added to a solution, the dissociation reaction is driven to reduce the concentration of H+ ions, so that the value of pH will increase.

 

Buffers minimize pH change

  • Adding a weak acid and its salt to water will increase the capacity of that solution to absorb H+ ions without significantly changing the pH.
  • Buffers are crucial in the functioning of living organisms.

 

Symptoms of Acidosis depend on cause (Metabolic, respiratory, alcoholic, diabetic)  (Lesson to write home about:  Acidosis is very bad.)

·                        Nausea

·                        Weakness

·                        Rapid breathing

·                        Confusion or lethargy may also occur.

·                        Confusion

·                        Easy fatigue

·                        Lethargy

·                        Shortness of breath

·                        Sleepiness

 

Symptoms of Alkalosis (Lesson to write home about:  Alkalosis is very bad.)

  • Confusion (can progress to stupor or coma)
  • Hand tremor
  • Light-headedness
  • Muscle twitching
  • Nausea, vomiting
  • Numbness or tingling in the face or extremities
  • Prolonged muscle spasms (tetany)