water

• Melting point 


  the temperature at which a substance changes from solid to liquid

  water- 0*C

  methane- -182*C
• Specific heat capacity 


  The energy required to raise 1g of a substance by 1*C

  water- 4.2j per g per *C

  methane- 2.2j per g per *C
• Latent heat of vaporisation 


  The energy required for a certain mass of a substance to undergo a phase change

  water-2257j/g

  methane 760j/g
• Boiling point 


  The temperature at which a stubstance changes from a liquid to a gas

  water-100*C

  methane- -160*C
• Water property 1 - cohesion 


  def- the ability of water to form hydrogen bonds with itself because it is polar

  application- helps to maintain the transpiration stream

  - allows some insects to walk on the surface of water
• Water property 2- adhesion 


  Def- water forming hydrogen bonds between itself and a neighbouring surface

  application to maintain the transpirational stream
• water property 3- blood plasma 


  def- water as a polar solvent transport medium

  application- blood plasma transporting glucose for respiration and amino acids for protein synthesis
• Water property 4- water has a high specific heat capacity 


  application- helps to create stable biological environments in terms of temperature

  • homeostasis and enzyme connectics
  • stable ecosystem
• Water property 5- water has a high latent heat of vaporisation


  Application- water/ sweat acts as a coolant to regulate body temperature

  homeostasis/thermoregulation
• Water property 6- water is clear 


  So organisms can hunt

  so photosynthetic organisms can photosynthesise
• What is polarity?

  oxygen draws the electrons from hydrogen closer to the oxygen end resulting in a disproportional distribution of charge meaning water is polar