3.1.7 water Flashcards
electronic structure of water
2 atoms of hydrogen each share single electron with oxygen H2O
2 covalent bonds form
polar molecule
water = dipole
what is specific heat capacity?
amount of energy needed to raise the temperature of 1kg of substances by 1c
high specific heat capacity = thermal stability
high boiling point because of hydrogen bonding = WITHOUT HYDROGEN WATER WOULD BE A GAS AT ROOM TEMPERATURE
takes a lot of energy to heat a body of water
aquatic environments have a stable environment
what is latent heat of vaporisation?
the heat absorbed when a substance changes phase from liquid to gas
high latent of vaporisation = helps cooling
hydrogen bonding = lot of energy for water to evaporate
evaporation of sweat is an affective way for cooling
what is the relationship between cohesion and surface tension?
cohesion between water molecules as a result of hydrogen bonding allows it to be pulled through
cohesion on the surfce of ponds etc acts like a skin and creates surface tension
- supports small organisms like pond skates
water as a solvent
solvent = things dissolving in water
eg
- gases = oxygen and carbon dioxide
- enzymes = chemical reactions taking place in aqueous medium (water)
- waste = ammonia and urea
- inorganic ions and small hydrophillic molecules = monosaccharides and amino acids
water for support
not easily compressed
has a turgor pressure which is supportive for plants
hydrostatic skeleton of intvertabrates eg earthworms
found in many cold blooded organisms that consist of a fluid filled cavity (coelom) surrounded by muscles
pressure of fluid and surrounding muscles are used to change an organisms shape and produce movement eg swimming
water in metabolism
hydrolosis = addition of water to break a bond
condensation = formation of a bond with loss of water
raw material in photosynthesis (photolysis)
non cyclic photo phosphorylation graph in notes
Why is water transparent?
allows aquatic organisms to photosynthesise
allows light to pass to our retina
