Water Flashcards
1
Q
describe the polarity of a water molecule
A
- dipolar molecule > has two charged ends
hydrogen is slightly positive
oxygens are slightly negative
2
Q
why is water a good solvent
A
- water is polar
- so it is a good solvent for polar substances
- negatively charged atoms in substances will be attracted to the hydrogen
- positively charged atoms will be attracted to the oxygen
- this means the substance breaks apart
3
Q
which substances can water not dissolve
A
non-polar
e.g. lipids
4
Q
why does water have a high specific heat capacity
A
- it has many hydrogen bonds
- although they are weak, there are lots of them
- the large number of bonds to break requires a lot of energy / heat
- therefore the heat being transferred to water is used up in breaking the bonds first, before the particles can gain kinetic energy
5
Q
what is the advantage to living organisms for water having a high specific heat capacity
A
- living organisms have a high specific heat capacity > due to lots of water within the organisms
- this means that a lot of the heat is absorbed by the water without the temperature of it changing too much
6
Q
why is the high specific heat capacity of water an advantage to aquatic organisms
A
- large bodies of water such as the ocean dont change temperature as quickly or highly as the air
- this provides aquatic organisms with an environment where temp changes are very small and gradual
7
Q
why does water have a high latent heat of vaporisation
A
- water has a lot of hydrogen bonds which take a lot of energy to break
8
Q
why is a high latent heat of vaporisation advantageous to organisms
A
- water provides a cooling effect
- humans sweat > water released onto skin > heat from skins surface is transferred to the water (sweat) to evaporate it
- this removes heat from the organisms and therefore cools it down
9
Q
why does water have cohesion
A
hydrogen bonding between the S- O and S+ H between molecules
10
Q
why is cohesion advantageous to organisms
A
- supports transpiration in plants > continuous column of water
- surface tension in water > provides organisms with a habitat away from predators with the water
11
Q
why is water classed as a metabolite
A
- involved in many reactions such as hydrolysis and condensation etc