WATER Flashcards
What is cohesion
The attraction of like molecules to one another e.g. like molecules are the water molecules in the water drops
What is surface tension
Describes the cohesion between water molecules
What are hydrogen bonds
Formed by the hydrogen atoms of one molecule being attracted to the oxygen atoms on another molecule
What is the transpiration stream
Water moves up the xylem vessels as a continuous column due to cohesion tension. This allows water to move from the roots to the top of the tallest trees
Why does water have these properties
Because molecules are polar
What is a polar bond
A covalent bond between two atoms where the electrons forming the bond are unequally distributed
This causes the molecule to have a slight electrical dipole where one end is slightly positive and the other is slightly negative
Where can hydrogen molecules form
Between water molecules (cohesion)
Between water molecules and other surfaces (adhesion)
Why is the sand hotter than the water
Water has a higher specific heat capacity
What is specific heat capacity
The amount of energy required to increase waters temperature by 1°C
Water = 4.2kJ/kg/K
Energy needed because of the strong cohesive bonds in water molecules require energy to break them apart
What is latent heat of fusion
Temperature remains constant as solid turns to a liquid
What is latent heat of vaporisation
Temperature remains constant as liquid turns to gas
Importance of latent heat capacity to living organisms
Animals that are able to sweat can keep cool as the water in sweat evaporates off the surface of the animal
Plants are cooled when water evaporates from their leaves via transpiration
Why is water a good solvent
Water is a good solvent for many substances found in living things
Because water is polar it is attracted to any other substance that is also polar
The positive and negative regions of the water molecules are attracted to the negative and positive regions of the solute molecules or ions
When can metabollic reactions occur
When the reactants are dissolved in water
Allows substances to be transported
What is a metabolite
Water molecules can also be involved in chemical reactions directly
E.g. condensation and hydrolysis
