Water Flashcards
What is the structure of water?
two hydrogen atoms and one oxygen atom covalently bonded together
what type of molecule is water?
it is a dipolar molecule
what does dipolar mean?
pair of equal and opposite electric charges
what is hydrogen bonding?
electrostatic forces of attraction between positive pole of a water molecule with negative pole of another
name properties and uses of water
- temperature control:
- specific heat capacity
- latent heat of vaporisation
- cohesion - transport
- solvent
- surface tension - support
- metabolite
what is specific heat capacity?
energy required to raise the temperature of 1g of a substance by 1 degree Celsius
does water have high or low specific heat capacity?
high
- absorbs lots of heat before temperature changes
why is the property of specific heat capacity important in animals?
- water acts as a buffer to sudden temperature changes
give another reason why animals can survive at bottom of pond when covered in ice
- ice is an insulator
- less dense than water because particles held further apart in lattice so can float on top
- prevents heat loss
what is latent heat of vaporisation?
heat energy required to transform water to a vapour
does water have high or low latent heat of vaporisation?
high
- lots of heat needed to change water into vapour
what do mammals produce to release heat?
produce sweat
- evaporation of sweat cools body by taking heat away from body
what is cohesion?
tendency of molecules to stick together
why is water cohesive?
due to hydrogen bonding - attraction of poles - flow as one unit
why is cohesion a useful property of water?
- useful for transport
- allows water to be drawn up by xylem vessels
