3.1.7 Flashcards
Describe the structure of water
Polar molecule- hydrogen atoms have a slight positive charge, oxygen atom has a slight negative charge
Opposite charges attract so H from one water molecule is attracted to O of another
Creates cohesion between molecules
What is the latent heat of vaporisation?
The heat required to turn a liquid at its boiling temperature into a gas at the same temperature
How is water’s latent heat of vaporisation an advantage?
Water molecules are cohesive so relatively difficult to separate- have high latent heat of vaporisation
Therefore take a lot of energy to separate during evaporation
Prevents water loss in plants and aids in cooling in animals through sweating
What is specific heat capacity?
The heat required to raise the temperature of a volume of liquid by one degree
How is water’s specific heat capacity an advantage?
Water has a relatively high heat capacity which means lakes and rivers don’t change temperature much
Means fish have a stable environment
Also helps larger organisms whose bodies mainly consist of water to maintain a stable body temp
Therefore buffers changes in temperature
What is a solvent?
A liquid able to dissolve other substances
How is water used as a solvent?
Water is the solvent in which many biological reactions take place
Wide range of substances are water soluble allowing them to be transported in substances like blood or sap
Water acts as a metabolite in some of these reactions including hydrolysis and condensation reactions
Describe how to cohesion of water is useful
Strong cohesion between water molecules
Supports columns of water in tubes of transport like in plants
Also produces surface tension where water meets air which supports small organisms
What are the bonds between water molecules called?
Hydrogen bonds
What are the bonds between atoms in water called?
Covalent bonds
Explain the significance of water
A metabolite in condensation/ hydrolysis reactions
A solvent so can transport substances
High specific heat capacity so buffers temp changes
Large latent heat of vaporisation so has cooling effect through evaporation
Cohesion supports columns of water in plants and produces surface tension supporting organisms
