Water Flashcards
Why is water described as dipolar?
The hydrogen atoms have a slightly positive charge, whereas the oxygen atom has a slightly negative charge, meaning it has both positive and negative poles, so is dipolar
What is the specific heat capacity of water like?
High SHC - water molecules stick together, so it takes more energy to separate them. This means that water has a high boiling point and acts as a buffer to sudden temperature variations
What is the latent heat of vaporisation of water like?
Large - hydrogen bonding between water molecules means that it takes a lot of energy to evaporate 1 gram of water, providing a cooling effect with little loss of water through evaporation
What is the cohesion of water like?
High cohesion due to hydrogen bonding - this allows water to be pulled up through a tube, such as xylem vessels in plants and produces surface tension where water meets air
How is water used in metabolism?
- used to break down many complex molecules by hydrolysis, and is produced in condensation reactions
- used in photosynthesis
- chemical reactions in water
How is water used as a solvent?
Water readily dissolves other substances eg. gases such as oxygen, waste such as urea, inorganic ions such as amino acids, and enzymes whose reactions take place in solution
What properties of water make it important to organisms?
- metabolite in condensation/hydrolysis/respiration
- solvent so can transport substances
- high SHC so buffers temp change
- large latent heat of vaporisation - cooling effect through evaporation
- cohesion so supports columns of water and surface tension
