water Flashcards
what bond holds water molecules together? [1]
hydrogen
what are the properties of water? [4]
solvent, transport medium, coolant, habitat
why is water a good solvent? [2]
-molecules are polar
-polarity enables molecules to attract solute molecules
how can hydrogen and sodium ions help cut flowers last longer? [2]
hydrogen:
regulate pH
sodium:
regulate water potential
how can properties relating to density of water contribute to survival of organisms? [3]
-ice is less dense than water, it floats
-ice provides a habitat
-ice insulates the water below = animals can move
what properties of water make it an ideal habitat for an amphibian? [2]
-high specific heat capacity, for temp stability
-good solvent
describe the formation of a hydrogen bond between 2 water molecules, explain why water can form these bonds. [3]
-between oxygen and hydrogen molecules
-between electropositive δ+ and electronegative δ− molecules
-water molecule is polar
why is waters ability to act as a solvent important for the survival of organisms? [3]
-medium for metabolic reactions
-able to dilute toxic substances
-transport medium, eg xylem + phloem
physical properties arise from hydrogen bonds:
describe ways which physical properties of water allow organisms to survive in a range of temps. [8]
[1]ice is less dense than water so it floats
[2]ice is a habitat for organisms eg polar bears
[3]ice keeps water insulated
[4]organisms don’t freeze
[5]high specifc heat capacity, large amount of enegrry needed to change temperature
[6]thermally stable environment for aquatic organisms
[7]high latent heat of vaporisation, large amount of energy to change from liquid to a gas
[8]evaporation is an efficient cooling mechanism eg sweating
define hydrolysis [1].
reaction that occurs when water is added to break apart a bond in a molecule
define hydrophilic [1].
phosphate group of a phospholipid that readily attracts water molecules
explain what polarity means in reference to the structure of water.
- regions of negativity and positivity
O=slightly negative
H=slightly positive
why can water molecules interact with eachother?
polar molecules-positive and negative regions attract each other forming hydrogen bonds which are weak, they break and reform constantly between moving water molecules .
what’s the name for waters moving as one mass property, what does it allow?
cohesion-molecules are attracted to eachother
plants can draw water up roots
define solvent.
why is water a good solvent?
solutes can be dissolved
because polar it’s attracted to opposite regions, can dissolve positive or negative ion by surrounding it
