Properties of water Flashcards
Why is water important for living organisms
Metabolic processes,transport and habitat for aquatic organisms → key elements found in aqueous solutions and all reactions of life rely on water
Describe + explain surface tension of water
Highest surface tension of any liquid except for mercury → - molecules in surface aren’t affected by molecules above and so pull together more strongly due to multiple hydrogen bonds = stretched membrane
Purpose of high surface tension in water
Animals can build habitats on water and animals can move across it
Describe the colour of water and its effects
Colourless = transparent → sunlight reaches aquatic plants so they can photosynthesise
Explain density of ice compared to water
Water expands as its freezes so it reduces density as from liquid → solid molecules became in rigid lattice structure = more volume
Effect of density of ice compared towater
Ice is less dense than water so floats on top creating insulating layer preventing water from freezing so aquatic animals can live
Explain SHC of water
Water has high SHC = can absorb large amounts of heat energy before changing temp due to hydrogen bonds → needs a lot of heat energy to raise temp!!!
Effect of SHC on water
High SHC = prevents large fluctuations in temp of water = stable aquatic environment and temp-for animals to live
Explain latent heat of vaporisation of water
Water has high LHV so needs to absorb large amounts of heat energy before changing from liquid → gas due to hydrogen bonds
Explain effect of LHV of water
High LHV = organisms use this to cool down via sweating → excess heat energy used to turn liquid water on skins surface to water vapour and move excess heat away from body
Explain how water is a universal solvent
Water is a polar molecule so other polar and ions will dissolve in it because the slight charges of water will attract the charges of the other molecules + form hydrogen bands so the molecules dissolve → cations + anions attracted to different atoms of water → universal solvent because it can dissolve any polar molecule like glucose + minerals
Explain effect of water being universal solvent/ polar molecule
Animals → solutes can be dissolved in blood plasma and transported around body as its mainly water plants → solutes like nutrients dissolved in water + transferred via xylem vessel cells + phloem cells to where needed in plants
Explain cohesion between water molecules
Hydrogen bonds = weak but multiple = cohesion force → strong attraction so water molecules stick together so water is liquid instead of gas at room temp
Effect of cohesion of water molecules
Helps water to travel up xylem vessel cells in plant in long unbroken columns to transport to leaves
Explain how water is a polar molecule
Oxygen attracts . Shared electron pair closer to nucleus of oxygen atom because they are more electronegative than hydrogen atoms so it has slight negative charge and hydrogen atoms have slight positive charge as electrons move away from them → unequal sharing of electrons across covalent bond. = polar covalent bond
