Water Flashcards
Property of water: reactant.
Give its significance.
Water participates in hydrolysis reactions and is a reactant in photosynthesis.
Property of water: transparent.
Give its significance.
The small particle size makes water transparent.
Transparency allows aquatic organisms to hunt using sight and allows light to penetrate through for photosynthesis to occur.
Property of water: solvent.
Give its significance.
Water is a polar molecule and will dissolve other polar charged molecules and ions by surrounding them and separating them.
Significant bc all metabolic reactions take place in water.
Also substances are transported in aqueous solutions.
Property of water: liquid.
Give its significance.
Water is liquid at room temperature and normal pressures due to hydrogen bonds between the water molecules. It takes a lot of energy to break the bonds thus to separate water molecules.
Significance: use as a transport medium in plants and animals.
Property of water: density.
Give its significance.
In ice, water molecules form a lattice held together by hydrogen bonds. This means that water molecules are held closest together at 4*C and this is therefore when water is most dense.
Significance: when water freezes, the ice formed is less dense and therefore floats on the water’s surface. This insulates the water beneath from further heat loss, so large bodies of waters eg lakes are less likely to freeze, killing aquatic life.
Floating ice packs provide an environment for some organisms eg polar bears.
Water also provides upthrust to support aquatic organisms eg whales.
Property of water: thermal stability.
Give its significance.
A lot of energy is required to break the hydrogen bonds between water molecules and raise the temperature of the water or change liquid water into a gas. Energy is also released when hydrogen bonds form.
Significance: temperatures of large bodies of water eg the ocean are maintained so that they can provide a stable environment.
Easier for organisms (which contain 70 - 90% water) to maintain a stable body temperature for enzyme activity.
Property of water: cohesion.
Give its significance.
Water molecules form hydrogen bonds with each other and tend to stick together.
Significance: cohesion creates surface tension which can support small organisms on the surface of water.
Also cohesion allows water to form continuous vessels of water, which is important in xylem vessels in plants.
Define heat capacity.
The heat required to raise the temperature of liquid by 1*C
