water Flashcards
what is water ?
water is a dipolar molecule
- some parts are slightly negatively charges and some parts are slightly positively charged
- water has an unevenly distributed charge
properties of water that make it important for living things :
- it is a metabolite
- it is a solvent
- has a high heat capacity
- has a large latent heat of vaporisation
- has strong cohesive bonds between water molecules
- it is adhesive
metabolite
used in chemical reactions such as condensation , hydrolysis and photosynthesis reactions
solvent
allows solutes to dissolve in it and to be transported in it
- so it allows transpiration o occur
high heat capacity
thermoregulation
- temperature control so that a constant temperature is maintained as the temp of water remains relatively stable
- a lot of energy is required to raise the temperature of water as some of the energy is used to break the hydrogen bonds
- so enzymes do not denature
large latent heat of vaporisation
enables sweat to evaporate off the surface of the skin as it provides a cooling effect
- it means that a lot of energy is required to convert water in its liquid state to a gaseous state as energy is needed to break the hydrogen bonds between water molecules
strong cohesive bonds between water molecules
its sticky so it has large surface tension
it is adhesive
sticks to many surfaces
at temperatures of 0 degrees and below, what does water form ?
water forms a crystalline substance called ice
what does the arrangement of water molecules in ice allow it to have the property of ?
it makes ice less dense than water so ice will form at the surface of a body of water such as a pond or lake
because ice floats to the top of the body of water, what does this help with ?
this insulates the water beneath and thus prevents the whole of the body of water freezing solid so living organisms can survive beneath the ice providing there is sufficient food and oxygen available
what kind of property makes water a useful lubricant ?
its viscosity
what are examples of water being a lubricant ?
- mucus
- synovial fluid
- pleural fluid
- perricardial fluid
- perivisceral fluid
what is the supporting role of water ?
mechanical support
with its large cohesive forces, water molecules lie close together
water is therefore not easily compressed , making it useful min supporting organisms
state the examples of mechanical support of water ?
- hydrostatic skeleton
- turgar pressure
- humours of the eye
