2.4 Water Flashcards
What is the dipolar water molecule?
Two hydrogen and one oxygen molecule. The water molecule has both positive and negative poles making it dipolar.
What are the bonds in water?
Hydrogen Bonds
Fairly weak bonds
Different poles attract to the other poles
Describe Specific heat capacity of water.
It takes more energy to separate the water molecules.
Boiling point of water is higher than expected.
Without hydrogen bonds, water would be a vapour.
Takes more energy to heat a mass of water because water acts as a buffer against sudden temperature changes.
Describe Latent heat of vaporisation.
Hydrogen bonding means it requires a lot more energy to evaporate 1 gram of water.
Sweating is an effective way of cooling the body temperature.
Describe Cohesion and Surface tension in water.
Cohesion - Tendency of molecules sticking together.
Hydrogen bonding allows for water to have large cohesion forces so this is why it can be pulled up a tube.
Surface Tension - The property of the surface of a liquid that allows it to resist an external force.
What is the importance of water in living organisms?
Mammals are typically 65% of water.
For Metabolism and a Solvent.
What is the importance of water in metabolism?
Used to break down many complex molecules through hydrolysis.
Chemical reactions happen in aqueous mediums.
Major material in photosynthesis.
What is the importance of water as a Solvent?
Water readily dissolves other substances:
Gases
Waste
Inorganic ions and small hydrophilic molecules
Enzymes
What are the other important features of Water?
Evaporation cools down organisms (temperature control)
Not easily compressed and provides support.
Transparent and therefore aquatic plants can photosynthesise.
What are Inorganic Ions?
Found in organisms where they occur in the cytoplasm and in other body fluids.
In high or low concentrations.
They perform a large range of functions.
