Water + Inorganic Ions Flashcards
What is electro-negativity?
The measure of an atoms pull on a bonded pair of electrons
Why are water molecules dipolar?
The bonded pairs of electrons are slightly more attracted to the positive nucleus of oxygen so the hydrogen end is slightly positive
What type of bonding occurs in water molecules
Covalent bonds
What bonding occurs between water molecules?
Hydrogen bonds
Name all the properties of water
- Cohesion
- Adhesion
- Transparent
- High specific latent heat of vaporisation
- High specific heat capacity
- Metabolite
- Solvent
- Ice is less dense than water
Why are water molecules cohesive?
Water molecules are cohesive due to the hydrogen bonds between the molecules.
The slightly negative oxygen end is attracted to the slightly positive hydrogen end of another water molecule
How does cohesion aid living organisms?
Cohesion creates surface tension which supports small organisms like pond skaters on the surface
Cohesion between molecules helps support continuous columns of water in the xylem (transpiration stream).
How does adhesion aid living organisms?
Adhesion occurs between water and another polar substance
Capillary action, due to adhesion between the water molecules and the walls of a plant vessels, also facilitates the movement of water up the stem of a plant.
How does transparency of water aid living organisms?
It allows light to penetrate which means aquatic plants can photosynthesise
Why is water a good solvent?
Water is a polar molecule which makes it a universal solvent. This means ionic and other polar molecules can dissolve in it for transportation, e.g salt or amino acids.
Also chemical reactions occur more quickly in solution.
How does the property of being a metabolite make water useful?
It allows for hydrolysis and condensation reactions e.g in ATP
Why does ice float on water?
When water freezes, it expands as the hydrogen bonds hold the water molecules further apart. Therefore making it less dense than water so it floats
Why is ice floating a useful property?
It prevents freezing of water below and provides a habitat for aquatic organisms to survive
Why does water have a high latent heat of vaporisation?
A lot of energy is required to break the hydrogen bonds between the water molecule.
Why is high latent heat of vaporisation useful?
It acts as a thermal regulatory mechanism for organisms.
For example, when we sweat, lots of our heat energy is released when it is used to evaporate the water which helps provide a cooling effect.
