3.2 Water Flashcards
Why is water a polar molecule
The oxygen is slightly negative and the hydrogens are slightly positive
What are the properties of water
High heat specific capacity (have to put in a large amount of energy to change the temperature)
Doesn’t change rapidly so can be a habitat for aquatic animals
High latent heat of vaporisation (takes a long time to evaporate)
What are hydrogen bonds and how are they formed
Polar molecules including water interact with each other as the positive and negative regions attract each other and form hydrogen bonds.
These are relatively weak interactions which break and reform with others.
Hydrogen bonds occur in high numbers and gives water its unique characteristics.
What are the characteristics of water
Has a high boiling point.
Liquid at room temperature.
Takes a lot of energy to change its state.
When in ice form it’s less dense than in liquid form; because of hydrogen bonds formed.
As water is cooled below 4 degrees C, the H bonds fix the positions of the polar molecules slightly further apart than they would be in liquid state. Produces a giant, rigid but open structure, with every oxygen atom at the centre of the arrangement of hydrogen atoms; resulting in less dense ice which floats.
Cohesive properties and moves as one mass; because of this plants can take up water through the roots.
Also adhesive properties where water molecules are attracted to other materials.
Water is more cohesive to each other than they are to air so water has a surface
Tension.
Why is water essential for life
Essential for life:
Because it’s polar, it acts as a solvent in which many solutes in an organism can dissolve.
The cytosol of prokaryotes and eukaryotes is mainly water.
Other polar molecules: amino acids, proteins, nuclei acids, and other solutes.
Efficient transport system because of cohesion and adhesion.
Cohesion and adhesion acting together makes CAPILLARY ACTION; process where water is taken up a narrow tube against gravity (plants or straws).
Water acts as a coolant which helps to buffer temp. changes because of the large amounts of energy needed to change waters’ temp.
Keeping a constant temp. is good for enzyme action.
In cold environments, ice on the top of water acts as an insulating layer allowing aquatic creatures to survive in the water and on the ice because it floats.
