Water 2.1.2 (a) Flashcards
Why is water polar?
Water contains Hydrogen and Oxygen. Oxygen has a greater electronegativity than Hydrogen.
- makes Oxygen delta negative
- attracts electrons more - makes Hydrogen delta positive
- attracts electrons less
Molecules with different regions of electronegativity are polar.
How does Hydrogen Bonding work?
The delta negative charge of Oxygen and delta positive charge of Hydrogen attracts each other.
So Hydrogens in other water molecules will interact with Oxygens in other water molecules and form a hydrogen bond.
Are Hydrogen Bonds strong or weak?
They are very weak…
Why cant non-polar molecules dissolve in water?
As there is no overall electronegativity in non-polar molecules, they cannot be attracted by water molecules which means that they cannot be dissolved.
What are the two main properties of water?
Water is COHESIVE
and
Water is ADHESIVE
why is being cohesive helpful for water?
it moves up as ONE MASS as the molecules are attracted to eachother
why is being adhesive helpful for water?
water molecules are attracted to other materials due to their polarity
they push outwards
What is capillary action?
Movement of water upwards
This occurs in the xylem of a plant
- the water molecules stick together due to cohesion
- the water molecules can stick to the side of the tube due to adhesion
What are other properties of water?
has a high specific heat capacity
has a high latent heat of evaporation
very cohesive
lower density when solid
so ICE forms
a good solvent
surface tension
high latent heat of evaporation
takes a lot of energy to break hydrogen bonds so less likely to turn into gas
CONSTANT HABITAT
very cohesive
with water being polar, it attracts other water molecules
CAPILLARY ACTION
high specific heat capacity
hydrogen bonding means water needs a lot of energy to increase it’s temperature
CONSTANT HABITAT
lower density when solid
in ice water molecules are held further apart which means an open lattice is formed
allows ice to float on water
PROVIDES A HABITAT
good solvent
as water is polar, it is attracted to other polar molecules
allows for ions to dissolve
GOOD TRANSPORT MEDIUM
What does water provide for living organisms?
Water acts as a coolant
Water provides a constant habitat
- it’s specific heat capacity is very high which means it is very hard for water’s temperature to change
- it’s latent heat of fusion is very high which means it is very hard for water to evaporate
- ice forming on top of water provides insulation for animals below it
- due to surface tension animals can live on top of lakes and ponds
- solubility allows for ions to dissolve in water in the blood
