1
Q
hydrogen bond
(intermolecular force)
A
- formed between 2 water molecules
- between oxygen and hydrogen
2
Q
why hydrogen bonding occurs
A
- water is polar
- oxygen can attract more electrons than hydrogen making is more negative
- oxygen is delta negative
- hydrogen delta positive
-delta negative oxygen will attract with delta positive hydrogen
3
Q
is hydrogen bonding strong?
A
-strongest intermolecular force but weak compared to covalent bonding
4
Q
properties of water:
A
- High specific heat capacity
- High latent heat of evaporation
- Cohesive
- Solvent
- Ice
- Liquid
5
Q
is water useful in metabolic processes?
A
yes!!!
6
Q
High specific heat capacity
A
- Energy required to raise the temperature of 1 gram of a substance by 1°C (very high)
- hydrogen bonds between water molecules can absorb lots of energy
- lots of energy is required to make molecules vibrate
7
Q
High latent heat of evaporation
A
- the amount of energy required to get a substance from one phase liquid to another gas
- hydrogen bonds are very stable and require lots of energy to break
8
Q
Cohesive
A
-water molecules attract each other because of hydrogen bonding
and can stick to each other
- helps water to flow because all water molecules are sticking together and will pull each other along
- makes water a good transport medium
9
Q
solvent
A
- since water is polar, it can interact with the slight positive and negative charges in an ionic compound
- ions break apart and dissolve in water and water molecules will go around them
- useful for transporting ions
10
Q
ionic compounds
A
-compounds with one positive ion and one negative ion
11
Q
what is a solvent?
A
-things can dissolve in it particularly ionic compounds
12
Q
Ice
A
- molecules spread out due to hydrogen bonds
- not as close together as they would be in liquid
- this makes water less dense in a solid state due to the lattice structure
- this causes ice to float and form an insulating layer for the water underneath which won’t freeze
- this means organisms will stay alive in the water underneath
- aquatic organisms can survive in cold environments
13
Q
metabolism
A
reactant:
- hydrolysis
- photosynthesis
product:
- condensation
- respiration
14
Q
Density of water
A
- Molecules spread out
- lattice
- insulating layer
- water below doesn’t freeze
- organisms don’t freeze
- can still move
- currents allow flow of nutrients
15
Q
solubility of water
A
- ions are polar
- interact with water
- organisms uptake minerals
- e.g. nitrates help create amino acids
16
Q
temperature of water
A
- stable hydrogen bonds
- energy to break bonds
- high specific heat capacity
- Many hydrogen bonds
- small variation in temperature
- Enzymes work
- gases remain soluble
as biology module 2
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