3.1.7 Water Flashcards
2 properties of water
Dipolar structure
Hydrogen bonding
What’s a polar molecule
E.g
Molecules with 2 different poles that behave differently
E.g phospholipids
Why is water dipolar
Oxygen has a small negative charge
Hydrogens have a small positive charge
Overall what net charge does water have
None
What’s a hydrogen bond
The opposite charges between water molecules attracting (positive Pole of 1 water molecule will attract to the negative Pole of another)
Why do water molecule tend to stick together
As although hydrogen bonds are weak there are many of them
3 properties that hydrogen bond sticking together gives water
Specific heat capacity
Latent heat of vaporisation
Cohesion + surface tension
Why is water boiling point high
As more energy is required to break water molecules apart as they stick together
What does water act as again temperature changes
What’s this important in (2)
A buffer
Aquatic/marine ecosystems
Inside organisms
Why does water require a lot of energy to make it evaporate
Due to the hydrogen bonds
What’s latent heat of vaporisation
Amount of energy required to evaporate 1g of water
Why is water evaporation important
Helps mammals cool down in high temperatures (sweat)
What’s cohesion
Water molecules sticking together
How do water molecules move due to cohesion
As a column
When is cohesion important
When plants move water up their stems in the xylem
What happens to water molecules when they meet air
What’s this called
They are pulled back towards the other water molecules rather than escaping into the atmosphere
Surface tension
Why can small insects move across water surfaces
Due to surface tension
5 reasons why water is so important
Makes up things Solvent Transparent Metabolism Evaporation
2 things water makes up
98% jellyfish
65% mammals
What does water provide for species to live in
A rich ecosystem
2 examples of when water is a solvent
How is this useful
Gases dissolve in wiser
Inorganic ions dissolve in water
Waste products dissolve in water
So can be transported
Why is it useful that water is transparent
E.g
So aquatic plants can photosynthesise
E.g pondweed
What does water provide for metabolism
The fluid environment for chemical reactions to occur in
How is water involved with large molecules
What the process called
Breaking them up
Hydrolysis
