Water Flashcards
What is the bond that links two water molecules together?
Hydrogen bond
Define the term polar
Electrons are not shared equally over a covalent bond and the atoms have small partial charges as a result of this
What is a dipole?
The partial charges on atoms in a covalent bond
What is electronegativity?
A measure of an atom’s ability to attract shared electrons to itself
Why does the polar nature of water mean it is a solvent?
Positive and negative ends of water molecules are attracted to ions, allowing them to dissolve
Why does the polar nature of water mean it is a transport medium?
It can form hydrogen bonds with other polar molecules or charged ionic compound
Why does the polar nature of water mean it is a coolant?
Water forms many hydrogen bonds which take a lot energy to break
Why does the polar nature of water mean it is a reactant?
Allows it to form many covalent bonds with substances
How does water having a high specific heat capacity make it support life?
Stable environment for aquatic organisms
Thermoregulation
Stable temperature for enzyme controlled reactions
Cells less prone to damage
Why does water having a high latent heat of vapourisation make it support life?
Makes it a coolant - so it stays liquid over a range of temps so it is a stable environment for aquatic organisms
Why does water being cohesive make it support life?
Allows for the transpiration stream?
Surface tension - provides habitiat on surface of water for organisms such as pond skaters
Why does water being a universal solvent make it support life?
Transport medium
Hydrolysis reactant
Reaction medium
Main component of cells as solutes tend to be polar/charged
Why does water being adhesive make it support life?
Allows for transpiration due to attraction to xylem wall
Why does water being a low density solid make it support life?
Ice floats on water creating a habitat on top for terrestrial organisms and insulates water below from cold air providing a habitat for aqueous organisms
Water is most dense at 4C so when it sinks it creates circulating nutrient currents
Define hydrophilic
Polar molecule that is attracted to water molecules and tends to be dissolved by water
Define hydrophobic
Non-polar molecule that is not attracted to water molecules and does not dissolve in water
Define cohesion
Attraction to molecules of the same kind
What is adhesion?
Attraction to other substances
What are the ‘other’ properties of water that are not due to its polar nature?
Helps in sexual reproduction - sperm swim within water for external fertilisation and semen made of water otherwise
Support - makes plant cells turgid so supports them, hydrostatic skeleton in some living organisms
Lubricant - helps bones to move over each other without damage
Why is water a polar molecule?
It has an unequal sharing of electrons because the electrons are more attracted to oxygen as it has more protons
Which part of a water molecule is delta negative and which part is delta positive?
Delta negative - oxygen
Delta positive - hydrogens
How do hydrogen bonds form between water molecules?
Adjacent water molecules align themselves to be attracted to the molecule next to them as they turn their oxygen sides away from each other
What is the bond that holds oxygen and hydrogen atoms together within a water molecule?
Polar covalent bond
