Edexcel A-level Biology Topic 1 -
Properties of water
Describe the property: adhesion - ANS - - water molecules attracted to different polar
substances e.g. ions
\Describe the property: cohesion - ANS - - water molecules are polar due to the delta
negative oxygen atom and delta positive hydrogen atoms
- this polarity allows water molecules to form hydrogen bonds, meaning they stick
together
\Describe the property: high specific heat capacity - ANS - Takes a lot of energy to
change the temperature of the water due to the hydrogen bonding
Takes a lot of energy for water to evaporate and chemical reactions can occur at the
optimum temperature
\Describe the property: polar solvent - ANS - - Water is a polar molecule due to the delta
negative oxygen and delta positive hydrogen atoms
- ions/charged molecules can form hydrogen bonds with water
- ionic substances can dissolve in water
\Importance of adhesion - ANS - - allows water to move up a plant in the xylem
- allows polar substances to dissolve in water
- allows for capillary action (water molecules adhere to the sides of a tube which allows it
to move against gravity)
\Importance of water as a polar solvent - ANS - Chemical reactions in cells can take place
in aqueous solutions
\Importance of water having a high boiling point - ANS - Temperatures of large bodies of
water such as lakes and ponds (habitats for aquatic species) do not change much
throughout the year making them good habitats for living organisms
\What are the properties of water? - ANS - - cohesion and adhesion
- high surface tension
- high specific heat capacity
- polar solvent
- less dense when solid
\What is the importance of cohesion? - ANS - - allows water to move up the xylem in
transpiration
- allows the transport molecules in plants and animals
- gives water a high surface tension
\Why does water have a high melting and boiling point? - ANS - - Water is a polar
molecule due to the delta negative oxygen and delta positive hydrogen atoms
- water forms hydrogen bonds
- Hydrogen bonds take a lot of energy to break
\Why is water a liquid at room temperature whereas CO2 and O2 are gases at room
temperature? - ANS - - water molecules are polar whereas CO2 and O2 are non polar
Properties of water
Describe the property: adhesion - ANS - - water molecules attracted to different polar
substances e.g. ions
\Describe the property: cohesion - ANS - - water molecules are polar due to the delta
negative oxygen atom and delta positive hydrogen atoms
- this polarity allows water molecules to form hydrogen bonds, meaning they stick
together
\Describe the property: high specific heat capacity - ANS - Takes a lot of energy to
change the temperature of the water due to the hydrogen bonding
Takes a lot of energy for water to evaporate and chemical reactions can occur at the
optimum temperature
\Describe the property: polar solvent - ANS - - Water is a polar molecule due to the delta
negative oxygen and delta positive hydrogen atoms
- ions/charged molecules can form hydrogen bonds with water
- ionic substances can dissolve in water
\Importance of adhesion - ANS - - allows water to move up a plant in the xylem
- allows polar substances to dissolve in water
- allows for capillary action (water molecules adhere to the sides of a tube which allows it
to move against gravity)
\Importance of water as a polar solvent - ANS - Chemical reactions in cells can take place
in aqueous solutions
\Importance of water having a high boiling point - ANS - Temperatures of large bodies of
water such as lakes and ponds (habitats for aquatic species) do not change much
throughout the year making them good habitats for living organisms
\What are the properties of water? - ANS - - cohesion and adhesion
- high surface tension
- high specific heat capacity
- polar solvent
- less dense when solid
\What is the importance of cohesion? - ANS - - allows water to move up the xylem in
transpiration
- allows the transport molecules in plants and animals
- gives water a high surface tension
\Why does water have a high melting and boiling point? - ANS - - Water is a polar
molecule due to the delta negative oxygen and delta positive hydrogen atoms
- water forms hydrogen bonds
- Hydrogen bonds take a lot of energy to break
\Why is water a liquid at room temperature whereas CO2 and O2 are gases at room
temperature? - ANS - - water molecules are polar whereas CO2 and O2 are non polar
