1.7 Water Flashcards
Is water polar
Yes
Which part of a water molecule has a higher affinity for electrons
the oxygen
Which atom in a water molecule is delta plus
the hydrogen
Which atom in a water molecule is delta negative
oxygen
What type of bond bonds the hydrogen to oxygen in a water molecule
a covalent bond
Is water a dipolar molecule
yes
What creates the cohesion in a water
the hydrogen bonds between the water molecules (NOT THE ATOMS)
Are hydrogen bonds weak or strong
Individually weak but together they are considerably strong
What is a hydrogen bond
An attraction between the slightly negative oxygen and slightly positive hydrogen
why is there surface tension in water
because the hydrogen bonds face down because hydrogen bonds can’t bond water with air.
What are the 8 properties of water
- Universal solvent
- High latent heat of evaporation
- High specific heat capacity
- Metabollite
- Ice less dense than water
- Cohesion
- Low viscosity
- Transparent
What property of water is creates this biological importance: Chemical reactions inside cells happen in aqueous solutions; water is also the main transport medium in organisms
Universal solvent
What property of water creates this biological importance: COOLANT: heat is lost from a surface when water evaporates from it, which acts as a cooling mechanism e.g. sweating
High latent heat of evaporation
What property of water creates this biological importance: TEMP STABILISER: cells can absorb/ lose a lot of heat energy, but only show a small temperature changes, organisms can live in extreme climates
High specific heat capacity
What property of water creates this biological importance: Water required in photosynthesis, in condensation reactions to synthesise biological polymers, and in digestion of polymers via hydrolysis
Metabollite
What property of water creates this biological importance: THERMAL INSULATION : Ice floats on water insulating organisms to live below it
Ice less dense than water
What property of water creates this biological importance: TRANSPORT MEDIUM: This means that long chains of water molecules don’t break
Cohesion
What property of water creates this biological importance: Water can flow easily therefore act as a lubricant
Low viscosity
What property of water creates this biological importance: Light can pass through it so underwater plants can photosynthesise
Transparent
Explain how the polarity of the water molecule is created
When the atoms covalent bind the oxygen becomes slightly negative due to it have a higher affinity for the electrons, leaving the hydrogen slightly positive- meaning the water molecule is slightly charged , therefore polar
What are the names of the bonds that attract water molecules together
Hydrogen bonds
Define the term solvent
A liquid that substances can be dissolved in
Give two properties of water that are important in the cytoplasm of cells.
For each property of water, explain its importance in the cytoplasm. ( 4 marks )
- Polar molecule
- Acts as a universal solvent
- Universal solvent
- Metabolic reactions occurs faster in solutions
- Reactive
- Takes place in hydrolysis/ condensation
