Water: Practice Questions

• a.

  Hydrogen bonds between water molecules create surface tension that allows the mammal to sweat without losing essential ions.

• b.

  The high density of water allows it to support the weight of the mammal while swimming in aquatic environments.

• c.

  Water acts as a buffer against rapid internal temperature changes because it requires a lot of energy to raise its temperature by \(1^{\circ}C\).

• d.

  Evaporation of a small amount of water from the skin surface removes a large amount of body heat, providing an effective cooling effect.

• a.

  Strong cohesive forces caused by the small molecular mass of water.

• b.

  Solvent properties due to the ability of water to form ionic bonds with solutes.

• c.

  High latent heat of vaporisation due to the polarity of the oxygen-hydrogen bonds.

• d.

  High specific heat capacity due to the presence of many hydrogen bonds between molecules.

• a.

  High surface tension caused by the evaporation of water at the stomata, which pushes the water column upwards from the roots.

• b.

  Low viscosity caused by the lack of polarity in water molecules, allowing them to slide past one another easily under pressure.

• c.

  Strong cohesion caused by hydrogen bonding between the slightly positive hydrogen of one molecule and the slightly negative oxygen of another.

• d.

  Adhesion caused by covalent bonding between water molecules and the lignin in the cell walls of the xylem vessels.

• a.

  The polar nature of water allows it to act as a universal solvent for salts found in sweat, facilitating evaporation.

• b.

  Water has a high specific heat capacity, meaning it can absorb a lot of thermal energy without its own temperature rising significantly.

• c.

  Strong cohesive forces between water molecules prevent them from evaporating too quickly, prolonging the cooling effect.

• d.

  A large amount of energy is required to break the hydrogen bonds between water molecules to turn liquid water into water vapour.

• a.

  The formation of hydrogen bonds between water molecules, creating high cohesive forces.

• b.

  The ability of water to act as a metabolite in condensation reactions within the tracheids.

• c.

  The relatively high specific heat capacity which prevents density changes in the xylem.

• d.

  The high latent heat of vaporisation which prevents the water column from boiling.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.