A1.1 Water Flashcards
Define cohesion
Hydrogen bonds hold water together- Cohesion among water molecules plays a key role in the transport of water and dissolved nutrients against gravity in plants.
Special properties of water.
Cohesion, Adhesion, Buoyancy, Viscosity, Thermal conductivity, Specific heat capacity, useful as a solvent.
Define adhesion
The force by which individual molecules stick to surrounding materials and surfaces.
How are hydrogen bonds drawn?
Dashed lines
Define hydrogen bond
A type of weak attractive intermolecular force; a hydrogen atom in a molecule is attracted to an electronegative atom, such as oxygen, in a different molecule.
What is water?
Water is the medium of life.
Define covalent bond
A bond formed by the sharing of electrons between atoms
Define hydrophilic
Attracted to water. Polar substances that are attracted by water. Have an affinity for water and are soluble in water.
What allows plant roots to draw up water?
Adhesion forces
Describe how the black-throated loon (Gavia arctica) interacts with the physical properties of water in their habitat.
Buoyancy in water allows the bird to stay afloat without expending a lot of energy, however when flying through air the bird must expend energy to stay aloft. Air is not viscous, so the loon can easily move through it when flying. The loon doesn’t lose as much body heat to the air because air has low thermal conductivity. However, because the air has a low specific heat, its temperature changes as rapidly.
Define hydrophobic
Non-polar substances that are repelled by water. They lack affinity for water and are insoluble in water.
What are substances that like water called?
Hydrophilic.
What are substances that don’t like water called?
Hydrophobic.
Define solvent
A liquid in which another substance can be dissolved.
Is water essential to life and why?
Yes. It serves a s a medium for metabolic reactions.
What properties of water allows it to be used as a medium of life?
Water has high buoyancy and high heat capacity.
Define solute
Dissolved molecule or ion in a solution
Describe how the ringed seal (Pusa hispida) interacts with the physical properties of water in their habitat.
Buoyancy in water allows the seal to stay afloat without expending a lot of energy. However, the water is viscous, so the seal has adaptations for streamlining as it swims through it. Water has a greater thermal conductivity than air, so the seal needs to insulate itself with blubber to maintain body temperatures. However, because the water has a high specific heat, the temperature of the water does not change as rapidly as the air around it, providing habitat stability for the seal.
State two reasons why water was retained on early Earth.
- The distance of the Earth from the Sun keeps temperature on Earth below that needed to vaporize water.
- Earth’s gravity keeps water from escaping the planet.
