Unit 1
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25 Terms
Water Molécule
A polar molecule made of 1 oxygen atom and 2 hydrogen atoms
Polarity
Having positively and negatively charges areas bc of an uneven distribution of electrons
Negative Poles
Areas with more electron, around the oxygen atom
Positive pole
Area with fewer electrons, near the hydrogen atom nuclei
Hydrogen bonds
A weak bond formed between polar water molecules
Why is cohesion High in water?
H-bonds make water molecules stick to each other more strongly. It causes surface tension.
What is waters density lower when frozen (ice)?
The extra h-bonds cause cold water molecules to move apart slightly
Why does water have high specific heat?
Some heat is used to break h-bonds so more is needed to raise the water temp.
Why is water an excellent solvent?
Bc polar water molecules dissolve so many substances.
Why does water have dipolarity?
Bc water molecules contain both positive and negative charges.
Why is water a good coolant in sweat?
Because it has a high specific heat
Why is water good for transport?
It can easily dissolve glucose, sodium chloride, oxygen, and many amino acids.
Why is water a medium for life?
1st cells formed when h20 became enclosed in membrane
Substances can be dissolved within it + chem. Rc happen
It makes up 60% of human life
Transport mat. In and out of cell
Most molecules are dissolved within H2O
Makes up cytoplasm a of cells and internal space of organelles
Provides medium for org, in lakes, rivers, and ponds
How are H2O molecules together?
By polar covalent bonds
What are properties of water?
cohesion
adhesion
Buoyant
Viscous
High specific heat
High thermal conductivity
Why does water molecules have great adhesion?
Other molecules are polar molecules and bond due to the H-bonds
Example of water’s cohesion
Conduction of water under tension in xylem; H20 sucked up from roots through the stems to the leaves in vessels classed xylem tissue
Water surface as a habitat due to surface tension
What is surface tension?
Elastic membrane at the top of bodies of water, which allow organisms to float on the top of the water and that helps them thrive in environment.
Example of water adhesion
Water adheres to chemicals in soil. Capillary actions draw water from soil to roots
Water adheres to cellulose in cell walls, drawing water from xylem to keep cell walls moist.
Benefit of water having high specific heat. Why is it useful?
Water can absorb and give off heat without much change in temperature because of the large amount of energy needed to do so that it doesn’t have.
Moderates temp or earth
And stay at consistent temp even on colder nights
What is thermal conductivity?
The rate at which heat passes through a material.
What is buoyancy?
Density of an object lower than density of water, object will float
How are ringed seals (Pusa Hispida) against the prop. Of water?
Buoyancy- keeps snout above water to breath, however when diving expels water
Viscosity- paddle like feet and streamlined body assist in in moving through water while swimming
Thermal conductivity- minimize heat loss through the use of 10cm thick blubber in skin
How is a black throated loon (Gavin Attica) against the properties of water?
Buoyancy- spends a lot of time at the surface and depend on the buoyancy to stay up
Viscosity- requires energy to overcome viscosity, webbed feet and streamlined body aides this
Thermal conductivity- lose lots of heat to water bc of high TC so they spread the oil form glands at the tail using their beaks to water proof feathers, reducing heat loss.