A1.1 Water

Question 1

Why is water important?

Answer 1

-first cells originated here
-many organisms live in it
-many organisms are composed of water
-cell shape and structure depend on water
-essential for many metabolic reactions

Question 2

What does it mean that water is polar?

Answer 2

-water is covalently bonded
-has a positive end and a negative end because of the unequal sharing of electrons
-has a higher electronegativity, more protons
-can associate with ions and other polar molecules
-the reason it has so many unique properties

Question 3

Water’s hydrogen bonding

Answer 3

-intermolecular association because of polar covalent bonds

Question 4

Water’s adhesion

Answer 4

-attraction to different molecules
-ex: capillary action for water to flow up the xylem
-leads to transpiration

Question 5

Water’s cohesion

Answer 5

-hydrogen bonds hold water together causing surface tension
-water is attracted to water

Question 6

Water as a solvent

Answer 6

-dissolves solute for ions and polar molecules making it a good transport medium
-medium for metabolism by increasing enzymatic collision
-promotes enzymatic action by absorbing heat

Question 7

Water’s high specific heat capacity

Answer 7

-lots of energy is needed to raise the temperature of 1 g of water by 1 degree as hydrogen bonds must break
-high boiling and melting point

Question 8

Why does water have a high heat of fusion and vaporization?

Answer 8

-hydrogen bonds

Question 9

Buoyancy in water

Answer 9

-the upward force on an object determined on a medium by the density of the medium
-water is more dense than air so object can float, determined by weight of object though

Question 10

Water’s viscosity

Answer 10

-the measure of a fluids ability to flow
-increase viscosity =decrease ability to flow
-water is more vicious than air due to hydrogen bonds so its more difficult to move in water

Question 11

Bird adaptations in water

Answer 11

-bones are solid for diving but less dense to float
-legs are located at the rear to better move through the water
-feathers form an interlocking barrier to limit heat loss

Question 12

Mammal adaptations to water

Answer 12

-denser bones to allow for prolonged submersion
-streamlined body to better get through the water
-outer fur coat and thick blubber prevents heat loss