1.1/2.5 water and the fitness of the environment Flashcards
hydrogen bond definition
O- bonds with H+ on a different molecule of H2O
how many bonds can H2O form?
4
cohesion definition
polar H-bonding between like molecules
surface tension definition
measure of difficulty to break or stretch surface of liquid (H-bonding)
adhesion definition
H-bonding between unlike molecules
how does adhesion of water to vessel walls work?
Adhesion of H2O to vessel walls counters downward pull of gravity
transpiration definiton
movement of H2O up plants
how does water move up plants?
H2O clings to each other by cohesion; cling to xylem tubes by adhesion
heat definition
total amount of KE in system
temperature definition
measure intensity of heat due to average KE of molecules
water’s high specific heat:
Change temp less when absorbs/loses heat
Large bodies of water absorb and store more heat/energy → warmer coastal areas
Create stable marine/land environment
Humans ~65% H2O → stable temp, resist temp. change
H-bonding
evaporative cooling
Water has high heat of vaporization
Molecules with greatest KE leave as gas
Stable temp in lakes & ponds
Cool plants
Human sweat
liquid –> gas
insulation by ice
less dense, floating ice insulates liquid H2O below
solution
liquid, homogeneous mixture of 2+ substances
solvent
dissolving agent (liquid)
