2.2 Water Flashcards
What are the properties of water?
excellent solvent
high heat capacity & vaporization
low ice density
cohesive and adhesive properties
helps maintain homeostasis
Define hydrophillic
water forms hydrogen bonds with polar molecules, ions and water
water loving
define hydrophobic
non-polar molecules ex. oils and fats
water fearing
What occurs in liquid water?
hydrogen bonds constantly form and break as water molecules move
What is kinetic energy?
motion of water due to heat in the system
How do water molecules react in steam and water vapor?
They move quickly= higher kinetic energy- more heat
What occurs in ice?
temp less= no kinetic energy= less movement- stationary hydrogen bonds
Why does ice have low density?
due to water molecules being pushed farther apart compared to liquid molecules- bonds are not moving & changing
Why are other liquids different from water?
they pack even more compared to water due to less kinetic energy- more density
How does ice benefit organisms?
Ice on lakes act as an insulating barrier; protects organisms in waters from freezing
How would organisms react without this property of ice?
They would freeze due to the expansion of ice and ice crystals would rupture delicate membranes of cells need for life
What caused water’s high heat capacity?
caused by hydrogen bonding
what is specific heat?
the amount of heat one gram of a substance must absorb or lose to change its temperature 1*C
What is the specific heat for water?
1 calorie; takes a long time to cool and heat
compared to land
How is water high heat capacity beneficial for organisms?
water is used to disperse heat in warm-blooded animals- transports heat from warm places to cool
Define water’s high heat of vaporization
the amount of energy to change 1 g of a liquid to gas- 569 calorie
What is the process of water’s vaporization?
water heats- difficult for water to separate due to hydrogen bonding
WHat is a heat sink or heat reservoir?
unable to heat up quickly
evaporization
surface molecules escape and vaporize causing the heat to go away and the environment to cool
How does water’s high heat vaporization help in organisms?
evaporation of sweat- cooling- homeostasis
Why does water have amazing solvent properties
due to its polar covalent properties and sphere of hydration
What is the sphere of hydration?
surrounding a particle with hydrogen bonds from water molecules to keep particles in water
What is disassociation
when ionic compounds are added to water, the individual ions react with polar regions of water molecules, and ionic bonds are disrupted
It occurs when atoms or a group break off from molecules to form ions
Define cohesion
water makes dome shape; water molecules attract each other which keeps them together even when there’s no more room
define surface tension
capacity of a substance to withstand rupture under tension; (placing a needle)
define adhesion
attraction between water molecules and other molecules; stronger than cohesion sometimes
capillary actionw
water climbs on the side of the tube- charged glass walls
How is water’s cohesive and adhesive properties used in organisms?
transport water from roots to leaves
insects float on water
What is limitus
ph paper- pH indicator
What are buffers
absrobs excess H+ and OH- to maintain pH for survival
What are the buffers of blood?
carbonic acid, bicarbonate ion and CO2 and antacids
