Ch.3: Water Flashcards
is the biological medium on Earth
living organisms require XXXX
Most cells are surrounded by XXXX, and cells themselves are about 70–95% XXXX
The abundance of “Free” XXXX is the main reason the Earth is alive
WATER
The water molecule is a XXXX molecule:
The opposite ends have opposite charges
XXXX allows water molecules to form hydrogen bonds with each other
polar molecule
Water’s properties that facilitate an environment for life are:
Cohesive behavior Adhesive behavior Ability to moderate temperature High specific heat Heat of vaporization Expansion upon freezing Versatility as a solvent
Collectively, hydrogen bonds hold water molecules together, a phenomenon called
helps the transport of water against gravity in plants
Cohesion
is an attraction between different substances, for example, between water and plant cell walls
adhesion
is a measure of how hard it is to break the surface of a liquid
related to cohesion
surface tension
True or False:Water absorbs heat from warmer air and releases stored heat to cooler air
true
of a substance is the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1ºC
Specific heat
The specific heat of water is
1 cal/g/C
Water’s high specific heat can be traced to hydrogen bonding because:
Heat is absorbed when hydrogen bonds break
Heat is released when hydrogen bonds form
is transformation of a substance from liquid to gas
Evaporation
As a liquid evaporates it loses energy, its remaining surface cools, a process called
helps stabilize temperatures in organisms and bodies of water
Evaporation Cooling
Water has extremely
high heat of vaporization
Why does ice float in liquid water?
hydrogen bonds in ice are more “ordered” and abundant in ice than in liquid, making ice less dense
a liquid that is a homogeneous mixture of substances
solution
