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
the dissolving agent of a solution
solvent
the substance that is dissolved
solute
Water is a XXXXX due to its polarity, which allows it to form hydrogen bonds easily
versatile solvent
substance is one that has an affinity for water
hydrophilic
substance is one that does not have an affinity for water
hydrophobic
A hydrogen atom may leave its electron behind and now it’s a
hydrogen ion
The molecule that lost the proton is now a
hydroxide ion
Acids are referred to as
Proton donators
bases are
proton receptors
is any substance that increases the H+ concentration of a solution
acid
is any substance that reduces the H+ concentration of a solution
base
When acids and base are Mixed the together
What is produced??
salt, water,
are substances that minimize changes in concentrations of H+ and OH– in a solution
buffers
is a buffer in our bodies.
carbonic acid
Most buffers consist of an XXXX that reversibly combine with H+
acid-base pair
