Chapter 3-Lecture Outline Flashcards
Water is the _________ on Earth
biological medium
______________ is the only common substance to exist in the natural environment in all three physical states of matter
Water
The ______________ of water molecules allows it to interact with other molecules
Water unique emergent properties help make earth suitable for life
the structure (specifically the weak hydrogen bonding)
__________________ in the water molecule result in _____________
polar covalent bond
hydrogen bonding
In the water molecule, the electrons of polar covalent bonds spend more time near the _________ than the ______________
oxogen
hydrogen
the water molecule is thus ___________
a polar molecule
the overall change is unevenly distributed
the ____________ of water allows water molecules to form __________________ with each other
polarity
hydrogen bonds
_________________ of water contribute to earth’s suitability for life
four emergent properties
what are the four emergent properties of water that facility an environment for life
- cohesive behavior
- ability to moderate temperature (high specific heat)
- Expansion upon freezing
- versatility as a solvent
_______________: collectively hydrogen bonds hold water together, which is a phenomena
Cohesion
Cohesion help in the transport of __________________________
water against gravity in plants
________________: is an attraction between different substances, for example water and a plants cells water
Adhesion
_______________: is a measure of how hard it is to break the surface of a liquid
surface tension
Water has a __________________ surface tension due to hydrogen bonding between the molecules at the air-water interface and to the water below
unusually high
Water absorbs ______________________ and releases ___________________________
heat from warmer air
heat to cooler air
________________ is the energy of motion
kinetic energy
the kinetic energy associated with the random motion of atoms or molecules is called
thermal energy
_________________ is a measure of energy that represents the average kinetic energy of the molecule in a body of matter
temperature
Thermal energy in transfer from one body to another is defined as
heat
_____________ is the amount of heat necessary to raise the temperature of 1 gram of water 1*c
calorie (cal)
the “calories” on food packages are actually ____________
kilocalories 1 Kcal=1000 cal
the _________ is a unit of energy
joule
1 Joule=0.239 cal or 1 cal=4.184 J
_________________ is the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1*c
the specific heat of a substance
the specific heat unit is
(cal or Joule)/ g*C
Water resists a change in temperature because of its
high specific heat
Waters specific heat can be traced back to it _______________
- heat is absorbed when hydrogen bonds break
- heat is released when hydrogen bonds form
hydrogen bonding
The high specific heat of water minimized temperature fluctuations within normal limits that __________
permit life
________________ is the transformation of a substance from liquid to gas
evaporation
______________________ is the heat a liquid must absorb for 1g to be converted to gas
heat of vaporization
as a liquid evaporated, its remaining surface cools, a process called _____________________
evaporative cooling
Ice floats in liquid water because hydrogen bonds in ice are more ordered making ___________________
ice less dense in water
Waters greatest density is at ____________
4*C
If ice sank, all bodies of water would eventually _____________________ making life impossible on earth
freeze solid,
Man scientists are worried that global warming, caused by ________________________ is having a profound effect on icy environments around the globe
carbon dioxide and other global greenhouse gases,
the rate at which glaciers and arctic sea ice are disappearing is posing an extreme challenge to
animals dependent on ice for survival
_______________ is a liquid that is a completely homogeneous mixture of substances
solution
________________ is the dissolving agent of a solution
solvent
________________ is the substance that is dissolved
solute
_____________ is a solution in which water is the solvent
aqueous solution
water is a versatile solvent due to its ____________
polarity
when an ionic compound is dissolved in water, each ion is surrounded by a spare of water molecules called a ______________
hydration shell
water can resolve both
nonionic and ionic polar molecules
large polar molecules can be dissolved such as proteins can dissolve in water if they have _____________________
ionic and polar regions
is one that has affinity for water
hydrophilic substance
substance is one that does not have an affinity for water
hydrophobic substance
example of Hydrophobic: _____________
oil because they have relatively non polar bonds, these a major ingrediances of cell membranes
Biologist seeking like on other planets have concentrated their search on
planets with water
today more than 200 planets outside our solar system have been discovered and only a few of them contain water vapor. In our own solar system, Mars contains water
_____________ and _________ conditions affect organisms
acidic and basic conditions
a hydrogen atom in a hydrogen bond between two water molecules can shift _____________
from one to another
a hydrogen bond atom leaves its electron behind and is transferred as a proton is a
hydrogen ion (H+)
the molecule that lost the proton is now a
hydroxide ion (OH-)
The molecule that has an extra proton is now ___________________ though it is often represented as H+
hydronium (H3O)+
Water is in a state of __________________ in which water water molecules dissociate at the same rate at which they are being formed
dynamic equilibrium
the dissociation of water (though rare) has an effect on
life
changes in concentrations of H+ and OH- can drastically affect the
chemistry of a cell
concentrations of OH- and H+ are equal in
pure water
Biologists use the ____ to describe if something is acidic or basic
PH scale
an acid increases the concentration of _______ in a solution where as a base decreases the concentration of ___________
H+
strong acids and bases ________ in water completely
dissociate
weak acids and bases relese and accept back H+ ions but can still shift the
balance of H+ away from neutrality
Ph of
acid
base
less than 7
more than 7
the internal ph of a cell
7 ph neutral
_________: are substances that minimize changes in concentrations of H+ and OH- in a solution
buffers
buffers contain
a weak acid and a corresponding base
threats to water quality
human activy, fossil fuels, acidification,
25% of CO2 is absorbed by the ocean which results in the oceans
acidification
as sea water acidifies H+ combines with carbonate ions to produce bicarbonate; _____________ is required for calcification by many marine organisms, including reef building
calcification
