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46 Cards in this Set
- Front
- Back
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Most cells are surrounded by water, and cells themselves are about ___water |
70-95% |
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The water molecule is a |
Polar molecule(overall charge is unevenly distributed): the opposite ends have opposite charges |
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_____ allows water molecules to form hydrogen bonds |
Polarity |
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4 properties of water that facilitate an environment for life are: |
-Cohesive behavior -Ability to moderate temperature -Expansion upon freezing -Versatility as a solvent |
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Hydrogen bonds hold water molecules together in a phenomenon called____ |
Cohesion, helps the transport of water against gravity (Plants) |
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Adhesion |
Attraction between different substances (water and plant cell walls) |
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Measure of how hard it is to break the surface of liquid |
Surface tension (related to cohesion) |
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Moderation of temperature by water |
-Absorbs heat from warmer air and releases stored heat to cooler air -Absorbs and releases a large amount of heat with only a slight change in its own temperature -effective heat bank |
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Energy of motion |
Kinetic energy |
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Measure of the total amount of kinetic energy due to molecular motion |
Heat |
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Measure of the intensity of heat due to the average kinetic energy of molecules |
Temperature |
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amount of heat required to raise the temperature of 1g of water by 1*C (*F=9/5*C+32) |
Calorie (cal) |
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Rhw "calories on food packages are actually ____ |
Kilocalories (kcal) where 1kcal=1,000cal |
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Joule (J) |
another unit of energy where 1 J = 0.239 cal, or 1 cal = 4.184 J |
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Amount of heat that must be absorbed or lost for 1g of that substance to change its temperature by 1*C |
Specific heat |
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Water resists changing its temperature because of its |
Specific heat |
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Heat is abosorbed when___ |
hydrogen bonds break |
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Heat is released when___ |
hydrogen bonds form |
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Evaporation |
transformation of a substance from liquid to gas |
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Heat a liquid must absorb for 1g to be converted to gas |
Heat of vaporization |
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As a liquid evaporates, its remaining surface cools, a process called ___ |
Evaporative cooling( helps stabilize temperature in organisms and bodies of water |
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Liquid that is homogeneous mixture of two or more subsances |
Solution |
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The dissolving agent of a solution |
Solvent |
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The substance that is dissolved |
Solute |
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One in which water is the solvent |
Aqueous Solution |
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Water can also dissolve compounds made of ____ such as sugars |
Nonionic polar molecules |
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Even large polar molecules such as proteins can dissolve in water if they have _____ regions |
Ionic and polar |
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One that has an affinity for water |
Hydrophilic |
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One that does not have an affinity for water |
Hydrophobic (results from a prevalence of relatively nonpolar covalent bonds) |
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Stable suspension of fine particles in a liquid |
Colloid |
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Sum of all masses of all atoms in a molecule |
Molecular mass |
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Number of molecules |
Mole(mol) = 6.02x10^23 molecules |
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Avogadro's number and the unit dalton were defined such that |
6.02x10^23 daltons= 1 g |
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Number of moles of solute per liter of solution |
Molarity |
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Hydrogen atom leaves its electron behind and is transferred as a proton |
Hydrogen ion (H+) |
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Water molecule with extra proton is now ______ Though often represented as H+ |
Hydronium ion (H3O+) |
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Water molecule that lost the proton is no a |
Hydroxide ion (OH-) |
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Concentrations of H+ and OH- are |
Equal in pure water |
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Adding certain solutes, called _____ modifies the concentration of H+ and OH- |
Acids and bases |
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Biologist use the ______ to describe whether a solution is acidic or basic |
pH scale |
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Substance that increases the H+ concentration of a solution |
Acid (Weak acid: carbonic acid, Strong acid: HCI) |
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Any substance that reduces the H+ concentration of a solution |
Base (Weak base: NH3, strong base: NaOH) |
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pH Scale |
[H+][OH-]=10^-14 pH=-log[H+] pOH=-log[OH-] pH+pOH=14 |
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Substances that minimize changes in concentratrions of H+ and OH- in a solution |
Buffers |
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CO2 dissolved in sea water forms carbonic acid this process is called ___ |
Ocean acidification |
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Rain, fog, or snow with a pH lower than 5.2 |
Acid precipitation |
