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33 Cards in this Set
- Front
- Back
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What chemical properties are special for water? (4)
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High specific heat, high heat of vaporization, powerful solvent and slight tendency to dissociate
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What mechanical properties are special for water? (3)
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Cohesive, adhesive and expands when frozen
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Why does H2O have special properties?
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H2O can hydrogen bond with other H2O molecules
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Define Kinetic Energy
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energy of motion
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Define heat
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total amount of KE in matter
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Define specific heat
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amount of heat that must be gained or lost for 1g of sample to change temp by 1 degree celcius
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Why is High Specific Heat important? (3)
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A. Maintains constant body temp
B. Maintains constant temp in the ocean C. Regulates temperature change |
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Define Heat of Vaporization
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amount of heat needed to convert 1g of liquid to gas
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Why is heat of vaporization important?
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evaporative cooling - H2O needs a lot of energy to switch from liquid to gas (sweating)
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Define hydrophilic
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Dissolves in water
-polar and ionic substances |
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Define hydrophobic
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Doesn't dissolve in water
-non-polar substances |
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Why is water being a powerful solvent important? (3)
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Many important substances are dissolved in water from substances such as cytoplasm, blood and sap
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What is the concentration of H+?
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1 x 10^-7 M
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What is the concentration of OH-?
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1 x 10^-7 M
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How do you find the pH of a solution if the concentration of H+ is 1 x 10^-5?
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The pH is the exponent.
1 x 10^-5 = pH of 5 |
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What does a neutral pH mean?
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H and OH are equal
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How do you find the pOH of a solution if the OH- is 1 x 10^-11?
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The pOH is the exponent.
1 x 10^-11 = pOH of 11 |
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What's the difference between pH and pOH scales?
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The two are inversed
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How do you find the ion product of water?
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[H+][OH-]= 1 x 10^-14
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How do you find the pH if you only have the pOH?
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pH + pOH = 14
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Why is the slight tendency to dissociate important?
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If the pH of the blood changes even a little, you'll die.
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What changes pH or pOH?
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Acids and bases
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Define acids
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H+ donor (add H+)
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Define bases
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H+ acceptor (decreases H+)
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Define buffers
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Substance that prevents changes in pH
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How do buffers prevent change in pH?
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It acts as a reservoir of H+
-donates H+ when low -removes H+ when high |
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Define cohesive
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Like clings to Like
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Define adhesive
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Like clings to unlike
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What do cohesive properties do for water?
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Gives H2O surface tension
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What do adhesive properties do for water?
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Lets water cling to other objects
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How are cohesive and adhesive properties important for water?
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They allow capillary action, which is important for transporting water through trees
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Why does water expand when frozen?
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Liquid H2O is moving fast enough to break Hbonds, but solid H2O is slow and can be bound together and held at the max distance apart
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Why is floating ice important?
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So animals and plants in lakes can live through the winter.
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