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27 Cards in this Set
- Front
- Back
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What is a Polar Covelant Bond?
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covelent bond formed between two atoms that differ in electronnegativeity, shared electrons are pulled over to the more electronegative atom, makeing it slightly negative and the other atom slighty positive
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What is a Polar Molecule?
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molecule with an uneven distribution of charge in diffrent regions of the molecule
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What are the properties of Water?
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1.Properties of water arise from Hydrogen Bonding
2.In liquid form hydogen bonds are fragile( 1/20 strength of colenent bond 3. H-Bonds form, break, reform within a few trillionths of a sec 4. At any instant, most water molecules are bonded to other water molecules |
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What is Cohension?
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linking together of like molecules,often by H-bonds
*contributes to transpot of water and dissolved nutrients against gravity in plants |
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What is Adhension?
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linking together of like molecules, often by H- bonds contributes to transport of water and disole of nutrients against the gravity in plants
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What is surface tension?
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Measure of difficulty in stretching or breaking the surface of a liquid
*water is stronger than most liquidsa because of the H-bond |
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What is Heat?
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total amount of kenetic energy due to the random motion of atoms or molecules in a body of matter
*Kenetic Energy-energy associated with the relative motion of objects |
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What is Tempeture?
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measure fo average kenetic energy of moleculesrather than the toasl amount of energy in matter
*measures molecules movement- not how hot or cold something is *heat passes from warmer to cooler |
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What is Specific Heat?
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amount of heat required for a substance to change it tempeture by 1*C
*water is usually specific heat due to H-Bonds *water will change its tempeture less when it obsorbes or losses heat |
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What is Heat of Vaporation?
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the quiantity of heat liquids must absorb for 1g to be converted from liquid to gas
*Water has an unusually high heat of vaporization due to H-bonding *Helps to Moderate earths climate |
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What is Evaporation Cooling?
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propety of a liquid whereby the surface becomes cooler during evoration, owning to a loss of molecules with the greatest kinetic energy to the gasous state
*contributes to thermal stability in lakes and ponds *prevent terestrial organisms from overheating |
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How doe water float on ice?
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1.Water is kess dense as a solid than a liquid
2. Due to H-Bonding-10% less 0 thasn 4*C 3.As ice freazes it floates 4. As ice frezzes it floats, insulating the water below, if frozen ice sank, then large bodies of water would freeze solid, never thawing 5.Allows life to exist under the frozen surface |
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What is a Solution?
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liquid that is a homogenous mixture of two or more substances
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What is a Solvent?
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dissolving agent (water = “universal” solvent)
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What is a Solute?
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substance being dissolved in the solvent
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What is a Hydration shell?
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sphere of water molecules that surrounds a dissolved ion
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What is Hydrophilic?
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any polar substance that has an affinity for water; water soluble
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What is Hydrophobic?
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any nonpolar substance that repels water; water insoluble
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What is a a Hydrogen Ion? (H+)
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single proton with a 1+ charge
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What is a Hydroxide Ion? (OH-)
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water molecule that lost a hydrogen ion resulting in a 1- charge
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What is a Hydronium Ion? (H3O+)
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water molecule with an extra hydrogen proton
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What is a Acid?
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substance that increases H ion concentration of a solution
0 – 6.9 on pH scale |
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What is a Base?
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substance that decreases H ion concentration of a solution
7.1 – 14 on pH scale |
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What is Neutral?
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substance in which H ion and OH ion concentrations are equal
7.0 on pH scale |
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What are Buffers?
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substances that minimize changes in H ion and OH ion concentrations
•Blood pH = 7.4 (+/- .4 pH = death) •0.01 M of a strong acid to 1L water → pH drops from 7.0 to 2.0 •M of a strong acid to 1L blood → pH drops from 7.4 to 7.3 |
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What is a Acid precipitation?
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rain, snow or fog with a pH lower than 5.2
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What is a Ocean acidification
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when CO2 dissolves in seawater, it reacts with water to form carbonic acid which lowers ocean pH
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