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23 Cards in this Set
- Front
- Back
Molecular formula of water |
H2O |
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Structural formula of water |
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Why are water molecules are polar |
H 2.2 O 3.4 there is more than .5 difference in electromagnetic charge |
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Hydrogen bond between water molecules |
the attraction between oppositely charged regions of polar molecules |
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Cohesion |
hold together |
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Adhesion |
Attraction to charged surfaces |
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Hydrophilic |
Attraction to water - Charged substances dissolve in water |
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Hydrophobic |
Repelled by water - noncharged won't dissolve in water |
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Liquid water is necessary for life on earth |
because 75% of living things are water and water is necessary for cell processes as well as regulate temperature and environment |
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Water's high heat capacity is important to living things as a temperature buffer |
It helps regulate environmental temperature and since all living things are made of mostly water they are better able to resist change of their temperature |
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Water's high heat vaporization is important to living things |
change from liquid to gas requires significant energy so evaporation from surface takes away heat and helps stabilize temperature |
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Why does ice float |
Water is one of the few substances that becomes less dense in solid form. If ice sank then eventually ponds lakes and ocean would freeze solid |
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Water is the basis of scientific measurement |
calorie (cal) + amount of heat it takes to raise the temperature of 1 gram of water by 1 degree. 1g= 1mL at sea level. It is based on water |
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Aqueous solution |
solute dissolved in water |
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Molarity (M) |
Moles of solute per liter solution 1M solution= 1 mole (6x10 ^23) of solute in 1L of solition |
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Formula for concentration using Molarity |
(Molecular weight)(L)(M)=________g Divided by 1000 for mL |
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Percentage % |
Grams of solid solute per mL of a solution 100% solution = 1g of solute in 1mL of solution or = 1mL of solute in 1mL of solution |
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Formula concentration using Percentage |
(percent in desimal)(mL)=_________g/mL multiply by 1000 if L |
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pH |
is the hydrogen concentration in an aqueous solution. |
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pH Scale |
The higher the hydrogen concentration the lower the number on the pH scale. |
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Acidic |
0-6.99 |
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Basic |
7.01-14 |
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Buffer |
A chemical substance that maintains the pH of a solution. By either donating a hydrogen or accepting a hydrogen from the solution |