Chapter 3: Water and Life

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Define polar molecule
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Terms in this set (29)
Define polar molecule
A molecule with an uneven distribution of charges in different regions of the molecule
Why is water considered polar?
Overall charge unevenly distributed
Explain hydrogen bonding in terms of water. How many hydrogen bonds can a single water molecule form?
Positive hydrogen of one molecule attracted to negative oxygen of nearby molecule. Water can form four bonds.
Cohesion
Linking together of like molecules with hydrogen bonds.

Ex. Water drops on penny
Adhesion
Clinging of one substance to another.

Ex. Water in a plant cell or the lizard walking on water
Calorie
Amount of heat energy required to raise temperature of 1g of water by 1 degree Celsius. Also amount of heat energy that 1g of water cools by 1 degree Celsius
Specific Heat
Amount of heat absorbed or lost for 1g o that substance to change its temp by 1 degree Celsius. Water has a HIGH specific heat.
How does hydrogen bonding contribute to water's high specific heat?
heat breaks the hydrogen bonds before raising temperatures of water, cooling FORMS hydrogen bonds
How does Water's high specific heat contribute tot he moderation of temperature. How is this property important to life?
Water may cool air at night and warm during the day. High specific heat stabilizes ocean temperatures. This is important to life because organisms made of water are able to resist changes in their own temperature. Keeps life in balance.
Evaporation
Process by which a liquid changes to gas
Define Heat of Vaporization. Explain at least three effects of this property on living organismsHeat of Vaporization-- quantity of heat a liquid must absorb for 1g of it to be converted from the liquid to the gaseous state. 1. moderate earth's climate 2. severity of steam burns on skin 3. sweat in humansWhat would happen to organisms if ice froze at the bottom?Everything would freeze. Ice frozen on top allows life underneath to surviveWhy does ice float? Why is 4 degrees Celsius a critical temperature?Ice is less dense than water. Less than 4 degrees Celsius water begins to freeze because more of its molecules move too slow to break hydrogen bondsSolventdissolving agent of a solution WATER IS THE UNIVERSAL SOLVENTSolutionA liquid that is completely homogenous mixture of 2 or more substancesSoluteSubstance that is dissolvedWhy is water such a fine solvent?Most substances dissolve in ater. No need for ionic for ionic compoundsHydrophobicNo affinity for water (vegetable oil) water fearing...Hydrophillich2o loving (cotton)MolarityNumber of moles of solute per liter of solution. Unit of concentration used for aqueous solutionsWhat two ions form when water dissociates?hydronium ion hydroxide ionWhat is the concentration of each ion in pure water at 25 degrees celsius?10-7 MWhat has a pH of 7 pH is defined as the negative log of the hydrogen ion concentration [H+]. How is water assigned a pH of 7?Maintains equillibriumAcidSubstance that increases hydrogen ion concentration of a solutionBaseSubstance that reduces hydrogen ion concentration of a solution with higher concentration of OH- than H+ solutionHow can buffers moderate pH changes?Minimizes changes in concentration of H+ OH- in a solution. Accepts hydrogen ions from the solution when they are in excess and bonding hydrogen ions to solutionGive two reasons precipitation is more acidic today than compared to 19001. Burning of fossil fuels 2. Ocean acidificationWhat products of fossil fuel burning contribute to acid precipitation?Carbon dioxideDiscuss how CO2 emissions affect marine life and ecosystemsLowers pH. Reduces carbonate concentration. Required for calcification the production of calcium carbonate which helps build reefs.