Chapter 3: Water and Life

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Define polar molecule
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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.