Chapter 3-Concept 3.1: Polar covalent bonds in water molecules result in hydrogen bondingWater is a polar moleculePolarity allows water molecules to form hydrogen bonds with each other.-Concept 3.2: Four emergent properties of water contribute to Earth’s suitability for life.1) Cohesive behavior2) Ability to moderate temperature3) Expansion upon Freezing4) Versatility as a solvent-Cohesion of water moleculesCohesion: Hydrogen bonds holding water molecules together.Adhesion: Attraction between different forces.Surface tension: Measure of how hard it is to break the surface of a liquid.Related to cohesion.-Moderation of temperature by water.Absorbs heatWater can act to minimize temperature changes.Water can release energy with only a slight change in its temperature.-Heat and temperatureKinetic Energy is the energy of motionHeat is a measure of the total amount of kinetic energy die to molecular motion.Calorie (Cal) amount of heat required to raise the temperature of 1 gram ofwater by 1 degree Celsius.Kilocalories (kcal), where 1kcal = 1,000 Cal, Also the calories on the food. Joule (j) is another unit of energy where 1 J = .239 Cal, or 1 Cal = 4.184 J-Water’s high Specific HeatSpecific heat of a substance is the amount of heat that must be gained or lost for 1g of that substance to change by 1 degree Celsius.Water’s specific heat is 1 Cal/G/CHas a high specific heat due to hydrogen bonds, it minimizes temperature fluctuations to allow life.-Evaporative CoolingLiquid to gasHeat of vaporization is how a liquid converts to a gas, Water requires 580 Cal/g at 25 degrees CelsiusEvaporative cooling of water stabilizes temperatures in organisms and bodies of water.-IceWater is at it’s greatest density at 4 degrees Celsius. Ice floats because its molecules are more ordered than its liquid form. By being less dense it floats, protecting organisms around it.-Solvent Water as a solvent dissolves polar molecules Not universal solvent. When it acts as a solvent it creates a hydration cell around the ions.-Hydrophilic/HydrophobicHydrophilic compounds will dissolve in waterColloids are fine suspensions in water.Cotton although it can dissolve wont because it is to big of a molecule.Hydrophobic compounds will not dissolve in water.Most biological chemical reactions occur in aqueous solutions-Concept 3.3 Acid/Base affects living organisms2H2O H3O+ + OH-Hydronium (H+)/OH-(Hydroxide)Rate is constant for disassociation and re-association.-Concept 3.3 Acid/Base effect living organismsAcid has high H+ and low OH-Base has low H+ and high OH--pH ScaleAt 25 degrees Celsius H+ and OH- => [H+][OH-] = 10-14 pH of a solution is determined by pH=log-[H+] For a neutral solution, [H+] is 10-7pH=-(-7)=7 Most biofluids have between 6 to 8 pHBuffersMinimize changes in
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