BIOL 1441 1st Edition Lecture 3 Outline of Last Lecture I Chemical bonds Outline of Current Lecture part one of chapter 3 I Facts about water II Properties of water Current Lecture I II Facts a Water supports all life b Organisms are composed of mostly water i Humans are 70 water c Life on earth began with water d Cells are surrounded by water e Cells are 70 95 water f Earth is 75 water g Water is the only substance that naturally exists in all 3 states liquid solid gas h HYDROGEN BONDING IS RESPONSIBLE FOR WATER PROPERTIES i Structure of water i Unique properties arise from attractions between polar molecules 1 b c of hydrogen bonding Water properties a Cohesion binds a substance together i H2O molecules attracted to each other H bonds ii Transport of water and dissolved nutrients against gravity in plants iii Water evaporates from leaves iv Upward pull is transported throughout all cells down to roots v Adhesion clinging of one substance to another 1 Water adheres to walls of cells vi Surface tension measure of how difficult it is to stretch or break the surface of a liquid 1 Water has greater surface tension than most liquids These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 2 Interfere between water and air ordered arrangement of water molecules a Behaves like an invisible film 3 Creates waves a Waves are necessary for rapid oxygen diffusion in lakes and oceans b Moderation of temperature i Heat bank stores heat ii Water can lose and gain a lot of heat and not change temp iii Kinetic energy energy of motion iv Heat total amount of kinetic energy due to molecular motion in a body of matter v Temperature average of kinetic energy vi Heat is a form of energy depends on volume of matter vii Average speed of molecules increase temp increases viii Heat and temp are related but not the same 1 Ex You have a higher temp than the ocean but the ocean has more heat ix Energy will flow from high to low concentration 1 Heat will always pass to the cooler object until the 2 are the same temperature a Ex Ice doesn t add coolness to a drink ice absorbs heat from warm liquid x Water freezes 0 C xi Water boils 100 C xii Human body 37 C xiii Room temp 20 25 C xiv Refrigerator 4 C xv Measure of heat 1 Calorie amount of heat it takes to raise temp of 1 gram of water by 1 C 2 Kilocalorie 1000 cal a Calories on food packages 3 Joule a 1J 239 cal 4 Specific heat amount of heat that must be absorbed or lost for 1g of that substance to change its temp by 1 C 5 Water specific heat 1 cal j C because hydrogen bonding a Unusually high 6 Beer 6cal g C 7 Metal has much lower specific heat a Pot of water on stove pot gets hot a lot faster than the water 8 Heat absorbed break Hbonds 9 Heat released forms Hbonds 10 Night winter water releasing heat warming the air 11 Stabilizes ocean temp
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