Fig. 3-1

Ch. 3 Water & Fitness of the Environment

Water The only common substance to exist in the natural environment as S, L & G Life began in the water & evolved there for 3 billion years before spreading to land Water molecules are polar

Fig. 3-2 Hydrogen bond  – – H  + + H O — —  + +  + +  + +  – –  – –  – – Water

4 Emergent Properties of Water Cohesion / Adhesion –Method plants use to bring water to the top –Explains surface tension

Fig. 3-3 Water-conducting cells Adhesion Cohesion 150 µm Direction of water movement Water transport

Fig. 3-4 Surface Tension

4 Emergent Properties of Water Cohesion / Adhesion Moderates Temperature –High Specific Heat = It takes a lot of heat to raise the temperature of water. Affects climate –High Heat of Vaporization = It takes a lot of heat to vaporize water. Evaporative cooling.

Fig. 3-5 San Diego 72° 40 miles Pacific Ocean 70s (°F ) 80s 90s 100s Santa Barbara 73° Los Angeles (Airport) 75° Burbank 90° San Bernardino 100° Riverside 96° Santa Ana 84° Palm Springs 106° Water Moderates Temperature due to High Specific Heat

4 Emergent Properties of Water Cohesion / Adhesion Moderates Temperature S is Less Dense that Liquid –Ice Floats –Ice Insulates Bodies of Water

Fig. 3-6 Hydrogen bond Liquid water Hydrogen bonds break and re-form Ice Hydrogen bonds are stable Water is less dense in the solid form so ice floats

4 Emergent Properties of Water Cohesion / Adhesion Moderates Temperature Solid is Less Dense that Liquid Solvent of Life –“Like dissolves Like” Rule –Polar water dissolves polar (charged) solutes

Fig. 3-7 Cl – Na Cl – – – – – – – – – Na + – – – + Like Dissolve Like

Fig. 3-8 (a) Lysozyme molecule in a nonaqueous environment (b) Lysozyme molecule (purple) in an aqueous environment (c) Ionic and polar regions on the protein’s surface attract water molecules. Proteins are water soluble so can be transported in the blood which is mostly water.

Acid & Base Conditions Affect Organisms Neutral, pH = 7Water H 3 O+ = OH- Acidic, pH H 3 O+ Basic, pH > 7> OH-

Fig. 3-UN2 Hydronium ion (H 3 O + ) Hydroxide ion (OH – ) 2H 2 O H H H H H H H H O O O O Dissociation of Water to Form Ions

Fig. 3-9 Neutral solution Acidic solution Basic solution OH – H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ Neutral [H + ] = [OH – ] Increasingly Acidic [H + ] > [OH – ] Increasingly Basic [H + ] < [OH – ] pH Scale Battery acid Gastric juice, lemon juice Vinegar, beer, wine, cola Tomato juice Black coffee Rainwater Urine Saliva Pure water Human blood, tears Seawater 9 10 Milk of magnesia Household ammonia Household bleach Oven cleaner The pH scale

Fig More acidic 0 Acid rain Acid rain Normal rain More basic Acid Deposition