Water is essential for life on Earth and makes the planet habitable. It has unique properties like polarity, cohesion, adhesion, and a high heat of vaporization that allow it to moderate temperatures, move nutrients in organisms, and act as a universal solvent for biochemical reactions. The polarity of the water molecule allows it to form hydrogen bonds and give water its emergent properties. Water's high specific heat also helps maintain stable temperatures suitable for life.

1. Chapter 3 Water and the Fitness of the Environment

29. The pH scale and pH values of various aqueous solutions Increasingly Acidic [H + ] > [OH – ] Increasingly Basic [H + ] < [OH – ] Neutral [H + ] = [OH – ] Oven cleaner 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH Scale Battery acid Digestive (stomach) juice, lemon juice Vinegar, beer, wine, cola Tomato juice Black coffee Rainwater Urine Pure water Human blood Seawater Milk of magnesia Household ammonia Household bleach Figure 3.8