Water Chemistry and Soil Science

4350 Words18 Pages
Water is one of the most important substances on earth. We swim, bathe, boat, and fish in it. It carries our waste from our homes and is used in the generation of electrical power. We drink it in a variety of forms: pure water, soft drinks, tea, coffee, margaritas, and so on. Water, in one form or another, moderates the temperature of the earth and of our bodies. In the area of biochemistry, water is also one of the lead actors. Our bodies are about 70 percent water. Water plays a role in the transport of material to and from cells. And many, many aqueous solutions take part in the biochemical reactions in the body. In this chapter, we examine the structure and properties of the water molecule. We explain how water behaves as a solvent. We look at the properties of acids and bases and the equilibria that they may undergo. Finally, we discuss the pH scale and buffers, including the infamous Henderson-Hasselbalch equation. Sit back, grab a glass of water, and dive in! The Fundamentals of H2O Water is essential to life; in fact, human beings are essentially big sacks of water. Water accounts for 60–95 percent of our living cells, and 55 percent of the water in the human body is in intracellular fluids. The remaining 45 percent (extracellular) is divided between the following:  Plasma (8 percent)  Interstitial and lymph (22 percent)  Connective tissue, cartilage, and bone (15 percent) Water also is necessary as a solvent for the multitude of biochemical reactions that occur in the body:  Water acts as a transport medium across membranes, carrying substances into and out of cells.  Water helps maintain the temperature of the body.  Water acts as a solvent (carrying dissolved chemicals) in the digestive and waste excretion systems. Healthy humans have an intake/loss of about two liters of water per day. The intake is about 45 percent
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