Water is a polar molecule with the negative end toward the oxygen and the positive end toward the hydrogens. Hydrogen bonding is a vital part of why water has its exceptional properties. These include unusually high boiling points, specific heat and heat capacity.

One of the concepts we introduce in this section is the vapor pressure of water. Table 7.2 shows that it sharply increases with temperature. The vapor pressure of water can be approximately calculated at any temperature, as you will find at the site http://antoine.fsu.umd.edu/chem/senese/101/solutions/faq/predicting-DO.shtml. Try a few temperature values, using a barometric pressure of 760 mm Hg (a typical pressure at the Earth's surface). Does the calculated water pressure about equal those values listed in Table 7.2?

There is another space in calculator called "Saturated DO Concentration, mg/L". DO stands for "dissolved oxygen", and is a measure of the maximum oxygen concentration in pure water at a particular temperature. The concentration unit mg/L is equal to parts per million (ppm). What happens to the DO as the temperature increases? Please make a graph that includes 10 values of DO at 10 different temperatures. Can you think of any environmental consequences to the changes that you see? We will discuss this further in Sections 7.2 and 11.6.

Water's structure makes it an excellent solvent for many compounds.

Here's a toughie, but goody. Several years ago, workers at Pollution Engineering worked out an equation for determining the solubilities of benzene and related compounds, as well as salts in water. Please go to the site at http://www.pollutionengineering.com/archives/1995/pol0601.95/06adp2f0.htm and do try some calculations, as outlined. They guide you through some in the lower part of their paper. Record your data, and explain why the solubilities are either as low or as high as they are. What are some implications of your data?

Hard water is so-named because it is hard to wash things in, and because hard deposits settle out when it is heated. Soaps form a grimy residue with hard water metals, especially calcium. Detergents are soluble in hard water. Municipal water supplies are made potable via large wastewater treatment plants.

We often talk of chemical processes without discussing the people who make them possible. Please read the material at the Web site http://www.bls.gov/oco/ocos229.htm and write a two page essay on the job responsibilities and educational background of a Wastewater Treatment Plant Operator.

Some of water's properties change when substances are dissolved in it. Among these are its vapor pressure, freezing point, boiling point and osmotic pressure.

Prestone, a division of Honeywell International, is often identified with antifreeze. At their site http://www.prestone.com/home/index.html, you will note a variety of products that are related to colligative properties. What are some of these properties, and by looking at this site or others, can you explain how they do what they do?