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Water, H2O, and hexane, C6H14, are commonly used as laboratory solvents because they have different physical properties and are able to dissolve different types of solutes. Some physical properties of water and hexane are listed on the table below. 6

A sample of normal rainwater has a pH value of 5.6 due to dissolved carbon dioxide gas from the atmosphere. Acid rain is formed when other gases, such as sulfur dioxide, dissolve in rainwater, which can result in lake water with a pH value of 4.6. The equation below represents the reaction of water with SO2(g). 7

A 100.-gram sample of liquid water is heated from 20.0°C to 50.0°C. Enough KClO3(s) is dissolved in the sample of water at 50.0°C to form a saturated solution.

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A bottled water label lists the ions dissolved in the water. The table below lists the mass of some ions dissolved in a 500.-gram sample of the bottled water. 9

At 23°C, 85.0 grams of NaNO3(s) are dissolved in 100. grams of H2O(ℓ).

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In a laboratory investigation, a student is given a sample that is a mixture of 3.0 grams of NaCl(s) and 4.0 grams of sand, which is mostly SiO2(s). The purpose of the investigation is to separate and recover the compounds in the sample. In the first step, the student places the sample in a 250-mL flask. Then, 50. grams of distilled water are added to the flask, and the contents are thoroughly stirred. The mixture in the flask is then filtered, using the equipment represented by the diagram below. 11

A saturated solution of sulfur dioxide is prepared by dissolving SO2(g) in 100. g of water at 10.°C and standard pressure.

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Carbon dioxide is slightly soluble in seawater. As carbon dioxide levels in the atmosphere increase, more CO2 dissolves in seawater, making the seawater more acidic because carbonic acid, H2CO3(aq), is formed.

Seawater also contains aqueous calcium carbonate, CaCO3(aq), which is used by some marine organisms to make their hard exoskeletons. As the acidity of the sea water changes, the solubility of CaCO3 also changes, as shown in the graph below. 13 