tailieunhanh - Ebook Chemistry a molecular approach (4th edition): Part 2

(BQ) Part 2 book "Chemistry a molecular approach" has contents: Chemical kinetics, chemical equilibrium, aqueous ionic equilibrium, free energy and thermodynamics, free energy and thermodynamics, organic chemistry, radioactivity and nuclear chemistry, chemistry of the nonmetals,.and other contents. | Exercises Sea Salts Seawater having a salinity of 35 g>kg contains 35 grams of NaCl per one kilogram of seawater. Use the information provided in the figures to answer the following questions: a. Calculate the freezing point of a sample of seawater having the highest salinity. Calculate the freezing point of a sample of seawater having the lowest salinity. Use a Van’t Hoff Factor of in your calculation. Assume the two samples contain water as the solvent and NaCl as the solute. Chloride 55% () Calcium () Potassium () Water (965g) Sodium () Magnesium () Minor constituents () b. Figure c▼ is a proposed graph of the freezing temperature of saltwater versus the amount of salinity. A student claims t ­ hat saltwater having a salinity of 280 g NaCl >kg of saltwater freezes at -20°C. Is this claim accurate? Explain. Salt (35g) ▲ Figure a  Cations and Anions in Ocean Water  Figure b▼ illustrates the salinity of the oceans on Earth in grams of dissolved material (solute) per kilogram of ­eawater s ( ­ solution) or parts per thousand (ppt). 0 Freezing point (°C) Sulfate () 621 -5 -10 -15 -20 -25 0 Salinity (ppt) more than 37 37 36 35 34 less than 34 ▲ Figure b  Salinity of Seawater in the Earth’s Oceans  100 200 Salinity (g/kg) 300 400 ▲ Figure c  Salinity of Saltwater Versus the Freezing Point of Seawater  c. Use the information provided in Figure b and redraw the graph in Figure c using a range of salinity values from six different oceans. The y-axis should be the freezing point of water, and the x-axis should be the salinity of seawater in units of grams of NaCl >kg of seawater. Does Figure c provide an accurate view of the freezing point of the oceans? Because most of the dissolved minerals in seawater is s ­odium chloride, we can make the assumption that seawater Answers to Conceptual Connections Solubility The first alcohol on the list is methanol, .