Chapter Menu Mixtures and Solutions Section 14.1Section 14.1Types of Mixtures Section 14.2Section 14.2 Solution Concentration Section 14.3Section 14.3 Factors Affecting Solvation Section 14.4Section 14.4 Colligative Properties of Solutions Exit Click a hyperlink or folder tab to view the corresponding slides.

End of Section 14-2

Section 14-3 Section 14.3 Factors Affecting Solvation Describe how intermolecular forces affect solvation. exothermic: a chemical reaction in which more energy is released than is required to break bonds in the initial reactants Define solubility. Understand what factors affect solubility.

Section 14-3 Section 14.3 Factors Affecting Solvation (cont.) solvation heat of solution unsaturated solution saturated solution supersaturated solution Henry’s law Factors such as temperature, pressure, and polarity affect the formation of solutions.

Section 14-3 The Solvation Process Solvation is the process of surrounding solute particles with solvent particles to form a solution.Solvation Solvation in water is called hydration. The attraction between dipoles of a water molecule and the ions of a crystal are greater than the attraction among ions of a crystal.

Section 14-3 The Solvation Process (cont.)

Section 14-3 The Solvation Process (cont.) Sucrose (table sugar) molecules have several O–H bonds, which become sites for hydrogen bonding with water molecules. Oil does not form a solution with water because there is little attraction between polar water molecules and nonpolar oil molecules.

Section 14-3 The Solvation Process (cont.) During solvation, the solute must separate into particles and move apart, which requires energy. The overall energy change that occurs during solution formation is called the heat of solution.heat of solution

Section 14-3 Factors That Increase the Rate of Solvation Stirring or shaking moves dissolved particles away from the contact surfaces more quickly and allows new collisions to occur. Breaking the solute into small pieces increases surface area and allows more collisions to occur. As temperature increases, rate of solvation increases.

Science or Fiction Every liter of sea water contains about 105 g of dissolved salts. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L). This means that every kilogram (roughly one litre by volume) of seawater has approximately 35 grams (1.2 oz) of dissolved salts (predominantly Sodium Chloride ions: Na+, Cl−).dissolved saltsSodium Chlorideions

Science or Fiction Scientists believe the concentration of salt in the ocean has steadily risen over the last billion years. Actually, evidence suggests that ocean salinity has been stable for billions of years, most likely as a consequence of a chemical/tectonic system which removes as much salt as is deposited.tectonic

Section 14-3 Solubility Solubility depends on the nature of the solute and solvent. “Like dissolves like” - polar dissolves polar. Unsaturated solutions are solutions that contain less dissolved solute for a given temperature and pressure than a saturated solution.Unsaturated solutions

Section 14-3 Solubility (cont.) Saturated solutions contain the maximum amount of dissolved solute for a given amount of solute at a specific temperature and pressure.Saturated solutions Solubility is affected by increasing the temperature of the solvent because the kinetic energy of the particles increases.

Section 14-3 Solubility (cont.)

Section 14-3 Solubility (cont.) A supersaturated solution contains more dissolved solute than a saturated solution at the same temperature.supersaturated solution To form a supersaturated solution, a saturated solution is formed at high temperature and then slowly cooled. Supersaturated solutions are unstable.

Section 14-3 Solubility (cont.)

Science or Fiction Conservative estimates suggest that about 15,000 tons of gold is dissolved in the world’s oceans. This is true, the world's oceans do contain gold. However, 15,000 tons of gold dissolved in the ocean mean s that the concentration is about 5x mol/L or 10 parts per quadrillion. No one has shown a method of obtaining the gold profitably.

Science or Fiction Although most solids are less soluble in cold water, oxygen gas gets more soluble in water as the temperature declines. Yes, many species of fish are very sensitive to water temperature because of its effect on the dissolved O 2 concentration as well as their overall metabolism.

Section 14-3 Solubility (cont.) Gases are less soluble in liquid solvents at high temperatures. Solubility of gases increases as its external pressure is increased. Henry’s law states that at a given temperature, the solubility (S) of a gas in a liquid is directly proportional to the pressure (P).Henry’s law

A.A B.B C.C D.D Section 14-3 Section 14.3 Assessment For a given amount, which type of solution contains the LEAST amount of solute? A.solvated B.saturated C.supersaturated D.unsaturated

A.A B.B C.C D.D Section 14-3 Section 14.3 Assessment At a given temperature, the solubility of a gas is directly proportional to what? A.volume B.mass C.molarity D.pressure