Wake-up 1.How many moles of NaCl are there is 12 L of 2 M solution? 2.What mass (in grams) of NaCl would be contained in #1? Solutions II Mole Fraction, Dilution Solubility Molarity and Molality Summary Table MolarityMolality Symbol Equation Units Mm Mol of solute Liters of solution Mol of solute Kilogram of solution mol L mol kg Mole Fraction ( ) Ratio of the number of moles of a solute to the total number of moles in a solution What is the ratio of yellow fish to the total number of fish? :9 Mole Fraction Equation Example # g C 2 H 5 OH 50 g C 2 H 5 OH 1 mol C 2 H 5 OH = mol C 2 H 5 OH (0.024 mol C 2 H 5 OH mol H 2 O) = mol Calculate the mole fraction of ethanol, C 2 H 5 OH, in a solution prepared by dissolving 1.20 g of ethanol in 16.8 g of water g H 2 O 18 g H 2 O 1 mol H 2 O = 0.93 mol H 2 O Example #2 What is the mole fraction of xenon in a mixture that contains g of xenon g of argon and 3.62 g of neon ? Review Solution Terms The amount of solute changes depending on solution Concentration Amount of solute in a solution ConcentratedDilute Large amount of solute in a solution Small amount of solute in a solution Dilute Concentrated You order SWEET tea on a hot day. It arrives and you take a giant gulp. YUCK! They served you unsweet and the waiter is nowhere in sight. Sugar packets are on the table. Do you dare? Why or why not? Three conditions of solution equilibrium Unsaturated: contains LESS solute than a saturated solution Three conditions of solution equilibrium Saturated: contains the MAXIUMUM amount of dissolved solute at specified temp Three conditions of solution equilibrium Super saturated: contains MORE dissolved solute than a saturated solution Example of Supersaturated - Carbonated water is supersaturated with carbon dioxide - Air can be supersaturated with water forming clouds/precipitation -Hand Warmers use supersaturated sodium acetate. (Hand Warmers in Action)Hand Warmers in Action Supersaturated solutions in Nature Normal ocean water has a salt level of 30 percent. Some environments containing 10 times the salt of the ocean; Salt precipitates out Supersaturated Solutions in Nature? The Great Salt Lake, Utah Halophiles can be found in: The Dead Sea Where is the Dead Sea? Many people travel to the Dead Sea to swim in the salt and cover themselves with its mud.it is thought to heal It is also VERY buoyant!!! Video-Start 2:02 Dilutions 13 Whats the only difference? How many solute parts? Dilution The process of reducing the concentration of a solute in solution by adding more solvent Dilution Equation M = Molarity and V = Volume Example #1 To what volume must 1.0 L of a 6.0 M solution of HCl be diluted in order to prepare a 0.2 M solution? M 1 V 1 = M 2 V 2 M 1 = 6.0 M V 1 = 1.0 L M 2 = 0.2 M V 2 = ? (0.1 L)(6.0 M) = (0.2 M)(V 2 ) V 2 = 30 L Example #2 What volume of 16 M sulfuric acid must be used to prepare 1.5 L of a 0.10 M sulfuric acid solution? Kool-Aid Lab You have 20 minutes to work on lab Any work that is not completed, should be finished over the weekend Solubility The amount of solute required to form a saturated solution with a specific amount of solvent at a specified temperature. (grams of solute per 100 grams of solvent) Solubility depends. 1.Nature of the solute and solvent 2.Temperature: Must be specified 3.Pressure (for gases): Must be specified Solubility Curves A graph showing the relationship between solubility and temperature. Line represents saturated solution. Above line - supersaturated; Below the line - unsaturated Practice with Solubility Curves