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HW # 12 – Read Class Notes; Complete Handout Front Side Only!. Aim: How much solute can a solvent hold? Do Now: Based on Reference Table F , which of these salts is the best electrolyte? sodium nitrate (3) silver chloride magnesium carbonate (4) barium sulfate.
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HW # 12 – Read Class Notes; Complete Handout Front Side Only! Aim: How much solute can a solvent hold? Do Now: Based on Reference Table F, which of these salts is the best electrolyte? • sodium nitrate (3) silver chloride • magnesium carbonate (4) barium sulfate
Based on Reference Table F, which of these salts is the best electrolyte? • sodium nitrate (3) silver chloride • magnesium carbonate (4) barium sulfate • Electrolyte: a substance that conducts electricity when dissolved in water. • Dissolved = Soluble • Sodium nitrate • (Soluble) • Magnesium carbonate • (Insoluble) • Silver chloride • (Soluble) • (Insoluble) • Barium sulfate • (Soluble) • (Insoluble)
Solubility: the amount of a substance that will dissolve in a given amount of another substance at a specified temperature Ex. 40 grams of NaCl can dissolve in 100 grams of water at 100°C Dilute: very little solute compared to solvent When the solute amount is less than half the amount of the solvent = 5g NaCl/100g water Concentrated: a lot of solute compared to solvent When the solute amount is more than half the amount of the solvent = 85g NaCl/100g water Water has its limits!
Saturated solution: contains the most solute that the solvent will allow at a given temperature Unsaturated solution: contains less solute than a saturated solution Supersaturated solution: contains more solute than a saturated solution
Supersaturated solution: The rate of dissolving < the rate of crystallization. Unsaturated solution: The rate of dissolving > the rate of crystallization. Saturated solution: The rate of dissolving = the rate of crystallization. SOLUTION EQUILIBRIUM
How to Use Table G X axis = temperature (°C) Y axis = amount of solute per 100 g of H20 Saturated solution: “on the line” Ex. How many grams of NaCl will saturate 100g of H20 at 100°C? Answer: 40 grams Unsaturated: “below the line” Anything less than 40 grams. Supersaturated: “above the line” Anything more than 40 grams.
(watch for multiples of 100g!!!) How many grams of NaNO3 are needed to saturate 200g of H20 at 40°C? Answer: At 100g of H20 = 105g. At 200g of H20, 105g x 2 = 210g At 50g of H20, 105g / 2 = 52.5g
A solution contains 35 grams of KNO3 dissolved in 100 grams of water at 40°C. How would you describe this solution? • Unsaturated • Dilute How much more KNO3 would have to be added to make it a saturated solution? • 29 g (2) 24 g (3) 12 g (4) 4 g
A saturated solution of NaNO3 is prepared at 60.°C using 100. grams of water. As this solution is cooled to 10.°C, NaNO3 precipitates (settles) out of the solution. The resulting solution is saturated. Approximately how many grams of NaNO3 settled out of the original solution? (1) 46 g (2) 61 g (3) 85 g (4) 126 g