classification of matter solutions solutions are homogeneous mixtures

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Slide 2 Classification of Matter Solutions Solutions are homogeneous mixtures Slide 3 Solute A solute is the dissolved substance in a solution. A solvent is the dissolving medium in a solution. Solvent Salt in salt water Sugar in soda drinks Carbon dioxide in soda drinks Water in salt waterWater in soda Slide 4 If less than one gram of the substance will dissolve in 100 grams (or 100 mL) of solvent, the substance is considered insoluble. If more than ten grams of substance will dissolve in 100 grams (or 100 mL) of solvent, the substance is considered soluble. If between one and ten grams of a substance will dissolve in 100 grams (or 100 mL) of solvent, the substance is considered moderately soluble. Slide 5 Like Dissolves Like Fats Fats Benzene Benzene Steroids Steroids Hexane Hexane Waxes Waxes Toluene Toluene Inorganic Salts Water Water Sugars Sugars Small alcohols Small alcohols Acetic acid Acetic acid Polar and ionic solutes dissolve best in polar solvents Nonpolar solutes dissolve best in nonpolar solvents Slide 6 The polar charges on water molecules are attracted to the opposite charge on the ions in ionic compounds If this attraction causes the ions to separate (dissociate), then the ionic compound dissolves Ionic compounds that are soluble, always form ions in solution Slide 7 K 2 CrO 4 (aq) + Ba(NO 3 ) 2 (aq) Slide 8 Solubility of NaCl in Water Slide 9 An electrolyte is: A substance whose aqueous solution conducts an electric current Ionic compounds form electrolytes when they dissolve, because the ions separate and move around independently A nonelectrolyte is: A substance whose aqueous solution does not conduct an electric current Molecular compounds do not form electrolytes when they dissolve Electrolytes and Nonelectrolytes Slide 10 Electrolytes vs. Nonelectrolytes Slide 11 Solubility of Molecular Compounds in Water If we are comparing the water solubility of two similar molecules, the one with the higher percentage of the molecule that is polar (hydrophilic) is expected to have higher water solubility. We predict that the molecule with the higher percentage of its structure that is nonpolar (hydrophobic) to be less soluble in water. Slide 12 Hydrophobic and Hydrophilic Slide 13 Methamphetamine Slide 14 Triglycerides (Fats and Oils) Slide 15 Tristearin Slide 16 Tristearin Line Drawing Slide 17 Making Soap Slide 18 Soap and Detergent Slide 19 Cleaning Greasy Dishes Slide 20 Oil Droplets and Soap or Detergent Slide 21 Solubility Trends The solubility of MOST solids increases with temperature. The rate at which solids dissolve increases with increasing surface area of the solid. The solubility of gases decreases with increases in temperature. The solubility of gases increases with the pressure above the solution. Slide 22 Using Coffee Cold Warm Hot Cold Warm Hot Water Water Water Water Water Water Slide 23 Solubility and Temperature Temperature affects how much solute dissolves (solubility) Temperature affects how quickly a solute dissolves (rate) Increasing the temperature not only increases the amount of solute that will dissolve but also increases the rate at which the solute will dissolve Slide 24 Therefore Solids tend to dissolve best when: o Heated o Stirred o Ground into small particles Gases tend to dissolve best when: o The solution is cold o Pressure is high Slide 25 Solubility Chart

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