Chemistry Test 4 Review Solutions and Solubility

Solutions and Solubility Unit Test Review 8.2 Solutions and their Characteristics - Homogeneous mixture: a mixture that has the same proportions of its components throughout any given sample (uniform), only one phase is visible - Heterogeneous mixture: a mixture that contains 2+ phases - Solute: what is dissolved - Solvent: the medium in which the solute is dissolved - Solution: solute + solvent - Aqueous solution: a solution in which water is the solvent - Concentrated: a solution with a relatively large quantity of solute dissolved per unit volume of solution - Dilute: a solution with a relatively small quantity of solute dissolved per unit volume of solution 8.3 The Dissolving Process - How do ionic and molecular compounds dissolve? - Ionic compounds: Ionic bonds are very strong and hard to break. Water is very polar though. Negative ions of the waters are able to pull on the positive ions of the ionic compound and surround it with a layer of water (hydration). The positive ends of the water molecules pull on the anions of the crystal. They separate (dissociation). - Molecular compounds: This will vary. Refer to “like dissolves like” concept. Remember: polarity is determined by the electronegativity differences and symmetry of the molecules (lone pairs). Water must be more polar than the compound. Know the terms hydration, dissociation, miscible, immiscible, etc. - Hydration: the process in which ions are surrounded by water molecules - Dissociation: the separation of individual ions from an ionic compound as it dissolves in water - Miscible: liquids that mix with each other in all proportions to form a solution - Immiscible: liquids that don’t readily mix - - What role do intermolecular forces play in the process of dissolving? - The stronger the intermolecular forces, the stronger the bonds within the compound, which means they are able to pull away ions from an ionic compound better Know the concept ‘like dissolves like’ (polar compounds dissolve in polar solutions, non-polar compounds dissolve in non-polar solutions) Know what surfactants/detergents are and how they work - A compound that reduces the surface tension of the solvent. Has a hydrophilic (polar) and hydrophobic end (non-polar). Nonpolar end attaches to oil and lifts it off, which then dissolves bc of polar end. 8.5 Solubility and Saturation - - Know the terms saturated, unsaturated and supersaturated - Saturated: a solution that contains the maximum quantity of solute at given temperatures and pressure - Undersaturated: a solution that contains less than the maximum quantity of solute at given temperatures and pressure - Supersaturated: a solution that contains more than the maximum quantity of solute at given temperatures and pressure Know how to read and understand a solubility curve Know how temperature affects the solubility of both solids and gases - Solid: solubility increases as temperature increases - Gases: solubility decreases as temperature increases 8.6/8.8 Solution Concentration - Amount Concentration - What unit is used for amount concentration? mol/L - Know the formula (c = n/v) and be able to perform calculations involving mass and volume (Practice: pg 400, #1, 2 // pg 402 #2, 3, 5, 9, 10) - Know the three different types of percentage concentration - Know the formulas for each of these and be able to use them in calculations. - Cv/v = Vsolute/Vsolution x 100% - Cm/v = msolute/Vsolution x 100% (in g/mL) - Cm/m = msolute/msolution x 100% - Very low concentrations/dilute solutions - ppm (106) , ppb (109) , ppt (1012) *** msolute/msolution - Know the units used for each of these and be able to perform calculations. - Know how to calculate quantities for making standard solutions by weighing solids 8.7 Making Dilutions - Making solutions - CcVc = CdVd - Know how to use the above formula to calculate quantities for making solutions by diluting a standard solution 9.1 Reactions in Solution - Know how to write total ionic equations and net ionic equations 1. Write the total ionic equation (separate aqueous ions, leave solids, liquids, gases alone) 2. Identify spectator ions (ions that don’t change throughout the reaction) 3. Write the net ionic equation (exclude spectator ions) 9.5 Stoichiometry of Solutions - Know how to perform the various types of solution stoichiometry calculations performed in class using full, balanced chemical equations - Remember how to do limiting reagents - Same idea as any other calculation, BUT, if doing calculations of ions, remember to use the subscript from compound as coefficient of the ion. MOLE RATIO APPLIES TO IONS: 10.1 Properties of Acids and Bases - What are acid-base indicators? - Typically solution colour indicators that tell you whether a solution is a base, or acid (i.e phenolphthalein turns pink for bases) - How can we determine whether a solution is neutral, acidic, or basic? - pH indicator test - pH = −log[H+], where H+ is in mol/L 10.2 Theoretical Acid-Base Definitions - Know the PowerPoint slides - Know the general properties of acids and bases - Know the characteristics of the Arrhenius and Bronsted Lowry definitions of acids and bases - Know the difference between a strong acid and a weak acid - Understand conjugate acid-base pairs