Chemistry: Matter as Aqueous Solutions

Matter as Aqueous Solutions

• Key Vocabulary: Solution, solute, solvent, homogeneous, heterogeneous, saturated solution, unsaturated solution, supersaturated solution, solubility, electrolyte, nonelectrolyte
• Predicting Precipitates: Nitrate, ammonium, potassium, and sodium salts are generally water-soluble. Use this knowledge to predict the formation of precipitates.
• Precipitation Reactions: Write balanced chemical equations (BCE), complete ionic equations (CIE), and net ionic equations (NIE) for reactions in water. Be able to predict products and identify spectator ions.
• Water-Solvent Interactions: "Like dissolves like" means polar solvents dissolve polar solutes, and nonpolar solvents dissolve nonpolar solutes. Electrostatic attraction is the driving force.
• Effect of Temperature/Pressure on Solubility: Temperature and pressure affect the solubility of solids and gases in water. Effects vary depending on the solid or gas.
• Electrolytes vs. Nonelectrolytes: Electrolytes dissolve to form ions in solution and conduct electricity, while nonelectrolytes do not. Examples are crucial for understanding this distinction.
• Solution Stoichiometry: Calculate molarity, volume, moles, and grams of solute. Understand solution preparation and dilution.
• Solubility Curves: Interpret solubility curves to identify unsaturated, saturated, and supersaturated solutions. Perform calculations based on the given curves.

Thermochemistry

• Temperature: Understand the concept of temperature.
• Calorimetry: Understand calorimetry techniques and how heat transfer works in different situations (isolated, no heat exchange etc). Solve various problems using calorimetric equations
• Specific Heat Determination: Determine the specific heat of a metal using experimental data.
• Enthalpy (ΔH): Understand the concept of enthalpy.
• Systems (Open, Closed, Isolated): Define different types of systems.
• Systems vs. Surroundings: Distinguish between systems and surroundings in thermochemical processes.
• Endothermic vs. Exothermic: Differences in heat flow in endothermic and exothermic processes.
• Heat Sign Convention (q): Understand the meaning of positive and negative heat values.
• Phase Changes: Define all types of phase changes (solid to liquid, liquid to gas etc). Determine if the phase change is endothermic or exothermic.
• States of Matter (Solids, Liquids, Gases): Analyze the similarities and differences in the different physical states of matter (shape, volume, particle speed)
• Heating/Cooling Curves: Sketch and interpret heating and cooling curves identifying temperature changes.
• Thermochemical Equations: Understand how heat (enthalpy change ΔH) may be represented within chemical reactions in terms of chemical equations including whether ΔH is presented within or outside of equation. Examples are needed for understanding.
• Standard Molar Enthalpy of Solution (ΔH solution): Determine ΔH solution using experimental data.
• Hess's Law: Use Hess's Law, ΔH formation, and bond energies to calculate ΔH reaction.
• Bond Energies Accuracy: Explain why bond energies are less accurate for calculating ΔH.

Chemical Kinetics and Chemical Equilibrium

• Collision Theory: State the colliding particles theory- what conditions need to be met for a reaction to occur.
• Potential Energy Diagrams: Draw and interpret potential energy diagrams for exothermic and endothermic reactions. Explain how diagrams are used in different situations
• Activation Energy: How catalysts affect activation energy.
• Homogeneous vs. Heterogeneous Catalysts: Define and differentiate between homogeneous and heterogeneous catalysts.
• Activated Complex: Describe the activated complex.
• Reaction Mechanisms: Identify intermediates, catalysts, the overall reaction.
• Factors Affecting Reaction Rate: Explain, in details , how the following factors affect reaction rate referring to Collision Theory: temperature, concentration, surface area, and catalysts.
• Chemical Equilibrium: Define the conditions for chemical equilibrium.
• Equilibrium Constant (Kc): Express equilibrium constant for reactions, focusing on gases and aqueous solutions. Explain the significance of the Kc value (e.g., favoring products or favoring reactants)
• Reaction Quotient (Qc): Express reaction quotient for reactions, focusing on gases and aqueous solutions,. Explain the significance comparing Qc to Kc in terms of direction of reaction.
• R.I.C.E. Tables: Solve simplified equilibrium problems using R.I.C.E. tables. Be aware of approximation rules for avoiding quadratic equations.
• LeChâtelier's Principle: Explain Le Chatelier's Principle and how various stressors (concentration, temperature, pressure/volume) affect equilibrium position. State how catalyst affects system

Acids and Bases

• Physical Properties: Describe physical properties of acids and bases.
• Reactions of Acids/Bases: Describe reactions when acids/bases react with active metals and carbonates.
• Arrhenius Theory: Acids produce H+ ions in water; bases produce OH- ions in water.
• Brønsted-Lowry Theory: Acids are proton (H+) donors, and bases are proton acceptors.
• Acid-Base Conjugate Pairs: Identify acid-conjugate base and base-conjugate acid pairs.
• Acid-Base Properties of Water: Understand autoionization of water and the ion product constant (Kw).
• pH/pOH Formulas: Know how to use formulas for pH, pOH, [H3O+], [OH-], and Kw.
• pH Scale: Understand the pH scale, relationship between pH and acidity, and relate it to temperature.
• Titration Calculations: Perform titration calculations.
• Acid-Base Indicators: Choose appropriate indicators for titrations.
• Electrolytes (Strong/Weak): Define strong and weak electrolytes and give examples of each based on the given theories.
• Acid Strength (Ka): Relate Ka to acid strength.
• Strong Acids: Recall six strong acids and their formulas. Strong bases are usually group 1 or 2 metal + OH-.
• Weak Acid pH Calculation: Calculate the pH of a weak acid solution given its initial concentration and Ka.
• Percent Acid Dissociation: Calculate percent acid dissociation

Electrochemistry

• Redox Reactions (Oxidation & Reduction): Define oxidation and reduction in terms of electron loss or gain (LEO the lion goes GER).
• Oxidizing/Reducing Agents: Identify oxidizing and reducing agents in redox reactions.
• Oxidation Numbers: Assigned oxidation numbers to compounds, molecules, and ions.
• Balancing Redox Equations (Acidic Medium): Balance redox reactions in acidic medium using the half-reaction method.
• Galvanic Cells: Identify anode, cathode, salt bridge, external circuit, and internal circuit
• Cell Notation: Draw cell diagrams.
• Standard Reduction Potentials: Use standard reduction potentials to calculate standard cell potential. Avoid inverting sign errors.
• Spontaneous Reactions: Recognize that redox reactions that have a positive reduction potential are spontaneous.