CHM 152 Final Exam Review

Transcription

1 CHM 152 Final Exam Review Kinetics Chapter 12 End-of-Chapter Suggested problems: 1, 2, 3, 4, 6, 7, 9, 11, 13, 14, 15, 17, 19, 21, 25, 29, 31, 33 (graphing), 37, 39, 41, 47, 51, 53, 57, 63, 67, 68, 69, 70, 71, 72, 73, 77, 79, 81, 83, 85 List the factors that can affect the rates of a reaction (concentration, temperature, catalyst, etc.) List the two components of Collision Theory that will result in a successful collision. Define activation energy (E a ). Draw a graph of a reaction pathway versus energy. Label E a and ΔH. Also be able to identify a value of E a and ΔH (with appropriate sign). Write the general equation for the rate expression of a reaction. If given the rate of one substance, be able to calculate the rate of another substance in a reaction. Write the general form of an equation s rate law. Identify how to determine the order of a reactant using a table of concentrations and initial rates. Be able to calculate the rate constant, k, for a rate law and determine the units of k. Be able to identify the overall order of a reaction. Identify the functions of concentrations used in integrated rate laws to graph a linear plot for zero, first, and second order reactions. Use Integrated Rate Laws for first and second order reactions to calculate 1) the amount of reactant left after time or 2) how long it takes a reactant to reach a certain concentration. Use half life equations to calculate k for first or second order reactions. Describe the relationship between temperature and rate constant. Be able to use the Arrhenius equation to solve for activation energy or rate constant. o ln k = -(E a / R)(1 / T) + ln A is used for 4 or more data points. Slope (m) = -E a /R. o ln (k 1 / k 2 ) = -(E a /R) (1/T 1 1/T 2 ) Define reaction mechanism. Identify how the molecularity of an elementary step is determined. Be able to write the net/overall equation for a mechanism. Be able to identify the rate-determining step. Label and identify an intermediate and catalyst for a series of elementary steps. Be able to write the rate law for the overall equation when the first step is slow. Be able to identify which step is rate determining when given the rate law for the overall equation. Explain the difference between a homogeneous and a heterogeneous catalyst. Equilibrium Chapter 13 End-of-Chapter Suggested problems: 1, 5, 7, 9, 13, 15, 17, 19, 21, 23, 25, 31, 32, 33, 34, 37, 39, 41, 43, 45, 49, 53, 55, 57, 59, 61, 63, 65, 73, 75, 79, 80, 82, 88, 94, 95 Explain why equilibrium is considered to be a dynamic state. Describe how to write the equilibrium expressions for a given equation. Identify what physical states can be included in a K c expression; in a K p expression. Define heterogenous and homogeneous equilibria. Be able to write and use the equation relating K c to K p. Note the R value used and how to calculate Δn. Be able to interpret what a large (and a small) K value indicates about an equilibrium system.

2 Be able to calculate an equilibrium constant given equilibrium concentrations or pressures. Identify how to determine whether or not a system is at equilibrium (K) and determine in which direction a reaction must shift (Q < K or Q > K) in order to reach equilibrium. Identify how an equilibrium constant will change when equations are modified (e.g., an equation is reversed or two equations are added together) Given an equilibrium constant for a reaction, be able to solve for all equilibrium concentrations (using method of perfect squares, assuming x is small, or quadratic). Define Le Chatelier s Principle. Be able to identify in which direction a system will shift when the following stresses are applied to a system. o Concentration of a reactant is increased o Concentration of a product is increased o Concentration of a reactant is decreased o Concentration of a product is decreased o Volume is increased (or decreased) look at number of moles of gas in reaction o Pressure is increased (or decreased) look at number of moles of gas in reaction o Temperature is raised (or lowered) look at whether the reaction is endo or exothermic Acids, Bases, and Salts Chapter 14 End-of-Chapter Suggested problems: 1, 2, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 26, 27, 31, 32, 33, 35, 37, 39, 41, 43, 47, 49, 51, 53, 55, 57, 59, 61, 65, 67, 69, 71, 75, 77, 79, 81 Understand, in general, the definitions of Arrhenius, Brønsted-Lowry, and Lewis acids and bases (emphasis on Brønsted-Lowry). Know the seven strong acids. Know the strong bases. Know what makes an acid/base strong or weak. Be able to recognize the many nitrogen-containing bases that have a similar structure as NH3. Assume that any acid not on the list of the seven strong acids is a weak acid. Understand the relationships between ph, poh, [H 3 O + ], [OH - ] in aqueous solutions. Be able to calculate these values. Calculate the ph of a strong acid solution Calculate the ph of a weak acid solution Understand the relationship between weak acid strength and K a (or pk a ). Understand the relationship between weak base strength and K b (or pk b ). Determine and identify Brønsted-Lowry conjugate acid base pairs. Understand the relationship between conjugate acid/base pairs. Understand the relationships bet K a /K b and pk a /pk b of conjugate acid base pairs. Know the relationships between the strength of an acid and its conjugate base or vise versa. Know the relationship between Ka and Kb (and pka and pkb) of conjugate acid/base paris. Determine which way an acid/base reaction is most likely to proceed given Ka s, Kb s, pka s, pkb s, etc. (or, if given a list of relative strengths of acids and bases). Understand how molecular structure affects acid strength. Know the meaning of polyprotic acids. Understand the trend of Ka s for successive dissociation of protons in polyprotic acids Calculate the % dissociation/ionization of any week acid.

3 Understand how the % dissociation changes with changing acid concentration. Determine if a salt is acidic, basic, or neutral. Buffers, Titrations, and Solubility Equilibria Chapter 15 End-of-Chapter Suggested problems: Chapter 14: 87, 89, 93, 95, 97, 101, 103, 105, 107, 109, 115; Chapter 15: 1, 3, 4, 5, 7, 8, 9, 10, 11, 12, 13, 15, 20, 21, 25, 27, 29, 31, 40, 45, 47, 59, 62 Understand the common-ion effect and how it affects % dissociation/ionization. Understand what types of substances are in buffers solutions. Understand which chemical species reacts with a strong acid or strong base when added to a buffer solution. Understand which chemical species should be in solution after adding different amounts of strong acid or strong base. Calculate the ph of a buffer solution using the H-H formula. Calculate the ph of a buffer solution after adding a strong acid or base using change tables, etc. Recognize and be able to label acid/base titration curves (equivalence point, etc.). Understand which chemical species should be in solution at various points along an acid/base titration curve. Calculate the ph during various points of an acid/base titration using change tables, etc. (before beginning titration, during titration, equivalence point, past equivalence point). Calculate the molar solubility of a sparingly soluble salt given K sp. Calculate K sp knowing equilibrium concentrations of a sparingly soluble salt. Know that factors that affect the solubility of sparingly soluble salts (common-ion effect, basic solutions, acidic solutions, complex ion formation, etc.) Understand how chemists can use different solubilities of sparingly soluble salts to separate ions (i.e. precipitate some ions while leave others in solution). Determine which insoluble salt should form first based on K sp s. Determine whether a sparingly soluble salt will precipitate given concentrations of ions in solution using K sp vs. Q sp Calculate the minimum concentration an ion must have before a sparingly soluble salt will precipitate (given K sp and concentration of various other ions in solution). Thermodynamics Chapter 16 End-of-Chapter Suggested problems: 1, 2, 3, 7, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 25, 26, 29, 31, 32, 33, 35, 37, 38, 39, 41, 43, 45, 46, 48, 52, 58, 59, 61, 65 State the first 3 laws of thermodynamics. Identify nonspontaneous vs. spontaneous processes. What does entropy measure? What is the order of entropy values (from smallest to largest) for solids, liquids, and gases? Predict the sign of the entropy change for a given process. Describe how the entropy of a substance changes with temperature. Calculate the standard entropy change for a reaction from provided data. How is standard state defined? Identify elements in their correct standard state where ΔH! f = 0 & ΔG! f = 0. Identify the chemical reaction associated with the standard free energy of formation for a compound. How do ΔH and ΔS combine to determine the spontaneity of a system?

4 Calculate the standard change in enthalpy (ΔH ) or free energy (ΔG ) for a reaction from provided data. Calculate the change in free energy from provided enthalpy and entropy values: ΔG = ΔH-TΔS. Identify whether a reaction is spontaneous or nonspontaneous from its ΔG value. Calculate the temperature at which a process becomes spontaneous/nonspontaneous given the values for ΔH and ΔS. Predict how ΔG will change with temperature given the signs for ΔH and ΔS. Calculate ΔG under nonstandard conditions: ΔG = ΔG + RTlnQ Calculate ΔG from K and perform the reverse operation: ΔG = -RTlnK Relate the ΔG value (+, - or 0) to the magnitude of the K value. Identify the free energy curves for ΔG > 0 and ΔG < 0. Electrochemistry Chapter 17 End-of-Chapter Suggested problems: 3, 4, 7, 9, 12, 13, 14, 15, 18, 19, 20, 23, 25, 27, 29, 30, 40, 42, 48, 49, 50 What is oxidation? What is reduction? How can you tell if something has been oxidized or reduced? How do you determine the oxidation number for an atom in an ionic compound? How do you determine the oxidation number for an atom in a molecule? When is an oxidation number equal to zero? What is an oxidizing agent and how do you determine the oxidizing agent from a balanced equation? What is a reducing agent and how do you determine the reducing agent from a balanced equation? Define the term galvanic cell. At which electrode in a galvanic cell does oxidation occur? What is the half reaction at this electrode? At which electrode in a galvanic cell does reduction occur? What is the half reaction at this electrode? Which electrode is gaining mass as the galvanic cell proceeds? Which electrode is losing mass as the galvanic cell proceeds? What is the purpose of the salt bridge? In which direction do the cations move in a salt bridge? The anions? How do the electrons move through a galvanic cell? What is meant by the term electroneutrality? How is it achieved in a galvanic cell? What does the term electromotive force, emf, refer to? What is the purpose of the SHE cell? What is meant by standard cell potential? What is the equation to find E o cell? How is a table of standard reduction potentials used to determine if a reaction is spontaneous? In writing shorthand notation, which electrode is on the left? What does the single vertical line represent? The double vertical line? How would the shorthand notation look for the single replacement reaction between solid zinc and cobalt (II) chloride? What does n represent in the equation ΔG o = - nfe o? What does F represent? How is E o cell related to the equilibrium constant K? What is the equation?

5 What is the Nernst equation and when is it applied to a problem? What is the equation that relates ΔG to ΔG o? Which one predicts spontaneity? How does an electrolytic cell differ from a galvanic cell? How is the quantitative amount of metal plated using electrolysis calculated? Nuclear Chemistry Chapter 21 End-of-Chapter Suggested problems: 1, 2, 3, 4, 5, 9, 10, 11, 13, 14, 15, 20, 21, 24, 27, 32, 33, 34, 36, 38, 45, 47 What is atomic notation? How is the mass number, A, identified for an isotope? How is the atomic number, Z, identified for an isotope? Identify these particles: alpha, beta, gamma, positron. How does nuclear transmutation occur? How does radioactive decay occur? How is a nuclear reaction balanced? What do the terms parent and daughter refer to in a radioactive decay reaction? Define fission and fusion. What is a radioactive decay series? What order in kinetics does radioactive decay obey? What set of equations are used to solve radioactive decay problems?