Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chemistry 107 - Fall 2009

Final Exam Study Guide

2009 Version

The Final Exam will be Comprehensive! Approximately 1/2 will focus on recent material and those things you need to know to understand the latest material, while about 1/2 will be on problems/materials similar to what has been seen on previous exams.

Approximately 1/4 of the exam will be multiple choice, the remainder will be similar to previous exams and the example on the web.

Review: Study Guides I & II; Quizzes and problem sets since Exam I & II. Review nomenclature so that you can read questions and understand them.

Solutions and Colligative Properties

Define/describe: solution, salt, solvent, solute, saturated solution, unsaturated solution, super saturated solution, mass %, ppm, ppb, molarity (M = mol/L), molality (m = mol/kg), mole fraction (X = moles/total moles), neutralization, equivalent (in chemical reactions). Why do some substances dissolve in each other? Why do others not? ("Like Dissolves Like"). Be able to solve problems involving concentrations as we have seen in class and on the quizzes: find mass %, molarity, molality, mole fraction of solutions given their components. Be able to find concentrations of solutions after dilution or mixing with other components. Be able to do problems in homework. How does solubility vary with temperature? Why? How does the solubility of gases vary with pressure? Explain this variation. Colligative properties: Ideal solution. What are colligative properties? What do they depend on? (only the number or concentration, not on the type, of particles.) Be able to solve problems involving the colligative properties we have discussed (boiling point elevation (T = km, where m = molality and k = the boiling point constant), freezing point depression (T = - k'm, where m = molality and k' = the freezing point constant), osmotic pressure (PiV= nRT; Pi= MRT), vapor pressure lowering - Raoult's Law (P = XP°)). Colligative Properties Module

(properties which . Be able to solve problems for freezing point depression (T = - k'm, where m = molality and k = the freezing point constant).

Rates of Reaction (Kinetics)

What are the basic premises of Collision Theory? Why are three body termolecular and higher reactions rare? What three factors did we discuss as affecting the rates of reactions (collision frequency, activation energy {Eact}, and orientation). How are these factors related to measurable macroscopic properties (concentration and temperature). Be able to draw and interpret Reaction Progress (or Reaction Coordinate) Chemical Equilibria Module, pt1. Note how these diagrams indicate/reflect changes in rate (kinetics) and completion of reaction(equilibrium).

Equilibrium

Define/describe: Equilibrium, Le Chatelier's Principle, Mass Action Expression (Q), Equilibrium Expression (Keq or K), acid and base dissociation equilibria (Ka & Kb). Be able to do equilibrium problems as we have seen in class and on homework. Be able to write balanced chemical equations, equilibrium expression (Keq = ([P][Q[)/([A][B]), for A + B equilibrium double arrow P + Q), and solve for unknown quantities. Remember special expressions for ion product of water (Kw = [H+][OH-]) & solubility product (Ksp = [A+][B-] for AB(s) equilibrium double arrow A+ + B-). How would pressure affect gaseous equilibria? How does temperature affect equilibria? Chemical Equilibria Module, pt2 , Dissociation Equilibria Module

Acids, Bases, and Salts

Define/describe: Arrhenius acid model, Brønsted-Lowry acid theory (acid = proton donor, base = proton acceptor, conjugate acid/base pair), hydronium ion, salt, electrolyte, non electrolyte, strong acid/base (100% dissociated when < 1M), strong electrolyte, weak acid/base (less than 100% dissociated when < 1M), weak electrolyte, neutralization, titration, Kw (Kw = 1.0 x 10-14 = [H+][OH-])

pH and Buffers

pH, pKa, pOH, buffer. Be able to calculate [H+] & [OH-] given pH & pOH, and vice versa. Note that acid/base dissociation reactions and buffers are equilibrium systems. Be able to find [H+], [OH-], pH, & pOH for weak acid or weak base solutions. Be able to use the Henderson-Hasselbalch equation and/or the equilibrium expression to determine the pH of a buffer and/or the ratios of acid:salt in a buffer of a given pH. pH & Bufffers Module

Oxidation/Reduction Chemistry

Be able to determine oxidation numbers for any atom in a compound using the rules we have used in class. Note the oxidation number of a metal is the same as the Roman numeral used in nomenclature, e.g. for Mn(VI) manganese has an oxidation number (or oxidation state) of 6; for Fe(III) iron has an oxidation number of 3. Oxidation Numbers Module

Be able to balance simple equations by inspection such as we have done in class. Be able to identify redox reactions. Be able to identify oxidant and reductant, oxidizer and reducer, oxidized and reduced substances in chemical reactions. Be able to balance redox equations using the half-reaction method, as in the lecture example & Redox Balancing Supplemental Study Module.

Memorize/Know

The gas constant, R= 0.0821. Avogadro's number = 6.02 x 1023, volume of a gas at STP (what is STP?). Mass of one amu in grams (one gram divided by Avogadro's number). Values for: h (Plank's constant) & c (speed of light). The electronegativities of the Period 2 elements. Conversions within the Metric System. Temperature at absolute zero in °C and K. Freeezing and boiling points of water in °C and K. One atm = 760 mmHg.

You may bring ONE HALF of a sheet of 8.5x11 (8.5"x5.5") paper with formulae etc. on both sides

as a "cheat sheet" for the final.

You should be careful and thorough in designing and creating this sheet.

Remember it is for reference and insurance, the less you rely on it the better off you will be!

 

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Last modified 10 December 2009