Organic Chemistry States of Matter

American Chemical Society (A.C.S) General Chemistry Exam 70 multiple choice questions, 110 minute Bring a Scantron, calculator and pencil(s) Preview for ACS-Standardized final Exam 1. 70 Multiple Choice questions, 110 minute. Bring a Scantron, calculator and pencil(s) 2. Scoring is based on correct answers. If you don’t know the answer, it pays to guess. It especially pays to rule out one or two obviously incorrect answers, even if you aren’t sure about which answer is actually correct. 3. Total time will be 110 minutes. This means you have 1 minute and 34 seconds per question. Time management is important, but most students complete in time. A more common error than going too slow is to work too fast, hurrying early in the test and not taking enough time to carefully read through the questions and look at all the answers. I think it is foolish to every leave before time expires on a multiple choice exam, because the time wasted by leaving early will usually be enough to have rechecked several guess problems and to have eliminated some impossible answers. If time permits, you would like to answer the problem on your own, and then see if your answer matches on of the listed alternatives. 4. There are likely going to be questions that you do not know. While you will not get them all right (a student can totally guess on 15 questions and still get an A!), the key is that you get at least some of the questions absolutely certain, and can make an educated guess on a reasonable portion of the rest. 5. Scores, percentiles, and Grades. The statistical analysis is based on the performance of 1,000 students. Shown below are some raw scores with the corresponding nation percentiles, and the grade that will correspond. RAW Percentile Grade RAW Percentile Grade RAW Percentile Grade Score Rank Recorded Score Rank Recorded Score Rank Recorded 10 0% 15 33 31% 75 52 90% 100 17 2% 20 34 34% 75 53 92% 100 (17.5 should be the statistically 35 38% 75 54 93% 100 average score of a monkey guessing!) 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 3% 3% 4% 5% 6% 7% 9% 10% 12% 14% 16% 19% 22% 24% 28% 25 30 35 40 45 50 55 55 60 60 65 65 70 70 70 36 41% 80 37 45% 80 38 49% 80 National Average is 38.3 39 53% 80 40 56% 80 41 60% 85 42 64% 85 43 67% 85 44 71% 90 45 74% 90 46 77% 90 47 80% 90 48 82% 95 49 84% 95 50 87% 95 51 89% 95 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 94% 95% 96% 97% 98% 98% 98% 99% 99% 99% 99% 100% 100% 100% 100% 100% 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 TOPICS THAT FREQUENTY APPEAR ON THE ACS STANDARDIZED TEST States of matter Ideal Gas Law: pV=nRT, pM=dRT, deviations from ideal (high P, low T) Ionic solids: simple cubic, face centered cubic, body centered cubic Phase diagrams: Pressure versus temperature Intermolecular Forces: ion-diope, hydrogen bonding, etc. II. Stoichiometry and Thermochemistry Hess’s Law and Enthalpy: “standard states” have ΔHf0= 0 Percent composition: %C, %H, etc. Combustion analysis Limiting Reactants Stoichiometry III. Atomic Structure and periodicity Oxidation states of “main group” elements (Li, Be, B, etc) Oxidation numbers Electron configurations and relation to groups on periodic table (ns2np5=halogens) Periodic trends: Electronegativity, atomic radii Nuclear chemistry: Mass number, atomic number IV. Molecular Structure Modes of bonding: ionic, covalent (both polar and non-polar) Lewis Dot, VSEPR, polarity, bond angles, resonance structures V. Solutions Molarity: mol solute/L solution; also dilution (M1V1=M2V2) Net ionic equations Percent dissociation in water (electrolyte strength) Molality: mol solute/kg solvent Freezing point depression/boiling point elevation ΔTf=Kfm VI. Acids, Bases and Ionic Equilibria Know the “spectator” ions in acid/base reaction: Na+, K+, Cl-, NO3- etc. Know general reactions for acid base (strong acid+ strong base, SA + WB, WA+SB) Equivalence point, finding unknown concentrations Buffers: What makes a buffer, what a buffer is, etc. pH: calculate pH of weak acids or reactions prior to the end point (strong acid+ strong base, SA + WB, WA+SB) VII. Chemical Equilibrium – Molecular General equilibrium expressions: know how to find K LeChatlier’s principle: effect of heat upon endothermic/exothermic reactions Precipitation reactions VIII. Kinetics Rate of disappearance, rate of formation Effect of catalysis Rate laws and ahlf life from experimental data Energy of activation IX. Thermodynamics Enthalpy, entropy, free energy Relation of free energy to equilibrium constant and Eo I. X. Electrochemistry Calculations of E values for electrochemical cells Balancing redox reactions Definitions of oxidized and reduced XI. Descriptive Chemistry Nuclear chemistry: Balancing reactions, alpha particles, beta particles, positrons, etc. Elemental reactivity: with water, oxygen, acids Coordination chemistry: determine coordination number around central metal Ionization energy periodic trend General nomenclature X. Laboratory: General familiarity with basic techniques and appearance of common substances