Download Final Exam, Chem 111 2012 Study Guide (labs)

RATES OF REACTIONS/A CLOCK REACTION
1. Understand how the Clock Reaction works.
a. Write the chemical equation for the reaction studied in this experiment.
b. Write chemical equations corresponding to the “clock” part of the experiment
(i.e., the part that includes thiosulfate and starch).
c. Explain why thiosulfate does not appear in the rate law for this reaction.
d. Predict whether Δt will be bigger or smaller when the amount of thiosulfate is
increased.
e. Calculate reagent concentrations from given stock concentrations.
2. Understand how rate laws and associated parameters are deduced from initial rate
data.
a. Given a set of experimentally-determined initial rates, infer a rate law.
b. Given a rate law, predict relative changes in reaction rates when initial
concentrations of reagents are doubled, halved, etc.
c. Given a rate and a set of concentrations, calculate a rate constant.
d. Explain the idea of stoichiometric equivalence, with examples.
RATES OF REACTIONS/A CLOCK REACTION:
ENERGY OF ACTIVATION
1. Be familiar with the methods and results of Arrhenius analysis.
a. Demonstrate appropriate techniques for conducting variable-temperature
experiments.
b. State the axes and expected appearance of an Arrhenius plot.
c. Produce an Arrhenius plot from temperature and rate constant data.
d. Given an Arrhenius plot, use trendline parameterizations to deduce the energy of
activation (Ea, kJ/mol) and pre-exponential factor (A).
TITRATION OF CONSUMER PRODUCTS
1. Be familiar with methods of titration analysis.
a. From the results of a trial titration, calculate the amount of analyte required to
produce a titration of a desired volume (e.g., 30 mL of titrant).
b. Infer the pKa of an unknown acid analyte from a given titration curve.
c. Infer the amount (moles) of analyte from a given titration curve.
d. Infer the % by weight of active ingredient in a given sample, from titration results.
BUFFER CAPACITY AND POLYPROTIC ACIDS
1. Be familiar with the preparation of buffers.
a. Demonstrate how to make a buffer of desired pH from given stock solutions.
2. Be familiar with the chemical reactions associated with titrations of polyprotic acids.
a. Identify predominant forms of a substance (e.g., H2A, HA-, A2-) at given points in
the titration of a polyprotic acid with a strong base.
b. Write titration reactions appropriate for given intervals in a titration of a
polyprotic acid with a strong base.
ELECTROCHEMISTRY
1. Be familiar with the construction and properties of electrochemical cells.
a. Demonstrate construction of a working electrochemical cell.
b. From measurements, rank half-cells in order of increasing half-cell reduction
potential.
c. Convert measured half-cell reduction potentials to values relative to S.H.E.
d. Predict new cell potentials from measurements of half-cell potentials.
ORGANIC NOMENCLATURE
1. Be familiar with the structure and nomenclature of organic compounds.
a. Explain the origin of steric repulsion, with examples (e.g., eclipsed vs staggered)
b. Explain how to tell when two structures are different conformations of the same
molecule, vs when they are different constitutional isomers.
c. Draw distinct constitutional isomers for given alkanes and alkenes.
d. Explain what a methyl group is.
e. Explain what the prefixes “neo”, “iso” and “n-” mean when describing alkanes.
f. Explain what is meant by mono- and di-substituted cycloalkanes.
g. Identify and name distinct cis-trans stereoisomers in alkenes and cycloalkanes.
h. Designate given amines as primary, secondary, or tertiary.
i. Make line drawings of given carboxylic acids (e.g., ethanoic acid).
j. Describe the characteristic functional group of each family of organic compounds,
and supply the common name of given examples of each. For carboxylic acids,
also supply the IUPAC names.
SYNTHESIS OF OIL OF WINTERGREEN FROM ASPIRIN®
PART 1: HYDROLYSIS OF ASPIRIN
1. Be familiar with organic synthesis procedures.
a. Sketch a vacuum filtration apparatus.
b. Demonstrate proficiency in carrying out vacuum filtration.
c. Describe key safety considerations associated with saponification (and other
work-up procedures associated with the synthesis of an carboxylic acid).
2. Be familiar with organic synthesis strategies associated with saponification.
a. Define saponification, and explain how it is different from generic hydrolysis.
b. For a given ester, write a balanced chemical equation for its saponification.
c. Find pKa values for a given polyprotic acid in the literature, and use them to
predict the predominant form of the acid.
d. Write IUPAC names for given esters and carboxylic acids.
e. Explain the difference between an alcohol and a phenol.
SYNTHESIS OF OIL OF WINTERGREEN FROM ASPIRIN®
PART 2: METHYL SALICYLATE FROM SALICYLIC ACID
1. Be familiar with organic synthesis procedures.
a. Describe the components of an acid reflux apparatus.
b. Demonstrate proficiency in carrying out an acid reflux experiment.
c. Describe the layering one expects to find in a separatory funnel with an aqueous
phase and a denser organic phase.
d. Demonstrate proficiency in carrying out an aqueous/organic extraction.
2. Be familiar with organic synthesis strategies.
a. Write a balanced chemical equation for acid-catalyzed esterification.
b. Explain the purpose of adding excess methanol in the esterification step.
c. Describe the chemical principles underlying aqueous/organic extraction, and
explain why, in the extraction of methyl salicylate at the end of this procedure, a
weak base (sodium bicarbonate) is used instead of a strong base.
PEPTIDE MODELS
1. Become familiar with structural properties of amino acids.
a. Make line diagrams of alanine, glycine, serine, cysteine, aspartic acid, lysine, and
histidine, showing the predominant form as a function of pH.
b. Identify the α-carbon and carbonyl carbon in a given amino acid.
c. State whether a given amino acid is nonpolar neutral, polar neutral, etc.
2. Become familiar with structural properties of peptides & proteins.
a. Identify the locations of peptide bonds, amide planes, bridge carbons, R-groups,
and N- and C-terminus, in a given peptide model.
b. Identify whether a given peptide bond is “trans” or “cis” with respect to the
peptide backbone.
c. Identify the bonds to a given bridge carbon corresponding to rotations φ and ψ.
d. Describe H-bonding interactions that occur in an α-helix.
ETHANOL FROM SUCROSE
1. Become familiar with practical aspects of fermentation and distillation.
a. Demonstrate proper set-up of a fermentation procedure.
b. Carry out calculations related to the volume of gas produced during fermentation.
c. Describe the components of a fractional distillation column.
d. Demonstrate proper set-up of a fractional distillation column.
e. Describe the architecture of a gas chromatograph.
f. Determine the % composition of ethanol in an ethanol/water solution using gas
chromatography.