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APPENDIX 2 ASSESSMENT OF STUDENT LEARNING BROAD LEARNING GOALS I. Assessing Data Analysis Skills II. Assessing Molecular Representation III. Assessing Basic Measurement Skills IV. Assessing Knowledge of Intramolecular and Intermolecular Forces V. Recognizing the Properties of Substances: Structure/Property Correlations VI. Assessing Knowledge of Solutions VII. Assessing Understanding of How to Separate Compounds VIII. Assessing Understanding of Atomic, Molecular and Macromolecular Sizes. 1 APPENDIX 2 ASSESSMENT OF STUDENT LEARNING CONCEPTS ASSOCIATED WITH BROAD LEARNING GOALS I. Assessing Data Analysis Skills Concept Level Working knowledge of terminology and conventions (e.g., meaning of abscissa and ordinate, knowing that P vs. V means that P is the ordinate and V is the abscissa, meaning of positive and negative correlation, meaning of direct and inverse proportion) first-year Interpretation of graphed information first-year Elements of graphical style (e.g., maximizing use of graph area, choosing effective scales) first-year Use of graphing software (for obtaining quantitative information, although initial sketching of graphs by hand will be encouraged to maintain literacy) first-year Use of spreadsheet software first-year Sketching trendlines (estimating a best-fit curve by eye) first-year Working knowledge of basic statistics (mean, standard deviation, median, confidence limits, t-test) junior/senior Fitting trendlines (calculating a best-fit curve using least-square methods) junior/senior Evaluating goodness-of-fit of a trendline (proper use of correlation Coefficient, testing the null hypothesis that a fit parameter differs from zero) junior/senior Most of the concepts are listed at the first-year level not because students will have mastered them that soon but rather because they should be introduced to them in the first year. This notion is guided by graphs found in typical general chemistry books and by opportunities for graphical data analysis in the existing CHEM 2115 (Chem I Lab) experiments. Facility with any particular concept can be assessed at several levels of sophistication if the assessment instruments are designed well. 2 APPENDIX 2 II. Assessing Molecular Representation Concept Level Condensed formula Molecular formula Empirical formula Formulas of hydrates Formulas of ionic vs. covalent compounds Charges on ions Space filling models First-year (Chem I) Formulas showing all bonds (recognizing types of bonds) Partially condensed formulas Formulas of particles (these are not whole molecules, but parts of molecules) Functional group representation Line formulas Formulas showing stereochemistry (Fischer, Cram, Newman) Space filling models Formulas of coordination complexes First-year (Chem II & III) Chem IV & Inorganic Formulas of macromolecules 3-D representation of macromolecules Representation of enzyme active sites and protein binding sites Biochemistry Formulas of transient species for calculations of energy of different conformers P Chem. 3 APPENDIX 2 III. Assessing Basic Measurement Skills General Understanding that a measurement is subject to experimental error and therefore needs to be reproduced (Understanding systematic vs. random errors, propagation of error) Understanding how many digits are necessary to express the results of the measurement to the precision with which it was made. Understanding the difference between precision and accuracy Understanding what it means when asked to measure temperature to ± 0.1oC, or mass to ± 0.001 g. Understanding where the uncertainty lies in a measurement when reading scales. Understanding that a measurement is made up of a numerical value that is inextricably linked to a unit of measurement. Understanding the magnitude of an experimental value (e.g. checking that it makes sense). Experimental Knowing what glassware to use when asked to measure different volumes Knowing that glassware are calibrated differently to measure either approximate volumes or very specific volumes. Knowing the difference between glassware calibrated to contain or deliver volumes. Understanding the differences between the various balances and knowing which to use based on the mass to be measured. 4 APPENDIX 2 IV. Assessing Knowledge of Intramolecular and Intermolecular Forces Concept Level Electron-electron repulsion, electron-nucleus attraction and atomic structure first-year Electron-electron repulsion, molecular geometry, and polarity first-year Types of intermolecular forces (ion-ion, ion-dipole, dipole-dipole, induced dipole-dipole, induced dipole-induced-dipole) and their relative strengths first-year Intermolecular forces and states of matter first-year Intermolecular forces and trends in vapor pressure and boiling point first-year Hydrogen bonding and the anomalous properties of water first-year Intramolecular forces and conformational isomers sophomore Role of intramolecular hydrogen bonding in determining molecular structure (DNA double helix, α-helix) junior Hydrophobic effect junior Anomeric effect junior Molecular interpretation of nonideal gas properties junior/senior Relationship between molecular interactions and chromatography junior/senior 5 APPENDIX 2 V. Recognizing the Properties of Substances: Structure/Property Correlations Concept Level Recognizing the nature of a compound Ionic and covalent compounds Organometallic compounds Electron-deficient compounds Coordinate complexes Sugars amino acids and macromolecules Chem I, II Chem II, III, Inorg? Chem I, II, Inorg Inorganic Chem II, III, Biochem Recognizing physical properties Correlating structure to melting point and boiling point Effect of impurities on mp and bp of compounds Density, vapor pressure, diffusion, osmosis Recognizing acids and bases Lewis and Bronsted-Lowry definitions Correlating pKa to acidity; pH, Conjugate acids and bases Identifying “acidic” and “basic” centers in a given molecule Correlating structure to acidity and basicity Chem I, II, III Chem II, III, IV? Chem I, IV? Chem I, II Chem I, II, IV Chem II, III Chem I, II, III, Adv.Org. Chem Recognizing polar and non-polar compounds Concept of dipole and dipole moment Understanding that polarity is a consequence of charges or net dipole present Evaluating the solubility of a compound in a particular solvent based on polarity Chem I, II Recognizing nucleophiles and electrophiles Definition of a nucleophile and electrophile Identifying “electrophilic” and “nucleophilic” centers Drawing correct electron shift arrows Nucleophilicity and basicity; the variation depending on the nature of the solvent used Chem II Recognizing structural properties Presence (if any) of isomerism, resonance, tautomerism, aromaticity, epimerisation and zwitterionic existence of a molecule Chem II, III, Adv. Org.Chem, Biochem Chem II, III, Adv. Org.Chem, Survey of Instr? Lab Methods? Recognizing spectroscopic properties 6 APPENDIX 2 VI. Assessing Knowledge of Solutions What is a solution and what does it look like? How is a solution different from a pure liquid? Solutions can be made in one or two ways: a) Diluting a more concentrated solution b) Dissolving a solute in a liquid In order how to figure out how to do (a), need to know what volume of the more concentrated solution is needed to make the dilute solution. In order to do (b), it is necessary to know the mass of the solute. Solutions are usually discussed in terms of concentration or the amount of solute. There are several ways to define this, including: a) molarity b) % c) (5x, 10x, 50x) d) normality What are the units for each of these types of solutions? Do all these units apply to solutions made from either dilution of stronger solutions or from the solid? Molarity and normality can be done for either type of solution, but % is for solutions prepared from solids only and 10x is for dilutions only How are these calculations done? Students should be able to solve either for mass or volume for any type of solution given its concentration and the volume desired What happens chemically when a solute is mixed with a solvent? Is there a chemical reaction, a dissociation, or no change in the solute? Why do different solutes do different things? What is the solvent? Most commonly it is water and what special properties does water have to make it such a common solvent? (This is especially true when discussing biological solutions) Can chemical reactions occur when solutions are mixed together? Does this ever occur or does it never occur and on what does it depend? 7 APPENDIX 2 VII. Assessing Understanding of How to Separate Compounds What is the difference between a mixture and a contaminant? A mixture means more than one molecule is present in significant amounts and a contaminant means one or more molecules are present in small amounts The purification scheme used will be different if it is a mixture or a contaminant (There is an excellent example of this in Chem II Lab) Why is this so? What does it mean to completely purify a compound? How is it possible to know if this has occurred? The answer varies depending on what the compound is: organic molecule, protein, DNA, etc. Do methods to remove contaminants take advantage of specific properties of contaminants or do they work in general? To separate a compound from a mixture, what methods can be used and what properties do they take advantage of in the molecule? This is the opportunity to discuss the various types of chromatography, how they work and what property is being exploited in the compound (size, charge, polarity, etc.) Since chromatography is essentially always a way of separating compounds, the various types should be discussed. In all of these separation methods, is the molecule being chemically altered? Are any chemical reactions occurring? Why is it necessary to frequently use more than one method to separate a mixture and what, if anything, determines the order of the methods? 8 APPENDIX 2 VIII. Assessing Understanding of Atomic, Molecular and Macromolecular Sizes 1. Understanding how protons, neutrons and electrons contribute to atomic size. 2. Understanding how the size of atoms changes with increasing atomic number. 3. Comparing the sizes of neutral atoms with their ion counterparts. Predicting the sizes of ions depending on their charge (+ or -). 4. Visualizing the three-dimensional structure of substances such as ionic compounds and molecules to scale. For example, lithium iodide, CH3OH and glucose compared to H2O. 5. Understanding the relationship between molecular size and MW (g/mol or Daltons) 6. Understanding that the size of a molecule depends on the number and size of the bonded atoms that make it up. 7. Understanding what Van der Waals radii represent in the space-filling models of molecules. 8. Understanding relative sizes in the structural hierarchy from the atomic to organism level (atoms → molecules → macromolecules → supramolecular assemblies → organelles → cells → tissues → organs → organism). Using powers of 10 to illustrate this hierarchy. 9. Understanding that macromolecules (DNA, protein, glycogen) are made up of smaller molecular building blocks (nucleotides, amino acids, glucose) 10. Knowledge of methods for separating molecules, macromolecules, supramolecular assemblies and organelles based on size. Chromatography, centrifugation, electrophoresis, dialysis. 9