Research Questions :

1. Exploring students’ understanding of intermolecular forces Leah M. Corley, Melanie M. Cooper, Sonia M. Underwood Department of Chemistry, Michigan State University, East Lansing, MI, 48824 .. .. .. .. Intermolecular Forces (IMF) Assessment and Findings Background Information C2H6O Asked students to define their current understanding of the term “intermolecular forces” as well as the terms “hydrogen bonding”, “dipole-dipole”, and “London dispersion forces” Asked students to draw and label a representation that clearly indicates where the hydrogen bonding, dipole-dipole, or London dispersion forces (LDFs) are present for three molecules of CH3CH2OH. If the students believed the interaction was not present, they were asked to write “not present”. Structure-Property relationship Comparing where CLUE and Traditional students draw the location of hydrogen bonding using molecules of ethanol: Code Categories for Text: Code Categories for Drawings: Between Ambiguous Within Ambiguous Between Not present Ethanol liquid at room temperature Bp 78 °C Dimethyl ether gas at room temperature Bp –23 °C Between Drawing and Between Text E.S. = 0.65 Lindsay (CLUE): “When an electronegative atom within a molecule interacts with a hydrogen atom from another molecule. This is the stronges[t] type of intermolecular forces.” E.S. = 0.66 The process for connecting structure and properties1 Between Drawing and Ambiguous Text Ann (CLUE): “hydrogen bonded to an O N or F. strong” E.S. = Effect size *** = p-value < .001 *** *** Tobias (Traditional): “An intermolecular force between hydrogen and N O F. It is the strongest intermolecular force. ” Comparing the ways in which CLUE and Traditional students draw and describe the location of hydrogen bonding: Within Drawing and Ambiguous Text Steve (CLUE): “A bond where Hydrogen is bonded to a oxygen, nitrogen atom.” Previous Research E.S. = 0.67 Students have difficulty connecting a structure with the compound’s properties. Students were asked: “What information could be obtained from a Lewis structure?” Tracey (Traditional):“between a hydrogen and an electronegative atom such as, oxygen, nitrogen, or flourine [sic]. It is the strongest intermolecular force.” E.S. = 0.28 E.S. = 0.46 Percentage of students who stated each type of information2: Sally (Traditional): “it is an intermolecular force of attraction between a hydrogen atom and either a N, O, or F atoms.” Maeby (Traditional): “Hydrogen bonding is the stro[n]gest force; it is bettwen [sic] Oxygen or nitrogren [sic] or fluorine, and Hydrogen” E.S. = Effect size *** = p-value < .001 Acknowledgements Methodology Conclusions • Research Questions: • In what ways do students explain and depict intermolecular forces, specifically hydrogen bonding? • How do their explanations and depictions compare? Students enrolled in the CLUE curriculum depicted hydrogen bonding as occurring between molecules more often than traditional students. For both CLUE and traditional students, however, text responses were often not explicit in regards to whether hydrogen bonding occurs between molecules or within a molecule. A large number of traditional students provided ambiguous responses that, without viewing their drawings, sounded reasonable and could be interpreted as a correct definition of hydrogen bonding. We would argue that responses to open-ended assessment questions on IMFs may not accurately reflect students’ understanding of IMFs. Drawing representations requires students to construct their knowledge and provides a clearer picture of how they view IMFs. Setting: Conducted at a public southeastern university Participants: Collected from two equivalent groups of students (Traditional Group [N=94] and CLUE Group [N=87]) at the end of the second semester of general chemistry. References 1 Cooper, M. M.; Underwood, S. M.; Hilley, C. Z. Chem. Educ. Res. Pract.,2012, 13, 195-200. 2Cooper, M. M.; Grove, N. P.; Underwood, S. M.; Klymkowsky, M. W. J. Chem. Educ., 2010, 87, 869-874.