IDENTIFYING STUDENTS MISCONCEPTIONS IN A-LEVEL ORGANIC CHEMISTRY

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1 IDENTIFYING STUDENTS MISCONCEPTIONS IN A-LEVEL ORGANIC CHEMISTRY Lim Choon Huat Bryan Innova Junior College Abstract In recent years, research in science education has been focused on identifying and addressing students misconceptions. This is an area of major concern as students learning can be seriously impeded if their misconceptions are not dealt with. Though many students view Organic Chemistry as a topic which relies heavily on memory and recall, there are actually a number of concepts which students are required to grasp in the A level curriculum. The purpose of this research is to identify and analyze junior college students misconceptions related to Organic Chemistry. A detailed study was conducted on 60 students from a junior college in Singapore, through the use of interviews, test scripts and an Organic Chemistry Diagnostic Instrument. Some of the misconceptions were due to misinterpretation of the content found in lecture notes by students, while others were actually perpetrated by teachers. Identification of these misconceptions allows teachers to clarify them with the students, as well as to reflect on their own teaching and pedagogy. Introduction One of the main barriers that students encounter as they seek to understand science is misconception. Teachers can be astonished to learn that despite their best efforts, students do not grasp fundamental ideas covered in class. Even when some of the best students give the right answers, they are often only using correctly memorized words. When probed further, these students reveal their failure to understand the underlying concepts fully. Students are often able to use algorithms to solve numerical problems without completely understanding the underlying scientific concept. According to Mazur 1,

2 students in his Physics class had memorized equations and problem-solving skills, but performed poorly on tests of conceptual understanding. Nakhleh 2 conducted studies on sixty students in an introductory course for chemistry majors. In an exam which paired an algorithmic problem with a conceptual question on the same topic, only 49% of those students classified as having high algorithmic ability were able to answer the parallel conceptual question. Thus, in our role as teachers, besides offering students information and helpful examples, we must also guide them on the reasoning processes that lead to algorithms and conceptual generalizations. In many cases students have developed an ability to provide correct solutions to exam problems and questions most of the time, not so much via correct reasoning and conceptual understanding, but rather because they have either come up with generalizations or are familiar with the often-featured questions. This can have huge implications when they move on to further learning, as the lack of an appropriate understanding of fundamental concepts from the beginning of their studies can interfere with subsequent learning. Students misconceptions and learning difficulties in science have been an active area of research for the past couple of decades. 3,4,5 Most of the work dealing with students misunderstandings, learning difficulties, and misconceptions in Chemistry has been focused on relatively classical examples, such as the mole concept 6,7, chemical bonding 8, entropy 9 and chemical equilibrium 10. In this paper, the misconceptions and learning difficulties that students have for A level Organic Chemistry are investigated and presented. Traditionally, organic chemistry has been thought of as too difficult for beginners, and interviews with students as they learn the topic seems to corroborate this idea. Due to the lack of curriculum time and the students lack of sufficient background in organic chemistry (from secondary school), teachers often resort to providing students with generalizations and solutions to problems with little elaboration. Methods 1) Surveys During the department s weekly professional sharing session, a group of Chemistry teachers gathered to discuss possible misconceptions that students may have in Organic

3 Chemistry. These misconceptions were gathered from interactions with students during tutorial lessons and consultation sessions, as well as from student responses in examinations and assessments. From the list of possible misconceptions, an Organic Chemistry Diagnostic Instrument was developed and administered to students. The responses of students were then gathered to identify the list of misconceptions that students have for A level Organic Chemistry. 2) Interviews Interviews were conducted with 30 Junior College Year 2 students to examine their perception and understanding of Organic Chemistry. Their responses to some questions in the Organic Chemistry Diagnostic Instrument were also clarified and analyzed to further validate our findings. At the same time, a number of learning difficulties (conceptual) that students experienced in Organic Chemistry are also identified. Results and Findings The list of misconceptions and learning difficulties that we have gleaned from the results of our diagnostic test and interviews with students are presented as below: Topic Introduction to Organic Chemistry Introduction to Organic Chemistry Introduction to Organic Chemistry Misconceptions/Learning difficulties In determining the presence of chiral carbon atoms, look for carbon atoms that are bonded to four different atoms. A molecule is considered to be optically active and capable of displaying optical isomerism if it contains at least one chiral carbon atom. As long as there is a C=C bond with two different groups on each side of the double bond, it can display cis-trans isomerism. Thus, 1- chloro-2-bromo-cyclohexene can also display cis-trans isomerism. Why are alkenes more reactive than alkanes, in spite of the fact that double bonds are stronger than single bonds?

4 Hydroxy compounds Hydroxy compounds Halogen Derivatives Halogen Derivatives Carboxylic acid derivatives Carboxylic acid derivatives Carboxylic acid derivatives Alkenes can only decolourise bromine in the absence of light. In the presence of light, alkenes do not decolourise bromine. How does the delocalization of π-electrons in the benzene ring make it more stable than expected? If the benzene ring is stable, why do arenes still undergo reactions such as halogenation and nitration? Why does OH activate, and Cl deactivate the aromatic ring towards electrophilic substitution? Aren t both groups highly electronegative and electron-withdrawing? When a 2,4-directing substituent and 3-directing substituent are both present in an arene and direct an incoming electrophile to different positions on the benzene ring, how do I know which position the incoming electrophile will be added to? Alcohols are alkaline due to the presence of the OH group. Phenols do not show any visible reaction with carboxylic acids because both are acids, and acids do not react with each other. In the addition of HX to an alkene, Markovnikov s Rule can always be used to predict the addition product. The reactivity of alkyl halides towards hydrolysis (reaction with NaOH) is in the order R-F > R-Cl > R-Br > R-I, as the more electronegative the halogen atom, the more reactive it is. Acid chlorides are more reactive than carboxylic acids towards esterification because it is more acidic. All molecules that contain the C=O group should undergo nucleophilic addition reactions, as it is unsaturated. Then why don t acid chlorides and carboxylic acid undergo nucleophilic addition reactions? During esterification, condensation occurs as water is produced. An OH group is lost from the alcohol, while H is lost from the carboxylic acid.

5 Nitrogen Compounds An aqueous solution of an amide will have a ph of more than 7 due to the presence of the NH 2 substituent. Amino acids have high melting point and boiling point as they possess strong intermolecular forces in the form of hydrogen bonds. Conclusion Studies conducted on Year 2 students from Innova Junior College revealed that they hold a number of misconceptions in Organic Chemistry. Some of these misconceptions are perpetrated by teachers, while some are conceived by students in the form of generalizations or incorrect ideas as they seek to ingest the huge amount of content. Teachers should try to include conceptual questions that assess students understanding of the underlying concepts in Organic Chemistry, rather than just set questions that only require mostly recall and rote learning. They would also do well to pay special attention to the misconceptions identified in this study, and address them in their teaching and interactions with students. Some learning difficulties experienced by the students in Organic Chemistry were also identified, unveiling the need to re-examine our teaching strategies so as to tackle these learning difficulties. References 1) Mazur, E. (1997). Peer Instruction: A Users Manual. Prentice-Hall: Upper Saddle River, NJ. 2) Nakhleh, M. B. (1992). Why some students don t learn chemistry. J. Chem. Educ. 69(3): ) Gallagher, J. J. (1987). A summary of research in science education Science Education, 71(3), ) Nusbaum, J. (1981). Towards the diagnosis by science teachers of pupils misconceptions: an exercise with student teachers. International Journal of Science Education, 3(2), ) Shymansky J. A. & Kyle, W. C., Jr. (1988). A summary of research in science education Science Education, 72(3),

6 6) Novik, A. & Mannis, J. (1976). A study of student perception of the mole concept. Journal of Chemical Education, 53(9), ) Duncan, I. M. & Johnstone, A. H. (1973). The mole concept. Education in Chemistry, 10, ) Peterson, R., Treagust, D. F. & Garnett, P. (1986). Identification of secondary students misconceptions of covalent bonding and structure concepts using a diagnostic instrument. Paper presented at the 17 th Annual Conference of the Australian Science Education Research Association, Adelaide, South Australia, Australia. 9) Frazer, M. J. (1980). Teaching the second law of thermodynamics. Report of a seminar held at the University of East Anglia, pp ) Gussarsky, E. & Gorodetsky, M. (1990). On the concept chemical equilibrium : the associative framework. Journal of Research in Science Teaching, 27(3),