What Do Incoming Freshmen Remember From High School Chemistry? Robert J. Niedzielskl and Frank Walmsley Department of Chemistry, The University of Toledo, Toledo, OH 43606 The Toledo Chemistry Placement Examination (TCPE), an American Chemical Society Cooperative Examination (11, was developed at The University of Toledo by Hovey and Krohn (2).I t has been used by many schools as an effective predictor of success in a typical General Chemistry course (3). The 1974 form of the examination, in current use, is of the multiple-choice single-response type. As noted in Table 1, it is comprised of six parts containing 67 questions, for a 100point total. At The University of Toledo, a state-supported urban university with an open admission policy, the General Chemistry sequence is required for all Science, Pharmacy, and Engineering majors. Of the last group, only potential Chemical Engineers complete the three-quarter sequence-all other Engineering majors require the first two quarters only. The sequence prerequisite is a score of at least 45 on the TCPE, or the successful completion of a deficiencies course, Chemistry 100, Elementary Chemistry(4). This preparatory course is thus populated by students who score helow 45 on the TCPE, as well as by students who have not had high school chemistry. The latter students are not required to take the
-.
TCPl? -
This paper examines the TCPE results for 3227 entering students a t The University of Toledo who took that examination during the period 1977-1980. I t is estimated that greater than 99% of the students in the sample had taken a t least one year of high school chemistry. Many of these students, however, have been away from high school chemistry for a t least a year. Thus, the TCPE should not be viewed as a final exam taken when the course is still fresh in the students' minds. Two aspects of the test results are emphasized in this report. The first of these is concerned with general trends developed during the 1977-1980 period. The second deals with specific concepts, both chemical and mathematical, and identifies some of the misconceptions which high school students bring to their college chemistry studies. General Trends As has been reported by a number of investigators (51,there has been a decline in the abilities of entering freshmen chemistry students over the past several years. Table 2 documents this decline as reflected on the TCPE. Both the average score and the percentage of students scoring 45 or better (passing) at The University of Toledo have declined steadily from 1977 through 1980. It is interesting to note that in 1967 the overall average score for 657 students was 58.9, while the percentage of students passing stood at 82.8. Admittedly, this was not the same TCPE version as the 1974 test, but the examination was of an equivalent nature ( 6 ) ,and the contrast with the current results is startling. Breakdown of the test results by sex of the examinee also provides interesting comparisons. The decline in percent passing is regular for male students, hut irregular for females over the period. At the same time, a much higher percentage of males pass the TCPE than do females. Males in both the passing and nonpassing groups have also done better than their female counterparts in a comparison of the year-by-year test scores. For the passing groups, average scores on the separate parts of the exam are closely comparable in each year,
Table 1. Toledo Chemistry Placement Examination Form 1974 Part
Subject
I 11 111 IV V VI
Arithmetic and Algebra General Chemical Knowledge Formulas and Nomenclature Chemical Equations Algebraic Formulation Chemical Problems
NO.of Questions
NO. of
15 25 10 6 6
15 25 10 12 18
5
20
Points
Table 2. Trends 1977-1980 Overall average score Percent of students passing Percent of males passing Percent of females passing Percent of students who
51.8 64.9 68.8 57.8 36.0
50.6
48.6
64.2 67.2
59.4 65.9 48.8 310
59.2 35.5
48.3 56.1 59.4 49.5 32.8
.re famale
except for Part VI, Chemical Problems, on which males regularly scored higher. Again, in the nonpassing groups, average scores for the separate examination parts compare closely each year except for Parts I and 11, Arithmetic and Algebra, and General Chemical Knowledge, respectively, agaid in favor of the males. One other observation bears mentioning. In light of the increasing numbers of females entering college nationally (7) and with more females choosing engineering curricula, it was surprising to find that the percentage of female examinees declined from 1977 to 1979. The increase noted in Table 2 for 1980 may signal a reversal of that pattern, however. In 1967, only 17.0% of the TCPE papers were written by females. Scores By TCPE Paris Before considering. suecific conceuts. i t is instructive to . diwuas rear r e d t s un thcstparare parts of the ~ s ; u n i n : ~ i ~ m ~ . Since ir ia diifirult to h i d e on a sveciric urrrmnnnre Iwel for all items, only relative comments are &I order. As an alternative, the reader may choosehis or her own interpretation. Thus, 100% of the students should be expected to answer correctly a simple question that asks for the sum of two plus three; the acceptable percentage level for another question that asks for the quotient of two decimal numbers, which can be argued to he equally simple, still remains. In this paper, the minimum passing score, 45%,has been taken as the value for comuarison.
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range of average percentages was 80 for Part I, Arithmetic and Algebra, to 56 for Part IV, Chemical Equations. On Part 111, Formulas and Nomenclature, the average score in each of the four years surveyed was approximately 45, while for Part VI, Chemlcal Prohlems, the score was consistently 42. Thus, ~t appears that students entering the General Chemistry sequence at The Umversity of Toledo are generally weak in Presented in pari at the 181st Natlonal Meeting of the Arner~can Chemical Soclety, April 3, 1981. Volume 59
Number 2
February 1982
149
writine formulas, namine com~ounds.and solving- chemical prohlems. The eronp of students that did not pass the TCPE scored hetter &an 45%only on Part I, with an average score of 51 over the period. The range of average percentage values for the other parts was 41 for Part V, Algebraic Formulation, to 16 for Part VI. If these students, who are directed to Chemistry 100, as mentioned earlier, bring with them any previous knowledge, it is in the area of elementary mathematics. Specific Concepts
Some of the soecific concepts that are tested bv the TCPE what can he considered to he the most important concepts tested. or to indicate simificant misconceutions or difficulties. The percentage correit listed for the three groups is taken ftom the 1980 test sample of 1043 students. Results from previous years are comparable. The sinele question on oxidation number simply asks for the oxidation number of one element in a given-cimpound formula. The percentage of students correctlv answering this question is quite low; even for the passing group. 1; the question which has been designated as a definition of oxidation, a chemical equation is given involving metal halides, with the correct answer identifying the element being oxidized. This time the results are considerably poorer. The more disturbing aspect of this question is the fact that over 50% of the examinees chose the response that said no oxidation was occurring because no oxygen was present in the reaction. Since the inception of CHEM Study, high school chemistry courses have tended to mimic the college courses of their time and thus have tended to place a great deal of emphasis on atomic structure and chemical bonding. The five questions nertinent to these areas cited in Tahle 3 are of a verv basic nature. Students do not have to concern themselves with orbitals, quantum numbers, hybridization, and the like, in order to answer the questions correctly. But, students are expected to recoanize that electrons are lost when a cation forms from an atom, to determine the number of neutrons and the number of valence electrons contained in a species, given its atomic and mass numbers, and to distinguish between an ionic and a covalent bond between two atoms, given their electronegativities. The results on questions of this sort again are poor, however, and suggest a great deal of confusion. Thus, only 40% of those students who passed the TCPE correctly determined the number of neutrons present in the nucleus, and 40% of the same group also suggested that FrF was covalent. Knowledge of metric-English conversions is fairly good. Even though only 66% of the group as a whole correctly identified the number of centimeters in an inch, 96% at least recognized that an inch is longer than a centimeter. One question asks for the designation of the most reactive nonmetal in agroup of elements which includes sodium as one of the choices. One-third of the students overall chose sodium in this case. They may have remembered a demonstration of the reactivity of sodium metal, or they may have misread the question, or they may not realize that nonmetals can he quite
Table 3.
Percent Correct on Soecitic Conceots Number of
Not
Concept
Questions
Passing
oxidation number definition of oxidation atomic structure
1 1
3
30.5 19.2 51.1 32.1 67.6 41.6 49.0 77.6 28.1 43.5 82.1 80.8 76.7 79.3
18.6 8.4 27.7 22.7 38.7 24.3 32.2 39.7 10.3 23.9 54.3 57.4 41.5 45.0
25.4 14.6 41.0 27.7 59.9 33.9 43.3 60.9 20.2 35.1 70.1 70.5 61.4 64.0
3
73.5
36.3
57.1
bonding
metric-English conversions metals, nonmetals, reactivity nomenclature and formulas balancing completed equations gas law calculations molarity simplest algebra numerical exponents algebraic manipulation from words word problems
3 2 2 1
8 2 2 1
6 2 2
Passing Everyone
Ph(CzH30z)z was lead carbon hydrate. Formula derivation from parent compounds also presented difficulty, as only 24% of the students overall responded correctly. I t is not easy to discern the reason for the incorrect choices in this case, unless it is simply confusion with the oxidation numhers of oxygen and hydrogen. The identification of completed halanced equations, with coefficients given, fared much better. The nonpassing group, however, responded only half as well as the passing group. The results for gas law calculations were the second worst of the categories which have been examined. The percentage of nauers which omitted these two auestions was also un . . S I I I I S I . ~ I Iand, ~ : ~ I111 I ~tht . C , I W cei the 1i.mp.1~s111~ g r w p , the wrr?;t reapmat ni~.t \ j l i t :ill\ i t i f i l t h plr1c 1.111t.r 111ei r i ~ ~ ~ r r ~ t t respon,t- :lnd i h < ww l i , ~~miittril111,. q11tstiun,, Tlit proI)l,mi. , I ~ I ~ I,I~C i : ~,,I m f h t C..nnbint.(l(:.IS i n I tr.~:it mure itreis should he pluccd (311 iunoan~entala.l%ltrt.k1,5I lras rmorted that the ~ ~ h ~ k . t ~ - h a sniuvcment ics" in the puhlic schools has not included the teaching of science. High school students need more practice in writing- formulas and in naming compounds. There needs to be more emphasis on basic atomic structure and more descriptive chemistry. For the college teacher, areas where more emphasis is needed or a more thorough review of fundamentals is required have been identified. These include topics just listed, plus chemical bonding and solving chemical problems 111s~rurt~rrs nwtl 13 plan their uwn stri~teyieswith thr rt:;ili~atimthat the diliicultie, are not wsy to wive. Even wht.11 an area is identii;ed for rorrwt1tm, the initial mtvh~>di uqed to arwmplish thr gual ma!. not he totally cfiet live. Attcmpth h i w heen made ;I! l h e i'nioeriit~~ d l d e tdo i~ k~e >tudvn~s to learn simple inorganic nomenc"lature (9).This effort began with including extensive drill-type questions on exams and with using names in questions when the formula was needed. This was not successful so sevarate examinations are now administered which the student must pass (13 of 15 perfect) in order to aualifvfor a vassine grade in the course. The results have been good, but st;dents y e still not as proficient as their countervarts of fifteen vears ago. I.a.,t, b111cerrai~~l!not k3.1, p~rllnpsthia rcpurt III;I!. iuster dialwlw hetween hirh i r l ~ w.md l n,lle:r rhen~iitryteachers. waggoner (10) has fbund a substantialdifference in the perceptions of high school and college General Chemistry teachers in Northwest Ohio with respect to 285 chemistry content items. A mini study, however, indicated that greater agreement existed when there was prior interaction of the two groups with each other. Literature Cited i l l Direct inouiries to: Examinations Committee-ACS. Universitv of South Florida, Tampa, FloRda 32620. Norms u e available upon requeat. (2) Hovey, N. W., and Krohn, A,, J. CHEM EDUC., 35,507 (1958). (3) H O V ~ N. ~ ,w . , ~ ~ K ~ ~ J. CmM. ~ ~ , EDUC., A . , 40,370 (1963). (4) Waimsley, F., J. CHEM.EDUC., 54,314 (1977). (61 N ~ n rF T V ~ ~~ ~~ ..IT~ .s. . ~ Y.. cro3hv. ~ ~ and s, h k . JI..P.. s v m a o s i u m o n ~ c a , ~ ~ G.A. 8 CHED 73178. 1'81st ACS ~atjonal~kt ing, Atlanta,
.. .
.
(6) Personal Commu'ieation, A. Krohn. (7) The Chronicle o/Hi#heiEduraBon. 21, (12). 4 (1980). (8) ~h~ c h i o n i c i e o i ~ ; g h ~ i ~ d u c a t i o n ,(7). 2 i ,4i1980). (9) Niedzielski. R. J., CHED paper 1s.178th ACS National Meeting, Washington, D.C., September 10, 1979. (10) Waggoner. C. A., Ed. D. Thesis, The University of Toledo (1979).
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Number 2
February 1982
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