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 100- point 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, Chem- istry 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 exami- nation 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 stu- dents, 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 stu- dents' 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 doc- uments this decline as reflected on the TCPE. Both the av- erage 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 ex- amination 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

NO. of NO. of Part Subject Questions Points

I Arithmetic and Algebra 15 15 11 General Chemical Knowledge 25 25 111 Formulas and Nomenclature 10 10 IV Chemical Equations 6 12 V Algebraic Formulation 6 18 VI Chemical Problems 5 20

Table 2. Trends 1977-1980

Overall average score 51.8 50.6 48.6 48.3 Percent of students passing 64.9 64.2 59.4 56.1 Percent of males passing 68.8 67.2 65.9 59.4 Percent of females passing 57.8 59.2 48.8 49.5 Percent of students who 36.0 35.5 310 32.8

.re famale

except for Part VI, Chemical Problems, on which males reg- ularly 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 i r ia diifirult to h i d e on a sveciric urrrmnnnre Iwel for all items, only relative comments are &I order. As an al- ternative, the reader may choose his 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.

- - 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 se- quence 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 Table 3. Percent Correct on Soecitic Conceots - 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 oxida- tion, 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 dis- turbing aspect of this question is the fact that over 50% of the examinees chose the response that said no oxidation was oc- curring 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 or- bitals, 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 num- ber 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 electronega- tivities. 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 wartive also ~ . . . . . . . - . - . .

, . I lir l:~r;e>t ~ i i~n i l~c r ,.ht.~i~istry t<.-i q w > t i < ~ ~ ~ s ,,II thr 'IX'PE 1111 1.1ded i n i l q ~ ~ . ~ r t i , u . t ~ r gr mp whi, 11 113' hv(.n ,11111-

I \ .~ed iall; i ~ i t , , I ht ~ ~ ~ , i i i ~ ~ i ~ I a t i ~ r c i9111l 1tmnu13 i I ~ ~ s ~ i i c ~ ~ i ~ ~ ~ i ~ . Not only are students asked to identify compound names, given formulas, and the reverse as well, but they are also re- quired to construct the formula of a compound from two other parent compounds; that is, given the formulas HA and Mz03, they had to arrive at the proper combination for M and A. Common errors in this group were of the expected type, such as confusine the -ous with the -ic acid, or ootassium and phosphor us^ and transposing the subscripts,but a distress- ingly large percentage of students suggested that HzOz rep- resented either hydrogen dioxide, or heavy water, and that

Number of Not Concept Questions Passing Passing Everyone

oxidation number 1 30.5 18.6 25.4 definition of oxidation 1 19.2 8.4 14.6 atomic structure 3 51.1 27.7 41.0 bonding 2 32.1 22.7 27.7 metric-English conversions 2 67.6 38.7 59.9 metals, nonmetals, reactivity 1 41.6 24.3 33.9 nomenclature and formulas 8 49.0 32.2 43.3 balancing completed equations 2 77.6 39.7 60.9 gas law calculations 2 28.1 10.3 20.2 molarity 1 43.5 23.9 35.1 simplest algebra 6 82.1 54.3 70.1 numerical 2 80.8 57.4 70.5 exponents 2 76.7 41.5 61.4 algebraic manipulation 3 79.3 45.0 64.0

from words word problems 3 73.5 36.3 57.1

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 I ~ : ~ I I ~ . and, 111 tht C,IW cei the 1i .mp.1~s111~ grwp, the wrr?;t reapmat ni~. t \ j l i t :ill\ i t i f i l t h plr1c 1.111t.r 111e i r i ~ ~ ~ r r ~ t t respon,t- :lnd i h < w w l i , ~ ~miittril 111,. q11t stiun,, Tlit proI)l,mi. i n I tr.~:<llttomvard , I ~ I ~ I I C , ~ i : ~ m ,,I f h t C..nnbint.(l (:.IS

i.:nv, ,ind d Ch.irItc3' I . ; I W . 3q~,ir :~tel , , Fur the ~1ru1~It.m .II-

wlvini tmlv the L4tit.r. .l <fi t l ie > I I I ~ I . I ~ I S U+II the C~el..iu3 ratherthanthe Kelvin temperature scale, an anticipated error,

of moles of solute A needed to prepare x liters of y molar so- lution was required, with x and y whole numhers. For the group as a whole, only 35% of the papers were correct, whde 45% gave one-half the correct value. For the nonpassing group, 24% were correct and 47% responded with one-half, while these two responses were even a t 44% for the passing group.

Throueb the vears. the sueeestion has heen made that the reason &dentshave difficuTiy in General Chemistry is that thev cannot handle the mathematics. As noted earlier in the disEussion of the scores on separate parts of the TCPE, this suooosition is not borne out in this studv. Tahle 3 indicates thisas well, although the differences hetieen the passing and the nonuassine rrouus are substantial. In the simplest aleehra - - . problem group, for example, the best percentage response for the passing students was 97, while the worst problem of the group had a 6590 correct response. These figures for the non- passing group were 80 and 33%, respectively. This pattern continued with the word problems. Thus, while 92% of the passing group could identify the algebraic expression for density from its written form, only 66% of the nonpassing students could do so. Seventy-four percent of the passing group could use the ideal gas law and the definition of n properly to solve for the molecular weight, compared to 26% of the nonpassing group. The nonpassing group thus appears to he reasonably competent in simple arithmetic, but con- siderably less so in algebraic manipulation. Essentially all of the omits for problems of this type also came from this group. One difficulty with algehraic manipulation that was apj,arent for the nonpassing group was the inability to deal with nega-

150 Journal of Chemical Education

tive quantities, both in addition and in multiplication. For the set of three "storv" or word problems, the results are similar to those for the simpler woid prohlems. In this case, a dis- turbine decline overall during the period 1977-1980 should be meitioned. For the three story problems, the percentages of correct responses overall were 88%, 62%, and 43% respec- tively in 1977; in 1980 those percentages had dropped to 83% 53%, and 35%, respectively.

Conclusions I t would he a simole matter to suggest that the findings -

reported in this study are not surprising and are merely in line with the national decline in SAT scores over the past manv years ,a). S m w hene1it.i ma!. result in,m this study. huwwvr. 'I'hc indiw~tion i w the high irhool teacher appears to In I h>it mure itreis should he pluccd (311 iunoan~entala. l%ltrt.k 1,5 I lras rmorted that the ~ ~ h ~ k . t ~ - h a s i c s " niuvcment 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~teyies with thr rt:- ; i l i~atim that 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 'nioerii t~ ~ d l d e d ~ ~ t o 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, b111 cerrai~~l! not k3.1, p~rllnps thia rcpurt III;I!. iuster dialwlw hetween hirh i r l ~ w l .md n,lle:r rhen~iitry teachers. waggoner (10) has fbund a substantialdifference in the per- ceptions 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 ~ ~ ~ ~ , A . , J. CmM. EDUC., 40,370 (1963). (4) Waimsley, F., J. CHEM. EDUC., 54,314 (1977). (61 N ~ F ~ ~ ~ ~ n r T V ~ ~ ~ . . I T . . s. Y.. cro3hv. G.A. and s h k . JI..P.. svmaos iumon~ca- ~ ~ , ~ ~ ,

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~ chionic ieo i~;gh~i~ducat ion ,2 i , (7). 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).

Volume 59 Number 2 February 1982 151