Alan Sherman Sharon J. Sherman
Middlesex County College Edison, NJ 08817
CHEM-DECK How to learn to write the formulas of chemical compounds (or lose your shirt)
One of the most difficult tasks in teaching preparatory chemistry is motivating students to learn. This becomes a very serious problem when the topic of chemical nomenclature is covered. In order for students to master this topic i t is important for them t o practice writing and naming chemical compounds, as well as to familiarize themselves with the common ions and their charges. Plagued by this problem year-after-year, we invented a card game that we hoped students would enjoy playing, and in doing so they would learn how to write the proper formulas of chemical compounds. We call this game CHEM-DECK and here's how it works. The objective of the game is to give students practice in forming chemical compounds. This is done by combining cation (positive ion) cards with anion (negative ion) cards and the proper number (subscript) cards to insure electroneutrality of the compounds. By playing the various card games with CHEM-DECK students will learn the charges of the various ions which will help them learn t o write the chemical formulas of many compounds. Of course, there exists the element of chance in this game; a person needs t o ohtain the proper cards to make compounds. However, by using their chemical knowledge, students should be able to manipulate the cards to form the best chemical compounds. (Best in this game means the compounds worth the most points-those with high molecular masses.) Before we discuss the rules for the various games, let us review some information about the CHEM-DECK. The deck consists of 88 cards. There are 18 cation cards, 25 anion cards, and 45 subscript cards. You can make your own deck by using heavy cardboard to cut out 88 cards of playing card size. Or you can simply take 88 cards from two decks of standard playing cards and paste the chemical symbols on them. The breakdown of the deck is as follows; one of each of the following cards, unless otherwise indicated. Nalf, NH41+,Agl+, K1+, LPC,Cu", Sn2+,CaZ+,Zn2+,CuZf,Mg2+, HgZ+,BaTf, Fe2+,Pb2+,AP+, Fez+ (two of these), Hl-, OH1-, C P , CZH30&, HCOQI-,C103'-, H804'-, NOpl-, 11-, B+, Hs041-, NO3'-, F1-, SO& COs2-, 02-, S2-, S O F , HP04=-, CrO42-, As043-, P043-, Pa-, N3- (two of these) 1(14 of these) 2 (15 of these) 3 (15of these) We chose ions that are frequently used in introductory chemistry courses. You can, of course, add more ions of your own. However, if you increase the ions in the deck, you should also increase the number of subscript cards in the deck by an equal amount. There are three basic card games students can play with CHEM-DECK: rummy, five-card draw poker, and seven-card stud poker. The rules are slightly different from those of Hoyle and will he explained below. Also, a tableof atomicmasses is necessary for scoring. CHEM-DECK Rummy
The object of the game is to obtain three compounds. I t takes four cards to make a compound (anion card, cation card and two subscript cards). Each player is dealt 12 cards. The regular rules of rummy are now followed as each player tries , to obtain three neutral compounds.
Scoring in the game is very important and adds to th' strategy of the players. The first player who obtains thre comnounds wins the hand and receives 50 points. This persoi lays;,ut his or her hand, as in regular rummy and addsup th molecular m s s ,,ieach rmnpound The sum of the molecula masses is then added tothat nlawr'sscure. Theother nlavcr add up the molecular masses bf their compounds (if they &v any) and add that to their score. The player who obtains 1,CO points wins the game. CHEM-DECK Five-Card Draw Poker
The object of this game is to obtain one compound, pret erably of high molecular mass. Each player receives five card! Players may then exchange up to four cards if they wish. T h player with the highest molecular mass compound wins t h hand. If no player has a compound, the player having t h heaviest ion wins the hand. CHEM-DECK Seven-Card Stud Poker
The object of this game is to obtain one compound. Th game is played exactly like ordinary seven-card stud. Scorin is the same as in five-card draw. Examples and Rules for Forming Compounds
A chemical compound is formed from a positively charge species (cation) and a negatively charged species (anion These species must be balanced to form an electrically neutri compound. The charges are balanced using subscripts. Example 1. Formation of sodium carbonate Na'+ cation, C0a2- anion forms Na2+ (C0d12- or usin CHEM-DECK
Example 2. Formation of potassium chloride K'+ cation. C1'- anion forms Kl1+C11'- or using CHEM
nL potassium
subscript
Evaluation of the Game
Cl1-
chloride ion
r subscript
Our students found the game fun to play, but did it he1 then1 learn 11, write the fi~rmulasotrhemicalcomnounds'? W ran an experiment to find out. Eight sections of basic chemistry were involved. Four se( tions were designated as the control group and four section as the test group. One hundred students were selected fro1 the control group and 100 students were selected from the ter Volume 57, Number 7, July 1980 1 50
g r o w to take the ore- and oosttests. These selections were made randomly. he same;nstructor (who was not the investigator) taught all eight sections.' The topic of chemical nomenclature was taught in the usual manner to all eight sections using lectures and the chaijter assigned from Basic Concepts of Chemistry.' A test, dksknated afithe pretest, waB given to both the control group and the test group. Following this test the topic was reviewed again. However, the review was run differently for each group. The review for the control eroun consisted of additional lectures and homework assignke&, which were then god6 over in class. The renew for the test group consisted of playing cards with the CHEM-DECK for each lecture session and one three-hour lahotatorv session. These review (or intervention) sessions lasted one week. In other words, prior to the posttest each . rroup - (test and control) had one additional week of review: a traditional review for the control group, and the CHEM-DECK review for the test group. The posttests were administered one week after the end of the review sessions. The results of the experiment are given below. Results
The results of the testing can be seen in the table. Analysis of the data shows that both group - scored similarly on the pretests. In other words, there was no statistically significant difference between the control and test groups (t = 0.61). Analvsis of the data also shows that the erouns did differ signit'icktly on the posttesta ( t = 6.08, the ;esuiu aresignificant at hetter than the 0.005 aluhn level and show that the test group did much better than the control group). An eyeball examination of the data shows the same thing.
504 1 Journal of Chemical Education
Retest
Posttest
-X = 67
-Y = 68
s_,= 11 X = 70 6, = 10
4. = 12 Y = 79 s,=11
Further analvsis shows that althoheh there was some statistically signikcant gain in the contGl group (t = 2.01, significant at the aloha eauals 0.05 level). . . there was a much more significant gain in the test group (t = 6.75, significant at better than the aloha eauals 0.005 levelL3 There sekms td he little doubt that for this populatibn the CHEM-DECK mouu showed imorovement in learning to write and name chemical compou~dn.One of the reanonsfor this was prohably that the student8 enjoyed learning the topic of nomenclature by playing a game. In~otherwords, there is not only a cognitive component to learninri hut also an affective one as w& students were interested in learning the topic so that they could play the game moreeffectivelv to win. We believe that this &me is & excellent tool for &aching this topic in basic chemistry.
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'The eight sections uf this cuurie ran over a two-year p e r i d . 'Sherman, A.. Sherman,S.,and Hurdkuff, I.., "Rauic Concepts of Chemistrv." Houehton Mittlin. Hoston. 1976. 1980. ~tstis&s were also run drith the' chi-square test using the McNemar test. The results were the same.
