dent is confidentof hisendpoint value, he can then calculate the pK. of the weak acid at several points along the titration curve. Program ACIDRASE-North Star Version 3 BASIC, 100 statements, no comments. Students run ACIDRASE via Hazeltine 1500 CRT. Execution requires 32K of &hit words on a North Star Horizon. Documentation includes listing, flowchart, comments, and several sample executions. Students are given instructions prior to execution time via written handouts, and a t execution time via the terminal. Copies of the listine and documentation are available a t a cost of $1 to cover postage and handling. Check or money order should be made out to the Universitv of Nebraska and mailed in care of James D. Cam, ~ e ~ a r t m eofn Chemistry, t at the address given above.
A Versatile Program for Drill in Inorganic Nomenclature and Formula Writing Cassen University of North Carolina at Charlotte
T.
oxidation slate specified unnecessarily incorrect oxidation state ( 6 ) failure to enclose a specified oxidation state in parentheses ( 7 ) use o l a n unnecessary subscript un the cation (8) incorrect symbol for the cation (9) incorrect symbol for the anion (4)
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When an error message is generated the user is given the option to try again, or to request that the correct answer he displayed. There is no limit placed on the number of attempts that the user may make to provide the correct response. However, if the user requests the correct answer, the options that are provided after a correct response will also be presented. The names and formulas of the compounds used in NOMEC are " eenerated from two data files: CATDAF, which contains the symbols, oxidation states and names of cations and 0x0-acids, and ANDAF, which contains similar information for anions. These files, which are established by the instructor with a program called LDAFIL, may be readily modified with a program called UPDATF. CATDAF accepts 29 cations and 18 0x0-acids. ANDAF accepts 21 0x0-anions and 8 anions of binary salts. NOMEC may be run via TTY, Tektronix 4010 graphics terminal, or DEC Dec-writer. The program contains 481 executahle statements plus 204 comments and requires 8 K 12lbit words for execution. Since these reauirements exceed the memory capacity of the DEC P D P 8/e'Edusystem 50 for which NOMEC is written. the Dronram is executed in five o M be E modified c "chained" segments. H ~ ~ ~ ~ ~ , ' N may
Gaining proficiency in naming and writing formulas for the inorganic compounds that are usually encountered in freshman chemistry is largely a matter of practice, once one is familiar with the rules. For the Dast two years we have been using an interactive, timeshaling BASIC program called NOMEC to orovide our -reneral chemistry students with the opportunity to practice naming inorganic compounds, and to practice writing formulas for inorganic compounds. The program, which is based on the IUPAC system of nomenclahandout, all of which are available from the author for $1,to ture, is currently capable of generating the names and correcover mailing costs (make check payable to: Chemistry Desponding formulas for over 800 different inorganic compartment, University of North Carolina a t Charlotte). pounds. Typically, students are provided with a handout in which the rules of nomenclature, and instructions for the use of our computer terminals are set forth. Other than a brief discussion of the handout, no lecture time is spent on noCalculators and Standard Deviation menclature. Our experience indicates that our students can learn inorganic nomenclature using NOMEC as well, or better, than they can through formal classroom discussion, and with Randolph Bruce Huff and Kenneth Nolon Carter a substantial saving of lecture time. Presbyterian College Access to the program is gained upon input of some kind Clinton. SC 29325 of user identification (which may he retrieved by the ins r r u ( t ~ rThe ~ . user i? tirst rlvtn rhe option of eirhrr nu~~~it~g One must exercise care when using the standard deviation function of an electronic calculator to make sure that the cacumr)uund; a how immula-. ;lrv zenerated by the wmput(.r, pacity of the calculator is not exceeded. This would not seem or o i writing formulas for computer-generated names. Upon a problem with a student using ten-digit calculator to solve specifying a choice for this option, the user is presented with formula (I), usually given in chemistry texts. However, stua second option: The choice of practicing on one of three dents using calculators to solve formula (2) or formula (3) may available classes of compounds or to practice on a random produce erroneous results since squaring the numbers first selection of compounds drawn from among the three classes. can easily result in the inability of the calculator to correctly The selection made for this option can he changed only by solve the problem. terminating the program and restarting it. The three classes ~ LN, -( 1X- ?I2 , of compounds are (1) 0x0-acids, (2) binary salts, and (3) salts .T = (11 of 0x0-acids. If the user chooses to name compounds, the computer will generate the formula for a compound in acx E , z i Z- ( ~ ~ , Z , ) ~ I N cordance with the choice that was made regarding the second (2) s= N- 1 option. If the user chooses to practice writing f&mulas, the name of a compound will he generated in accordance with the = (3) second option. In either case, the user's response is analyzed N-1 and acknowledged to he correct if it is so. After each correct Table 1gives a summary of results obtained from the following response the user is given the option to write formulas, name series of five weighings on an analytical balance: 6.1153, compounds, or terminate the program. 6.1159,6.1160,6.1161,6.1158.The results are given to the full On the other hand, aspecific error message will he generated extent displayed by the calculator to help give additional infor each of the following kinds of errors: sight. An answer of zero would obviously alert the operator to the (1) misspelled, or incorrect cation name problem, hut when the calculator is operating in the neigh( 2 ) misspelled, or incorrect anion name borhood of its capacity, it may give an erroneous result not a t (3) failure to specify the oxidation state of the cation when one once apparent, as demonstrated by the HP-45 result when the should be specified ~
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Volume 58, Number
1. January 1981 / 49
