computer series, 140 First-Year Chemistry Laboratory Calculations on a Spreadsheet Paul A. ~dwards,' J. Brian McKay and Charles W. Sink Edinboro University of Pennsylvania Edinbom. PA 16444 The increased use of computers, particularly electronic spreadsheets, in chemistm wurses has been the subject of several articles in this ~ o ~ r n aMullin l. and Eierman 11)recently reported on the use of spreadsheets by students in rpaititative analysis. Levkovi2) and Van Houten (3, 4 ) have reported on the use of prepared templates by physical chemistrv students. and Whisnant (5) has ~rovided numerical and simulation templates for physical chemistrv. 'Ityo books (6. . , 7) . also have been ~ublished~rovidine simulation templates for use hy first-year chemistry students. Recently, we introduced the use of spreadsheets as a required wmponent of report writing in the laboratory of our firsbyear wurses for science majors (Principles of Chemistry I and 11). Our primary goals for introducing spreadsheets into the course were to provide students with the ability to: (a),do calculationsin a rapid, reliable, and easily corrected fashion; and 031, generate graphs that accurately reflect data and wmputational results. We also did not wish to remove the responsibility of doing the calculations from the students bv eivine them DreDared tem~latesas was done in most if ;he ikplem&titions listLd above. Rather. we elected to Drovide students with an introduction t i the use of sp;eadsheets first. Then we required them to generate their own templates to complete laboratory calculations.
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Software and Hardware Primarily, we use the spreadsheet program 20D0 (8)on the university's Digital VAX model 11-785 superminiwmputer operating under the VAXNMS operating system. We have also used MacIntosh versions of Micmsoft Works (9)and Excel (10).All output, including graphs, is printed on a laser printer. Students are not required to purchase anythingextra such as software or disks. One reason for our use of the superminicomputer over microcom~utersystems was better access for the students. More than 40 terkinals to theVAXand 15 MacIntosh computers are available to students in the Computer Center that is open day, evening, and weekend hours. This has been sufficient to meet the needs of up to 144 chemistry students along with students from other courses that require use of the VAX. Each semester there are three lecture sections of UD to 48 students each of Princi~lesof Chemistry Two s&tions of Principles of Chemistry iand I1 are offered each fall and s ~ r i n semester. e res~ectivelv.One section of Principles of ~LemTstry11 and I is also dffered each fall and spring semester, respectively. Each lecture section is divided into two laboratory sections of 24 students each. ~
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'Author to whom correspondence should be addressed 648
Journal of Chemical Education
JAMES P. BIRK Arizona State Universily
Tempe, AZ 85281
Students access 20120 through a local menu system called ASSIST. With ASSIST, students can accomplish all of their assigned tasks without havine to learn the VAXNMS operating system. One reason forusing 20120 on the VAX, rather than a PC or MacIntosh spreadsheet such as works, Excel, or Lotus 1-2-3(ll),is that it tends to minimize the sharing of templates among students. It is harder for most students to share files on the VAX, than those on microwmputer disks. Use of the VAX also eliminates the need to handle disks. Students must store wpies of their templates to their own data area. Faculty can then access the templates, either to provide help or for grading. Using the VAX has had unexpected benefits. Students can access the available electronic mail and VAX phone systems to get help. The VAX phone utility can be particularly effective.If faculty are logged in and accepting calls, students can get essentially immediate help with only a minimum of inconvenience to themselves or the faculty. Faculty have even used the phone utility to hold pseudo office hours on evenings and weekends by remotely accessing the VAX. Applications
We have written a laborator$ exercise to introduce students to the use of the VAX computer in general, with particular emphasis on 20120. This exercise has been used as the first eipcrirncnt in Principles of Chemistry I1 for three semesters and toward the end of Principles of Chemistw I for one semester. It is assumed that the student has little or no prior experience with computers, so the exercise begins with the most basic instructions includinghow to turn on the terminal and log into the system. As part of the exercise, students are encouraged to explore via the ASSIST menu the entire system including the local bulletin board, electronic mail. and the VAX ohone utilitv. Most of the exercise involves a simple calculation, converting 11 Celsius tem~eraturesto their Fahrenheit eouivalents. In the ~ r o ces; the students are introduced to:' entering data into the spreadsheet using the copy command storing and retrieving a template using the range command to control the number of significant figures displayed graphing
The Fahrenheit temperatures are plotted on the x-axis against the Celsius temperatures on the y-axis. The students are instructed to do a linear regression of the x against they values and compare the calculated equation to that used to make the initial wnversion. Originally, the linear regression was done using Minitab (12) that is also available via the ASSIST menu. This section has been modified because the latest version of 20120 includes linear regression as an available function. As a part of the familiarization exercise, the students also work with a template provided for the calculations associated with the estimation of Avogadro's number (an experiment wmpleted in Principles of Chemistry I). One reason for this, beyond providing practice in retrieving, entering data into and storing a template, is to give students a sample template for future reference. This is the
First -Year Chemistry Experimentsand Special Spreadsheet Requirements
Experiment
Special Spreadsheet Requirements
Solid State - Interionic Distances Acid-Base Titrations Colligative Propetties
Graphing - cooling curves
Red-Ox Titration Graphing Linear regression Equilibrium - Spectrophotometry Graphing Linear Regression Kinetics
Titration Curves Acid-Base Identification
Graphing -including derivatives Graphing - including derivatives
only time a template is provided. Students in Principles of Chemistry I1 must complete all their laboratory calculations using templates they develop. All laboratory exercises done in the Principles of Chemistry sequence are locally prepared versions of fairly traditional experiments. The instructions have only been changed for spreadsheeting purposes to include the name under which the tem~lateis to be stored and anv s~ecial requirements such aLgraphing and linear regre&ioi. Students are encouraged to use the traditional data tables and calculation instru&ions provided with the experimental procedures as guides for setting up their templates. A list of the experiments in Principles of Chemistry I and I1 for which calculations must be done on a spreadsheet is presented in the table. Any special spreadsheet requirements are also listed for each experiment. One advantage of this approach is that few changes are reauired in the laboratorv themselves. The . experiments . us6 of the spreadsheet program should be introduced in a separate exercise. After that. students could be reauired to a template for ess&tially any first-yea
