PERCOMP.CAL a Supercalc(tm) template for chemical percent compositions by Stephen J. Cebula INTRODUCTION PERCOMP.CAL is a sample template for determining chemical percent compositions in Supercalc 2. It contains the worksheet for a sample molecule already, but you can fill in the data for the molecule you are looking for. All of the elements are not listed merely for convenience, because, a template of over 100 elements is a bit impractical to solve a percent composition problem for a molecule with only 3 or 4 elements. PERCOMP.CAL was created by Stephen Cebula as an exercise from his chemistry 101 class. It serves as a useful example of how the computer can be used by a student other than for word processing. FORMULAS When you insert new elements in this template, pay close attention to the formula used to determine the individual percent composition for an element. It is the net mass of that element in the molecule, divided by the total mass of the molecule, times 100 to get a percentage. A sample formula for column E which represents the individual percent composition would look like this for the element in row 20: D20/D25*100 where D25 represents the total molar mass of the molecule and D20 is the net mass of the element. Here, oxygen (O), has two atoms (from data in column C) and an atomic mass of 15.994 (for each oxygen atom). Therefore, the net mass equals 2 times 15.994 or B20*C20 in Supercalc notation. A little reminder, when you insert or delete atoms in this list, you should also make sure that the equations are in the same form as the original ones, Also, you must make sure that the cell representing the total molar mass (D25 in this case) is the sum of all net masses. It is SUM(D8:D23) in the original version. USAGE NOTICES This template is for the public domain only. It may not sold or published in any form without permission of the author, Stephen J. Cebula; if you have any ideas to improve this template or for other useful applications for students, please feel free to contact the author via mail or one of the following Pennsylvania bulletin boards: Allentown RCP/M 215-398-3937 CTS RCP/M 215-947-3615 System-2 TBBS 215-825-3205 or write: Stephen J. Cebula 2349 Packard Avenue Huntingdon Valley, PA 19006 OTHER VERSIONS Enjoy this Supercalc template. It serves as a example of how the computer can be of use to non-Computer Science majors in an educational setting other than just word processing. The same technique can be used with other spreadsheets to solve the percent composition problem. A version of this template exists for Multiplan(tm) in CP/M(tm) and Apple Macintosh(tm) form. If you are interested in such items, just contact me in one of the forementioned ways.