Spreadsheets in Chemical Calculations

In the first example, chosen to show that it is possible to solve a whole family of problems in little more time than it takes to do a single one when one doesn t use the spreadsheet, we will learn how to label columns needed in the exercise, dealing with expressions of concentrations of aqueous hydrochloric acid, enter data of interest, and use formulas so that the data can be transformed into the desired answers to the question(s) asked. We will also learn how to prepare a graph comparing the variation of molarity and molality as a function of %HC1. Also, by determining the percent difference between M and m at various concentrations, we will be able to judge when it is reasonable to substitute the more convenient M for the more rigorous m in equilibrium expressions. 

In earlier editions of the Handbook of Chemistry and Physics (CRC Press), percent composition and specific gravity data for solutions of many common reagent solutions are given. Let us take, for example, pairs of values for aqueous hydrochloric acid (%HC1, sp gr at 25°C) from the Handbook and copy the data into Quattro, and then calculate the molarity, molality and mole fraction of HCl for each of these solutions. 

At this point, although we have dealt with all of the necessary formulas and data, the spreadsheet seems almost empty. This can be readily corrected by means of the Copy function. The copy command is /EC /BC /C ). The prompt will ask for the source block of cells. Respond by typing B2..F2 (where you entered the formulas earlier), then Enter. You will now be asked for the destination. Enter the uppermost cell on the left (B2) and the lowermost right one (F15), thus B2..F15, then Enter. You will be rewarded by seeing the entire spreadsheet generated quickly (Table 1.2). 

It will be useful to have a graphical display of the way in which M, m, and their %dif. varies with concentration (expressed as wt% HCl). Review the /G pulldown menu and the section in the Manual. Use the command /GGX /GGX /GG to bring you to the graph menu and to select an XY type graph. Now select X, which allows you to specify the block of cells 

In this exercise, you will learn a spreadsheet technique which will permit a spreadsheet to serve as an on line resource that can provide a convenient 

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