Graphing using spreadsheets

You should see a peak in the absorbance at about 660 nm. Obtain the precise maximum absorbance at the peak for each solution, and prepare a bar graph (use spreadsheet software) of absorbance vs. solvent. 

The values for ionization energy in the periodic table in Appendix C are first ionization energies. Construct a bar graph to show the relative sizes of lEi values for the main group elements. If available, use spreadsheet software to plot and render your graph. 

If you plan to use spreadsheets in this course, you should know how to enter formulas in a spreadsheet and how to draw a graph of data in a spreadsheet. 

One of the most useful tools to spot and eliminate errors is a spreadsheet, such as Excel or QuattroPro. QSAR modelers very frequently use spreadsheets to organize data into columns and rows of standardized values of the independent and dependent parameters. Spreadsheets allow easy sorting and filtering — two important functions used to find problem data and duplicates and other errors. In addition, spreadsheets have search and replace routines, plotting, and correlation functions, which allow the data to be reviewed in various comprehensive ways. The data can also be exported to other file types, which allow analysis by other software for statistics and any types of quantitative and qualitative relationships that may exist. It cannot be emphasized enough that the typical spreadsheet functions (including graphing functions) are excellent tools to find and eliminate erroneous or questionable values, duplicates, and other problem entries. 

Go to Insert o Chart etc. to make an xy graph. Using the mouse and the vertical slide-bar on the right of the spreadsheet, move the cursor to the top of the sheet, and deposit the chart symbol in cell FI. Plot the (vertical) log c scale from -10 (at the bottom) toO (atthetop), the (horizontal) pH scale from Oto 14. Alternatively you can use the... 

Once it has been verified that the data can be properly fit to a one-compartment bolus IV model, a linear regression analysis is performed on the data, with time (t) entered as the independent (x) data, and In(Cp entered as the dependent (y) data. Linear regression analysis can be performed on calculators that handle two-variable statistics, or using spreadsheet, graphing, or statistical analysis software on a computer. The analysis should provide values for the intercept (b) and the slope (m) that provide the best possible fit to the measured data in the form y = b + mx, as illustrated in Figure 10.23. The linear regression analysis also often provides a value called the correlation coefficient (r). 

Excel can be used to produce graphs of various kinds (Excel refers to graphs as charts ). We present a procedure to constmct a two-dimensional graph using the Chart Wizard. The graph is constracted from values of an independent variable in one column values of a dependent variable in another column. These values must first be loaded into the columns. After the values have been loaded into the spreadsheet, you follow the procedure ... 

The mean demand is 85 units and the standard deviation is 4.43 units. The same data can be plotted as a histogram or as a line graph using a spreadsheet. 

The correlation function for a particular relaxation process can be well described by the Kohlrausch-Williams-Watts function C(x) = 6xp[—(t/tk) ] with tk = 20 ms and p = 0.32. Show by plotting suitable graphs, using a spreadsheet or otherwise, that, in the region X = 0.25 100 ms, the correlation function can be well simulated by the following sum of exponential functions ... 

When all of the cells F2..N2 are prepared, the copy command /EC /BC /C from F3..N16 will complete the spreadsheet. Construct the graph using pH for the X series and as the six Y series log[H2C03], log[HC03 ], log[C03 ], and the three pointers. (If QPRO is used, the annotate function will permit you to conveniently draw the two lines corresponding to log[H] and log[OH].) Figure 4.4 represents the graph just described. 

The property calculation experiment offers a list of 34 molecular properties, including thermodynamic, electrostatic, graph theory, geometric properties, and Lipinski properties. These properties are useful for traditional QSAR activity prediction. Some are computed with MOPAC others are displayed in the browser without units. A table of computed properties can be exported to a Microsoft Excel spreadsheet. 

STRATEGY We need to plot the natural logarithm of the reactant concentration as a function of t. If we get a straight line, the reaction is first order and the slope of the graph is —k. We could use a spreadsheet program or the Living Graph Determination of Rate Constant (first-order rate law) on the Weh site for this book to make the plot. 

The rate constant for the alkyl bromide reaction is equal to the slope of the line. The best way to determine a slope is by doing a linear curve fit using a spreadsheet or graphing calculator. Somewhat less accurately, any two points on the line determine the slope ... 

Use a spreadsheet such as EXCEL to obtain a graph of absorbance versus concentration for the following data. 

Six 25 ml volumetric flasks are filled with 10 ml of the analyte and then 1, 2, 3, 4, 5 and 6 ml of a standard solution containing 6.5 x 10 3 moll-1 of the same analyte. 5.00 ml of color-developing reagent is added to each flask and enough distilled water is added to bring each flask to exactly 25.0 ml. The absorbances of the five solutions were 0.236, 0.339, 0.425, 0.548, 0.630 and 0.745, respectively. Use a spreadsheet to obtain a graph of the data and extrapolate the data to obtain the information needed to determine the initial concentration of the analyte. From the data, estimate the uncertainty of the result. 

Test your IT skills. Try creating Excel spreadsheets based on the Michaelis-Menten equation (Equation 2.9) and its variants (Equations 2.10 and 2.11). Insert into your spreadsheets your own values for JCm, Vmax, [S], [I] and A) and use Excel to plot Michaelis-Menten, Lineweaver-Burke and Eadie-Hofstee graphs. 

Using graph paper or spreadsheet software, plot and label a graph that shows the rate of formation of oxygen gas. The concentration of O2 (in mol/L) is the dependent variable and time (in s) is the independent variable. 

Purpose of the spreadsheet (e.g., calculation of linear regression, including equation, graph, and formula used)... 

Bill Excel LINEST function. Enter the data from Problem 4-23 in a spreadsheet and use the LINEST function to find the slope and intercept and standard deviations. Use Excel to draw a graph of the data and add a TRENDLINE. 

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