Chemistry 1A Graphing Tutorial CSUS Department of Chemistry

Transcription

1 Chemistry 1A Graphing Tutorial CSUS Department of Chemistry Please go to the Lab webpage to download your own copy for reference. 1 When you open Microsoft Excel 2003, you will see a blank worksheet: Enter your data in the columns (A, B, C ) Such that your x axis data is in the left most column and the y axis data is to the right. 2 1

2 When you open Microsoft Excel, you will see a blank worksheet: Office 2007 looks like this: Enter your data in the columns (A, B, C ) Such that your x axis data is in the left most column and the y axis data is to the right. 3 Generating a plot: a. Select the entire set of data using your mouse. Then click on the Chart Wizard 4 2

3 b. Chart Wizard Step 1: Choose XY (Scatter) and the no line chart sub type, then press [Next]. c. Chart Wizard Step 2: Press [Next] and [Next] again. (assuming that you have correctly selected the data in step (a). 5 d. Chart Wizard Step 3: i) Select the titles tab, and enter a title that describe the data plotted. Your title should reflect the data plotted as well as the purpose of the graph. Example: "Experiment 6:Heat of Solution of Potassium Nitrate" Each axis should be labeled with the corresponding value and units. Example: Temperature (degrees C), Time (min) 6 3

4 ii) Click the gridlines tab, and turn on major and minor gridlines on both the x and y axis. iii) Click the legend tab, and turn off the legend (there will only be one set of data on the graph. 7 e. Chart Wizard Step 4: Select as new sheet Chart1, (rename your graph so that it has a unique identity) and press [Finish] f. Right mouse click on the center of the graph, select format plot area in the pop up menu, then click [none] in the left part of the window. This will remove the gray from your plot. 8 4

5 g. Rescale each axis to best fit the data by double clicking on an axis: h. Make sure that you have data points that are easy to see. Double click on a point to open the window to the left. Increase the size to 12 point font. 9 i. To print your graph, first go to the file menu and select Page Format, and select landscape. Go to the chart tab and select the print full page and print black & white buttons. Then hit print. 10 5

6 Generating a plot in Office 2007: a. Select the entire set of data using your mouse. In Excel 2007, go to Insert, Scatter, scatter with only markers. 11 In Excel 2007, you will get a chart within your spreadsheed. Right mouse the chart to get the option move chart in the pop up pull down menu. 12 6

7 Save your data plot as a new sheet, give it a name associated with the data. 13 Add the chart title and axis names by clicking the Design tab then Chart Layouts. You can edit the titles and font sizes on the chart by clicking on them or by going to Layout. Choose the chart layout that gives the most gridlines for both the x and y axis. 14 7

8 Add the chart title and axis names by clicking the Design tab then Chart Layouts. You can edit the chart lines and background by rightclicking on the chart and selecting format plot area 15 Rescale each axis by right mouse clicking on the axis: Choose Format Axis. Adjust the axis values to spread out your data on the plot. 16 8

9 Adjust the axis major and minor tick marks here. 17 Once you are finished your plot should look like this: 18 9

10 Each plot you make must have the following or points will be deducted: 1. A title that aptly describes the experiment run and the data plotted. 2. Each axis correctly labeled with units in parenthesis. 3. Major and minor gridlines with the major units labeled with values. 4. Clearly visible data points, not connected by lines. 5. The plot should be sized to fit most of the paper. You don t need fancy colors or jazzy fonts. Make sure your plot can be easily understood by somebody else. 19 Part 2: Data Analysis using the Excel Trend line function. For experiment 7 and subsequent experiments, you will need to find a y = mx + b formula for a line that best fits your experimental data. Recall that for linear x vs. y data, m represents the the slope of the line and b represents the y intercept. Once you have generated a scatter plot in Excel, it is easy to determine the values of the slope and y intercept linear regression "trend line" to the data. DO NOT ADD A TREND LINE TO YOUR EXPERIMENT 6 DATA! 20 10

11 Below is an example plot of linear X vs. Y data: Excel 2003 Place the mouse over one of the data points and click with the right mouse button. You can add a regression line to the chart by choosing Chart > Add trendline... A dialogue box appears. 21 Select the Linear Trend/Regression type. Choose the Options tab and select Display equation on chart Click on the Display R squared value on chart. The R squared values represent the straightness of the line. R 2 can have values of 0 to A value of R 2 = indicates that the line is perfectly straight

12 When you click OK, the line and formula of the line will appear on your plot. The y = mx + b line formula will have no units listed; you must interpret them from your data. Please see each experiments for the particular requirements for each graph. 23 On the Layout tab click Trendline then choose Linear Trendline. Right mouse on the line and click Format Trendline For Excel 2007: 24 12

13 At the bottom of the pop up menu, click on the Display Equation and Display R squared Value on chart. The equation and R squared value appear on the plot. Do not click on the Set intercept = 0 box. 25 You will need to adjust the font size and background on the line to make it legible

14 DO NOT ADD A TRENDLINE TO YOUR EXPERIMENT 6 DATA! 27 14