CHEM 1211& 1212 Lab
GPC - Dunwoody
Scientific Use of EXCEL
Part I. Graphing with Excel
Exercise 1. Density of Water
Given the data (i.e., density as a function of temperature) in the spreadsheet,
(1) Click on Insert from the main menu; Select Chart.
(2) Select XY(Scatter) under the Standard Type; Do not select the Line Type.
Then select the default or any of the five graph styles depending on the need.
Click on Next.
(3) Graph will appear with a default Data Range if the data are already selected.
If not, write in a data range: b10:c50 for example.
Or you may click on the red arrow icon in order to specify the range with a mouse
click/drag. Select Series in Column.
OR, you may do it in the Series as well: this is a longer method.
Select Series, then click on add.
Name:
Density of Water
X-Value:
=’pagename’!b10:b30
X-Value:
=’pagename’!c10:c30
Select Series in Column.
(4) Click on Next, then type the following in the appropriate fields:
Title:
Density of Water
X-Axis: Temperature (degree Celsius)
Y-Axis: Density (g/mL)
Click OK. Then mark As Object in (page name), and Finish.
(5) Chart will appear. It may need some minor cosmetic modifications.
Right click on X-axis, then select Format X-axis to make changes.
Right click on Y-axis, then select Format Y- axis to make changes.
(6) Right click on Plot Area, then select Format Plot Area to make changes.
(7) Right click on Chart Area, then select Format Chart Area to make changes.
You may change the color.
(8) Right click on one of the points of the series in the chart.
Click on Format Data Series Marker; you may change the point size or the color.
Exercise 2.
Kinetics of Decomposition of Dinitrogen Pentoxide.
Decomposition of dinitrogen pentoxide is first order with a rate constant of
k=0.00048 s-1. The initial concentration of N2O5 is 0.0165 M. Graph a time course for the
growth of the products and decay of the reactant:
N2O5  4 NO2 + O2
Copy the four columns for time and concentration data in the next sheet, then try to
reproduce the graph with three series curves.
Part II. Linear Least Squares Analysis with Excel
Given the data and plots (graph) in the spreadsheet,
Method I. The Functions for the Slope, Intercept and Correlation Coefficient.
The slope, the intercept, and the correlation coefficient can be directly called into
a cell with = sign like any other functions; i.e., they are readily available as functions.
(1) To find the slope of a least squares line,
=slope(known_y’s,known_x’s)
for example, =slope(c7:c11,b7:b11)
(2) To find the intercept of a least squares line, = intercept (known_y’s,known_x’s)
for example, = intercept (c7:c11,b7:b11)
(3) To find the correlation coefficient of a least squares line,
= correl (known_y’s,known_x’s)
for example, = correl (c7:c11,b7:b11)
Method II. Direct Addition of a Trend-line and Equation on the Graph.
(1) Right click on one of the data points to select a data series.
(2) Select Add Trend Line by left clicking on it.
(3) Select the Linear Trend (the first one).
(4) Mark Set the Intercept to force the intercept to be Zero (for spectrophotometric data).
Mark Display equation on the Chart & Display R-squared Value on the Chart.
(5) Click OK.
Method III. Regression with Analysis of Variance
(1)
(2)
(3)
(4)
(5)
Select the Chart, then Click on the Tools
Click on Add-Ins, then the select Analysis Toolpak.
Click on the spreadsheet, then click on Tools again.
Select Data Analysis then Regression. Click OK.
Provide cell addresses for the Input Y Range and Input X Range.
Then, mark an Output Range to a suitable cell address.
(6) Click OK for the details of the regression and analysis of the variance.
Sc_Excel_WS_02.doc (11/18/02, 2/14/03, MHK)