| Enter x and y data in the
text area. Data will
be plotted as they are entered along with
a
linear least-squares fit. |
The straight line can be
adjusted manually by positioning the
cursor toward either end of the line, and
clicking and dragging, will allow that
end to move. Clicking toward the middle
moves the whole line up or down. |
The least-squares fit
minimizes the residual standard deviation
based on the sum of the squares of the
deviations between the fit and the data. |
Exercise.
The following concentration vs. absorbance data
were collected for a dye. Plot a Beer's Law plot
of these data and estimate the extinction
coefficient, given that the path length of the
sample was 1.17 cm. (You can copy the data from
the table and paste it into the applet data
area.)
| |
|
|
| Concentration(M) |
Absorbance |
|
| |
| 0.000000 |
0.000 |
|
| 0.000020 |
0.150 |
|
| 0.000040 |
0.239 |
|
| 0.000060 |
0.350 |
|
| 0.000080
|
0.480 |
|
| 0.000100
|
0.580 |
|
A
solution of dye with an unknown concentration was
found to have an absorbance of 0.325. What is the
concentration of dye in the solution? (You can
use the slope and intercept to calculate a value,
or you can click on the graph and move the mouse
to where the best-fit line has an absorbance
value of 0.325. Be careful not to move the fit
line!)
|