Problem Set 3: Standard Addition, Internal Standard, and Curvilinear Regressions
1. Standard Addition: Miller & Miller, Chapter 5, Problem
6: Show all calculations clearly by hand, clearly organize spreadsheet,
clearly show sample and predicted responses both on graph and in spreadsheet.
Clearly show all uncertainty calculations to include formulas, substitutions
and units with final answers.
2. Standard Addition: Harris, Chapter 5, Problem 19:
Show all calculations clearly by hand, clearly organize spreadsheet, clearly
show sample and predicted responses both on graph and in spreadsheet.
Clearly show all uncertainty calculations to include formulas, substitutions
and units with final answers. Be sure to calculate all concentrations
correctly.
3. Internal Standard: Harris, Chapter 5, Problem 23:
Show all formulas and calculations clearly by hand and in spreadsheet.
Be sure to calculate concentrations correctly.
4. Curvilinear Regression: Table 1 lists the
data obtained from the calibration of an atomic emission spectrometer's
response for a range of alkali ion concentrations.
|
Concentration (ppm)
|
Counts/msec
|
|
0.2
|
0.8
|
|
0.5
|
1.3
|
|
1.0
|
2.2
|
|
2.0
|
3.7
|
|
3.0
|
5.1
|
|
4.0
|
6.5
|
|
5.0
|
7.8
|
|
6.0
|
8.9
|
|
7.0
|
9.9
|
|
8.0
|
10.5
|
|
9.0
|
10.8
|
|
10.0
|
11.0
|
-
Using all points, conduct a 2nd order fit of these data; plot the predicted
curve, the data points, and write the equation for the predicted curve
that includes appropriate units.
-
For an unknown analysis that gave a reading of 10.6 counts/msec, determine
the unknown's concentation. Show all calculations on a separate sheet
of paper; graphically illustrate this on your calibration plot.
-
Using all points, conduct a 1st order fit of the data, show the equation,
and compare the Coefficients of Determination for the 1st and 2nd order
fits. State what percent of the overall variability is accounted
for in each of these fits