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EXPERIMENT 6: ATOMIC EMISSION SPECTROSCOPY(AES)
Part I.
Measuring the Hydrogen Emission Spectrum
Part II.
An Application of AES; Determination of Sodium
Total Points
= 60 (5 notebook, 55 template)
Part I.
Measuring the Hydrogen Emission Spectrum
DATA
Table 1.
Hydrogen Emission Data
Spectroscope Data
Ocean Optics Spectrometer
Color
Wavelength, nm
violet
blue-green
red
A: Data Analysis
0.0
0.0
0.0
0.0
0.0
Slope:
R from slope:
y-intercept:
R from y-intercept:
λ
(nm)
(descending order)
Table 2.
Hypothesis #1; n
f
= 1; n
i
= 2, 3, 4, 5, 6
n
i
values
1/n
i
2
λ
(nm)
1/
λ
nm
-1
nm
-1
Is n
f
=1?
nm
-1
Hypothesis #1
:
n
f
(assumed) = 1; therefore n
i
= 2, 3, 4, 5, 6.
If the hypothesis is correct, a plot of
1/
λ
vs. 1/n
i
2
should be linear (good R
2
) and
the Rydberg constants
calculated from slope and the y-intercepts should be the same.
Calculate 1/
λ
and 1/n
i
2
, then plot the data
and include the equation and R
2
on the plot.
Compare the R values calculated from the slope and y-int.
Excel Help for Data in Tables 2, 3
& 4
1
. Column B: =1/(Click on column A
entry)^2, Enter. Copy and paste into
remaining cells.
2.
Column D: =1/(Click on Column C
entry), Enter. Copy and paste into
other cells.
3.
Format cells to desired number
of decimal places.
Highlight cells,
Format, Number, select number of
decimal places. A number that does
not fit the column width will show an
error and a number that is too smal
for the formatting will register as
zero. You also have the option to
write the number in scientific
notation.
4
.Plot 1/
λ
on the y-axis and 1/n
i
2
on
the x-axis.
Right click on any data
point and add a trendline.
In the
trendline help box, choose linear
type, and under the options tab,
click on the boxes in front of "displa
equation on chart" and "display R-
squared on chart". Right click on the
equation, choose "format data
labels" or "format trendline label"
and change the number properties
so that 5 sig figs are displayed.
(Failure to do this on each plot
will cost you a point!)
5.
From the Rydberg equation, you
know that the slope is equal to -R
and the y-intercept is equal to R/n
f
2
.
Calculate R both ways and
compare.
Report your results to 4
or 5 sig figs.
Use these in the data analysis.
Data here will autofill into the third
column of Tables 2-4
Hypothesis #2
:
n
f
(assumed) = 2; therefore n
i
= 3, 4, 5, 6, 7.
If the hypothesis is correct, a plot of
1/
λ
vs. 1/n
i
2
should be linear (good R
2
) and
the Rydberg constants calculated from slope
and the y-intercepts should be the same.
Calculate 1/
λ
and 1/n
i
2
, then plot the data and include the equation and R
2
on the plot.
Compare the R values calculated from the slope and y-int.
Put your plot of 1/
λ
vs 1/n
i
2
here. Make your plot big enough to cover this instruction box so that it is large
enought for someone else to read.