Description
D Question 2
3.33 pts
In the spectrophotometric analysis of iron, the linear
calibration curve had a slope of 10,300 + 800 AU-M-1 and a
zero intercept. A solution of unknown iron concentration
produced an absorbance of 0.52 +0.04 AU. Based on these
data, the unknown concentration is determined to be
5.05×10-5 M. What is the uncertainty in the concentration?
+ 0.1 M M
+ 4 x 10-6 M
4 x
+ 6 x 10-7 M
+ 6 x 10-6 M
Question 3
3.33 pts
The confidence interval for a set of measurements represents for a defined confidence level that
the results from two different methods will agree with each other.
the variances of two different methods will agree with each other.
the true value lies within a certain range about the mean value.
an experimental value lies within a certain range about the mean value.
a
D
Question 4
3.33 pts
Systematic errors …
lead to bias in the results
have a definite value
are of the same magnitude for replicate measurements made the same way
all the above
has an assignable cause
Question 5
3.33 pts
The standard deviation in a method for the determination of carbon dioxide in automotive
exhaust gases has been found to be 0.08 ppm based on extensive past analysis. Estimate the
90% confidence interval for a triplicate analysis.
+/-0.36
+/- 0.56
+/- 0.76
+/- 0.16
Question 9
3.33 pts
A least squares analysis of calibration data for the determination of Calcium in a sports drink
yielded the following equation Signal = 1.12 Cca +0.312.
The following replicate data were obtained
Conc of Ca # of replicates Mean
Std Dev
10.0
10
11.62
0.15
1.00
10
1.12
0.005
0.000
24
0.0296
0.0082 This is the blank!
Calculate the limit of detection
7.5
0.022
1.12
0.073
Question 11
3.33 pts
Volts
0.350
M
0.325
??
W
0.300
Time (seconds)
Signal
Noise
S/N
Estimate the signal to noise ratio from the figure to the left.
50
2.5
5.0
25
Question 12
3.33 pts
If the signal-to-noise ratio for a signal is 4 after 100 data points have been averaged, how many
points should be collected to ensure a S/N of 8?
400
600
300
0 0
200
Question 13
3.33 pts
There are four types of instrumental noise, which noise source has a 1/f power spectral density?
Environmental Noise
Shot Noise
Flicker Noise
Johnson Noise
Question 14
3.33 pts
There are four types of instrumental noise, which is a quantum limited noise associated with
electrons and photons?
Environmental Noise
Shot Noise
Johnson Noise
Flicker Noise
Question 15
3.33 pts
Random noise can be eliminated by ensemble averaging because
both the signal and the noise are uncorrelated.
the signal is correlated and the noise is uncorrelated
the signal is uncorrelated and the noise is correlated
the signal and noise are correlated
Question 17
3.33 pts
The bending of light toward the normal as light strikes an interface passing obliquely through the
interface between one medium and another or through a medium of varying density. This
statement best describes
Refraction
Diffraction
Reflection
Scattering
Question 22
3.33 pts
Which combination of grating groove density and spectrometer focal length would yield the
highest resolution?
120 grooves/mm and 1.2m
1200 grooves/mm and 1.2 m
120 grooves/mm and 0.12m
1200 grooves/mm and 0.12m
Question 25
3.33 pts
The following statement best describes what type of detector: “A very sensitive device in which
electrons emitted from the photosensitive surface strike a second surface called a dynode, which
is positive with respect to the photosensitive detector, resulting in gain.”
photo cell
PDA
CCD
Oo
PMT
Question 7
3.33 pts
Which of the following are common figures of merit?
all are figures of merit
standard deviation
cost per sample
selectivity
sensitivity
Question 7
3.33 pts
Which of the following are common figures of merit?
all are figures of merit
standard deviation
cost per sample
selectivity
sensitivity
Question 8
3.33 pts
Which figure of merit best describes the minimum detectable
amount of an analyte?
0 S/N
???
OLDR
LOD
Question 20
3.33 pts
We discussed several phenomena when light strikes a sample.
Which statement best describes what can happen when light
strikes a sample?
Light can be transmitted, absorbed, or reflected.
Light can be transmitted or absorbed.
Light can be transmitted, absorbed, reflected, or scattered.
Light can be absorbed.
D
Question 21
3.33 pts
Which series best reflects a single channel detector, a
multichannel high light level detector and a multichannel low light
level detector
CCD, PDA, Photocell
PMT, PDA, CCD
PMT, CCD, PDA
Photocell, PMT, PDA
Question 24
3.33 pts
Which instrument combination would be appropriate for a
spectrometer to measure absorbance in the 200-360 nm range?
Source, Sample Holder
Tungsten bulb, Quartz cuvette
Deuterium lamp, Quartz cuvette
Nernst glower, NaCl salt plates
O
Deuterium lamp, Plastic cuvette
Purchase answer to see full
attachment
