Instrumental Analysis Midterm 1 (Ch 1,6,7,13,14)
questions with verified answers
A grating is 25 mm long and has 600 lines/mm. Calculate:
a) the distance between grooves
b) the total number of grooves for the grating
c) the resolving power assuming second order diffraction
d) assuming a center wavelength of 550, the minimum wavelength
separation associated with this resolving power Ans✓✓✓ See 3-5.
A grating monochromator with a reciprocal linear dispersion of 1.2
nm/mm is to be used to separate the sodium lines at 588.9950 nm and
589.5924 nm. In theory, what slit width would be required? Ans✓✓✓
See example 7-2.
A grating reflects first order light at 500 nm. The difference in two
wavelengths that can be detected using this grating is 0.010 nm. What
is the resolution of this monochromator? (note that resolution is a
unitless quantity) Ans✓✓✓ Resolution = lambda/delta lambda = 500
nm/0.010 nm = 50,000
A least squares analysis of calibration data for the determination of
lead based on its flame emission yielded the equation
S= 1.12Cpb + 0.312
where Cpb is the lead concentration in ppm and S is a measure of the
relative intensity of the lead emission line.
, Concentration (ppm Pb): 10.0, 1.00, 0.00
# of Replications: 10, 10, 24
Mean Value of S: 11.62, 1.12, 0.0296
s: 0.15, 0.025, 0.0082
Calculate:
a) the calibration sensitivity
b) the analytical sensitivity at 1 and 10 ppm of Pb
c) the detection limit Ans✓✓✓ See example 1-2.
A particular method for the analysis of copper yields the results that are
low by 0.5 mg. What will be the percent relative error due to this
source is the weight of copper in a sample is...
a) 25 mg
d) 500 mg Ans✓✓✓ See a 1-3.
A solution that was 4.14x10-3 M in X had a transmittance of 0.126
when measured in a 2.00 cm cell. What concentration of X would be
required for the transmittance to be increased by a factor of 3 when a
1.00 cm cell was used? Ans✓✓✓ See 6-18.
An echellette grating that contains 1450 blazes/mm was irradiated with
a polychromatic beam at an incident angle 48 degrees to the grating
questions with verified answers
A grating is 25 mm long and has 600 lines/mm. Calculate:
a) the distance between grooves
b) the total number of grooves for the grating
c) the resolving power assuming second order diffraction
d) assuming a center wavelength of 550, the minimum wavelength
separation associated with this resolving power Ans✓✓✓ See 3-5.
A grating monochromator with a reciprocal linear dispersion of 1.2
nm/mm is to be used to separate the sodium lines at 588.9950 nm and
589.5924 nm. In theory, what slit width would be required? Ans✓✓✓
See example 7-2.
A grating reflects first order light at 500 nm. The difference in two
wavelengths that can be detected using this grating is 0.010 nm. What
is the resolution of this monochromator? (note that resolution is a
unitless quantity) Ans✓✓✓ Resolution = lambda/delta lambda = 500
nm/0.010 nm = 50,000
A least squares analysis of calibration data for the determination of
lead based on its flame emission yielded the equation
S= 1.12Cpb + 0.312
where Cpb is the lead concentration in ppm and S is a measure of the
relative intensity of the lead emission line.
, Concentration (ppm Pb): 10.0, 1.00, 0.00
# of Replications: 10, 10, 24
Mean Value of S: 11.62, 1.12, 0.0296
s: 0.15, 0.025, 0.0082
Calculate:
a) the calibration sensitivity
b) the analytical sensitivity at 1 and 10 ppm of Pb
c) the detection limit Ans✓✓✓ See example 1-2.
A particular method for the analysis of copper yields the results that are
low by 0.5 mg. What will be the percent relative error due to this
source is the weight of copper in a sample is...
a) 25 mg
d) 500 mg Ans✓✓✓ See a 1-3.
A solution that was 4.14x10-3 M in X had a transmittance of 0.126
when measured in a 2.00 cm cell. What concentration of X would be
required for the transmittance to be increased by a factor of 3 when a
1.00 cm cell was used? Ans✓✓✓ See 6-18.
An echellette grating that contains 1450 blazes/mm was irradiated with
a polychromatic beam at an incident angle 48 degrees to the grating
