Download Analytical Chemistry Q&A: Titration, GC, and AAS Principles and more Exams Chemistry in PDF only on Docsity!
Calculate volume 0.2 NaOH and # equivalence points for titration of 25mL 0. H3PO4 - CORRECT ANSWER -2 eq points-
0.1M x 0.025L = 0.0025 mol H3PO
mol H3PO4 = mol added NaOH
0.0025 mol NaOH / 0.2 M = 0.0125 L NaOH added
Calculate equivalence point volumes for titration of 25.00 mL of 0.060 M HCl and 0.10 M H3PO4 with 0.075 M NaOH - CORRECT ANSWER -exp 1 calculations
find moles total acid,
response factor - CORRECT ANSWER -Coefficient that makes the relative response of a detector to analyte and the internal standard the same.
equation to find unknown amount analyte using RF - CORRECT ANSWER -(amount ethanol / amount IS) = (area ethanol / area IS) x RF
Equation for number of theoretical plates - CORRECT ANSWER -N = 5.55 x (tr^2 / w1/2^2)
HETP equation - CORRECT ANSWER -L / N
Principle components of a GC - CORRECT ANSWER -Mobile phase reservoir --> [Sample injector --> stationary phase --> Detector] --> readout
OVEN in brackets
Quantities on x and y axes in a chromatogram - CORRECT ANSWER -x axis - retention time (min)
y axis - detector response
All strong acids - CORRECT ANSWER -HCl, HBr, HI, HNO3, HClO4, H2SO
molecular weight and boiling point of ethanol - CORRECT ANSWER -46.07 g/mol
78.37 degrees
molecular weight and boiling point of 1-butanol - CORRECT ANSWER -74.12 g/mol
117.40 degrees C
Calculate RF for mixture containing
ethanol: 8.0 x 10^-5 M with an area of 122,
1-butanol:6.4 x 10^-5 M with an area of 172,000 - CORRECT ANSWER -1.
desirable qualities for IS in GC - CORRECT ANSWER -similar in structure to analyte but not present under analysis
2 advantages of using IS over a calibration curve - CORRECT ANSWER -1. any hard to reproduce procedure that's the same for both the unknown and IS shouldn't influence the determination
Planck's equation - CORRECT ANSWER -E = hv = hc/λ
What is quantization? - CORRECT ANSWER -a given molecule cannot absorb any and all incident light regardless of wavelength
the energy content of the light as determined by its frequency must exactly match the energy needed to raise it to one of its available electronic, rotational, or vibrational excited states
relationship between wavelength and frequency - CORRECT ANSWER -inverse
energy is directly proportional to frequency
115 mg Na per serving and 28g serving size:
calculate the chip sample weight that will give you a solution whose Na content falls within the desired 0.2-5.0 ppm range of your calibration curve - CORRECT ANSWER -5 ppm would be 0.122 g Na
see quiz 3 for math
Block diagram of a fluorescence spectrum - CORRECT ANSWER -Light source --> monochromator --> sample cell --> monochromator --> photodetector --> readout
Why does a fluorescence spectrometer have two monochromators? - CORRECT ANSWER -The first one selects for the optimum excitation wavelength and the second one separates the fluorescence signal into its different wavelengths
What values are on the x and y axis of a fluorescence spectrum? - CORRECT ANSWER -x axis: wavelength
y axis: fluorescence intensity
What values are on the x and y axis of a calibration curve for a fluorescence experiment? - CORRECT ANSWER -x axis: concentration
y axis: fluorescence intensity
What is the difference between an excitation spectrum and an emission spectrum? - CORRECT ANSWER -excitation spectrum - determines what wavelength produces maximum fluorescence signal for a sample
emission spectrum - identifies which wavelength are given off when sample returns to the ground state
Main difference in spectra for atomic emission vs molecular emission - CORRECT ANSWER -in atomic emission, emission occurs at only one specific wavelength because atoms only have electronic levels
in molecular emission, lots of wavelengths are emitted, we just use the maximum wavelength; each electronic state will have many excited states
