ChTLE 2024 Test Bank 7 (Instrumental Analysis)

All proteins absorb electromagnetic radiation of wavelength around 190 nm, which corresponds to a excitation in the protein molecule. In which region of the spectrum is this wavelength found?

a. X-ray

b. ultraviolet

c. Visible

d. Infrared

B.

Chromatography is used to:

a. Separate two or more compounds based on their polarities.

b. Separate two or more compounds based on their masses.

c. Separate two or more compounds based on how strongly they interact with other compounds.

d) all of the above.

D.

A food scientist has a sample of plant oil and wants to determine if the oil contains saturated or unsaturated fatty acids. Which of the following spectroscopic techniques would be most useful for this purpose?

a. ultraviolet spectroscopy

b. visible spectroscopy

c. infrared spectroscopy

d. mass spectroscopy

C.

The concentration at which the calibration curve departs from linearity by a specified amount.

a. Limit of Blank

b. Dynamic Range

c. Limit of Linearity

d. Limit of quantitation

C.

A graphical representation of measuring signal as a function of quantity of analyte.

a. Calibration curve

b. Quality Control Chart

c. Absorbance Chart

d. None of the above

A.

What is the path of light through a spectrophotometer?

a. meter, photodetector, filter, sample, light source

b. meter, filter sample, photodetector, light source

c. light source, filter, sample, photodetector, meter

d. light source, sample, filter, photodetector, meter

C.

With a "standard" sample with a known absorbance and concentration and a measured absorbance, it is easy to determine an unknown concentration of the same substance by.

a. Beer's Law

b. Beer and Lambert's Law

c. Law of mass conservation

d. none of the above

Beer's Law

The highest apparent analyte concentration expected to be found when replicates of a blank sample containing no analyte are tested.

a. Limit of Detection

b. Limit of Blank

c. Limit of Linearity

d. Limit of Quantitation

B.

Motion of the mobile phase through the stationary phase.

a. Elution

b. Retention time

c. Eluent

d. Elution time

A.

A phase in which the sample is dissolved may be gas, liquid, or supercritical fluid.

a. stationary phase

b. reverse phase

c. normal phase

d. mobile phase

D.

In spectrophotometric methods, the _________ isolates the specific spectrum line emitted by the light source through spectral dispersion.

a. monochromator

b. prism

c. sample compartment

d. detector

A.

In AAS method, If the sample concentration is too high to permit accurate analysis in linearity response range, there are alternatives that may help bring the absorbance into the optimum working range.

a. sample dilution

b. using an alternative wavelength having a lower absorptivity

c. reducing the path length by rotating the burner hand

d. All of the above

D.

A technique for separating mixtures into their components in order to analyze, identify, purify, and/or quantify the mixture or components.

a. Spectrocopy

b. Chromatography

c. Gravimetry

d. Titrimetry

B.

A "modified" stationary phase where polar solutes run fast i.e. reverse order.

a. Normal phase

b. Reverse phase

c. mobile phase

d. none of the above

B.

A graph showing the detector's response as a function of elution time: band's shapes, position, resolution.

a. monitor display

b. quality control chart

c. calibration curve

d. chromatogram

D.

The pH meter glass probe has two electrodes, one is a glass sensor electrode and the other is a _______electrode.

a. reference

b. anode

c. cathode

d. none of the above

A.

Conductivity could be determined using the distance between the electrodes and their surface area using Ohm's law but, for accuracy, a calibration is employed using _____ of well-known conductivity.

a. acid solution

b. basic solution

c. electrolytes

d. buffer solution

C.

The electrical conductivity of water is directly related to the concentration of dissolved ionized solids in the water or:

a. Total Suspended Solids

b. Total Dissolved Solids

c. Volatile Solids

d. Total Solids

B.

At 510 nm, the iron o-phenanthroline complex has a molar absorptivity of 1.2 x 10^4. What is the concentration of iron (in ppm) in a solution which gives an absorbance of 0.002 in a 1.00-cm path length cell?

a. 7.3 x 10-3 ppm

b.8.3 x 10-3 ppm

c. 9.3 x 10-3 ppm

d. 6.3x 10-3 ppm

C.

The light source used in the visible range to 340-1000 nm.

a. deuterium

b. nerst blower

c. tungsten

d. incandescent

C.

The % T of a solution in a 2.00 cm cell is 50. Calculate the %T of this solution in a 1.0 cm cell path length.

a. 71

b. 19

c. 27

d. 20

A.

An air sampling canister was evacuated by the local fire dep't and brought to the environmental lab for analysis. It was said that the sample was taken very near the site where a rusty 55-gal drum was found by some children. A reported unpleasant smell near the site was reported. Results of gravimetric analysis of the gas in the canister: C - 40%, H- 6.7% , O - 53.33%. What is the liquid in the drum?

a. CH2O

b. CH3OH

c. CH3CH2O

d. none of the above

A.

A comparison of measuring equipment against a standard instrument of higher accuracy to detect, correlate, adjust, rectify, and document the accuracy of the instrument being compared.

a. Verification

b. Validation

c. Calibration

d. none of the above

C.

The property of a result of a measurement whereby it can be related to appropriate standards, generally national or international standards, through an unbroken chain of comparisons.

a. Calibration

b. Accuracy

c. Precision

d. Traceability

D.