Lab Analyst Complete Set questions with verified detailed answers
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An amperometric titration is often used when measuring - ✔✔Residual chlorine
|| || || || || || || || || ||
The most important reason for chlorinating effluent is - ✔✔Disinfection
|| || || || || || || || ||
Chlorination serves primarily to destroy or deactivate disease-producing microorganisms
|| || || || || || || ||
When wastewater samples are chlorinated and the pH is lowered - ✔✔HCLO is formed
|| || || || || || || || || || || || ||
|| Hypochlorous acid ||
Which of the following constituents is the best disinfecting agent? - ✔✔HClO
|| || || || || || || || || || ||
What is most likely to interfere with the DPD test? - ✔✔Oxidized manganese
|| || || || || || || || || || || ||
How is N, N-diethyl-p-phenylenediamine more commonly represented? - ✔✔DPD
|| || || || || || || ||
The chlorine residual may be determined using the reagent - ✔✔DPD
|| || || || || || || || || ||
The quantity of chlorine that is converted to inert or less active forms of chlorine by substances in
|| || || || || || || || || || || || || || || || || ||
wastewater - ✔✔Total combined chlorine || || || ||
Before you perform an amperometric titration for total residual chlornie, what two solutions
|| || || || || || || || || || || || ||
should be added to the sample? - ✔✔Kl and acetate buffer
|| || || || || || || || || ||
(Potassium iodide) ||
When performing an amperometric titration for chlorine, how many milliliters of sample should
|| || || || || || || || || || || || ||
be analyzed? - ✔✔200 mL
|| || || ||
,When using a spectrophotometer to measure chlorine, what wave length of light should be used? -
|| || || || || || || || || || || || || || ||
✔✔515 nm
|| ||
An effluent with a high level of ammonia nitrogen has chlorine residual that is mostly -
|| || || || || || || || || || || || || || || ||
✔✔Combined chlorine ||
The mercuric nitrate titration technique for measuring chloride is falling into disuse in the
|| || || || || || || || || || || || || ||
laboratory because the: - ✔✔technique is lengthy and requires highly skilled instrument
|| || || || || || || || || || || ||
technicians to accurately analyze the samples. || || || || ||
Standard phenylarsine oxide solution (PAO): - ✔✔should be handled with caution because it is a
|| || || || || || || || || || || || || || ||
severe poison. ||
Sample Protocol for chloride includes - ✔✔glass or plastic container with no preservative
|| || || || || || || || || || || ||
Flow proportional sample. If total sample volume is 1 liter - ✔✔100ml
|| || || || || || || || || || ||
The incubator for the BOD determination should be monitored and recorded daily. The incubator
|| || || || || || || || || || || || || ||
temperature should be: - ✔✔20 degrees +/-1 degree C || || || || || || || ||
Laboratory data mistakes may be corrected by: - ✔✔lining out the mistake with pen and writing
|| || || || || || || || || || || || || || || ||
the correct answer to the side of the first with analyst initials and date
|| || || || || || || || || || || || ||
The sample receiving log must record time and date sampled: - ✔✔sample collector, nature of
|| || || || || || || || || || || || || || ||
sample, analyses to be performed, preservatives, condition of sample and sample recipient.
|| || || || || || || || || || ||
Hood flow should be monitored and documented at: - ✔✔100 linear feet per minute
|| || || || || || || || || || || || ||
During an acid base titration, the titrant is added to the sample with a: - ✔✔Buret
|| || || || || || || || || || || || || || ||
,Separatory funnels are designed to facilitate liquid-liquid extractions. Liquid-liquid extraction can
|| || || || || || || || || ||
be used to separate - ✔✔organic analytes from the water by partitioning them into an organic
|| || || || || || || || || || || || || || || || ||
solvent
At a given temperature the intensity of the acidic or basic character of a solution is indicated by -
|| || || || || || || || || || || || || || || || || || ||
✔✔pH or Hydrogen ion activity || || || ||
A solution with a pH of 5 has a concentration of hydrogen ions that is how many times higher
|| || || || || || || || || || || || || || || || || || ||
than a solution with a pH if 7? - ✔✔100 times higher
|| || || || || || || || || || ||
A pH measurement requires the following: - ✔✔a voltmeter, glass pH electrode, reference
|| || || || || || || || || || || || ||
electrode, and temperature compensating device || || || ||
Conductance measurements are temperature compensated to: - ✔✔25.0 C || || || || || || || ||
The conductivity meter is calibrated with: - ✔✔.0100 N potassium chloride standard
|| || || || || || || || || || ||
Alkalinity is reported as: - ✔✔alkalinity, mg CaCO3/L || || || || || || ||
The hardness determination by EDTA titration measures: - ✔✔Calcium and Magnesium
|| || || || || || || || || ||
The indicator for the hardness determination is: - ✔✔eriochrome Black T
|| || || || || || || || || ||
EPA acceptable primary standards for the turbidity determination include: - ✔✔formazine only
|| || || || || || || || || || ||
COD - ✔✔((Blank-Sample) x M x 8000))/ml Sample
|| || || || || || ||
, The Biochemical Oxygen Demand determination is an empirical test in which standardized
|| || || || || || || || || || || ||
laboratory procedures are used to: - ✔✔determine the relative oxygen requirements of
|| || || || || || || || || || || ||
wastewaters, effluents and polluted waters. || || || ||
Sample pretreatment for the BOD determination includes - ✔✔assuring that the samples are
|| || || || || || || || || || || || ||
neutralized to a pH range between 6.5 and 7.5 and that any residual chlorine has been
|| || || || || || || || || || || || || || || ||
dechlorinated
The process designed to kill most microorganisms in wastewater, including essentially all
|| || || || || || || || || || || ||
pathogenic bacteria is called: - ✔✔disinfection || || || || ||
Fecal coliform bacteria: - ✔✔are bacteria found in the feces of warm blooded animals.
|| || || || || || || || || || || || ||
The definition for the total coliform group is - ✔✔all of the aerobic and facultative anaerobic,
|| || || || || || || || || || || || || || || ||
gram-negative, non-spore-forming rod shaped bacteria that ferment lactose in 24-48 hours at 35 C || || || || || || || || || || || || ||
Laboratory test results for an individual environmental sample within an analytical batch may be
|| || || || || || || || || || || || || ||
rejected when: - ✔✔a known error has occurred
|| || || || || || ||
Precision is measured by - ✔✔analyzing replicate samples
|| || || || || || ||
Accuracy - ✔✔The combination of bias and precision of an analytical procedure, which reflects
|| || || || || || || || || || || || || ||
the closeness of a measured value to a true value
|| || || || || || || || ||
Bias - ✔✔Consistant deviation of measured values from the true value caused by systematic
|| || || || || || || || || || || || || ||
errors in a procedure || || ||
Precision - ✔✔Measure the degree of agreement among replicate analyses of a sample usually
|| || || || || || || || || || || || || ||
expressed as the standard deviation. || || || ||
|| || || || || || || ||
An amperometric titration is often used when measuring - ✔✔Residual chlorine
|| || || || || || || || || ||
The most important reason for chlorinating effluent is - ✔✔Disinfection
|| || || || || || || || ||
Chlorination serves primarily to destroy or deactivate disease-producing microorganisms
|| || || || || || || ||
When wastewater samples are chlorinated and the pH is lowered - ✔✔HCLO is formed
|| || || || || || || || || || || || ||
|| Hypochlorous acid ||
Which of the following constituents is the best disinfecting agent? - ✔✔HClO
|| || || || || || || || || || ||
What is most likely to interfere with the DPD test? - ✔✔Oxidized manganese
|| || || || || || || || || || || ||
How is N, N-diethyl-p-phenylenediamine more commonly represented? - ✔✔DPD
|| || || || || || || ||
The chlorine residual may be determined using the reagent - ✔✔DPD
|| || || || || || || || || ||
The quantity of chlorine that is converted to inert or less active forms of chlorine by substances in
|| || || || || || || || || || || || || || || || || ||
wastewater - ✔✔Total combined chlorine || || || ||
Before you perform an amperometric titration for total residual chlornie, what two solutions
|| || || || || || || || || || || || ||
should be added to the sample? - ✔✔Kl and acetate buffer
|| || || || || || || || || ||
(Potassium iodide) ||
When performing an amperometric titration for chlorine, how many milliliters of sample should
|| || || || || || || || || || || || ||
be analyzed? - ✔✔200 mL
|| || || ||
,When using a spectrophotometer to measure chlorine, what wave length of light should be used? -
|| || || || || || || || || || || || || || ||
✔✔515 nm
|| ||
An effluent with a high level of ammonia nitrogen has chlorine residual that is mostly -
|| || || || || || || || || || || || || || || ||
✔✔Combined chlorine ||
The mercuric nitrate titration technique for measuring chloride is falling into disuse in the
|| || || || || || || || || || || || || ||
laboratory because the: - ✔✔technique is lengthy and requires highly skilled instrument
|| || || || || || || || || || || ||
technicians to accurately analyze the samples. || || || || ||
Standard phenylarsine oxide solution (PAO): - ✔✔should be handled with caution because it is a
|| || || || || || || || || || || || || || ||
severe poison. ||
Sample Protocol for chloride includes - ✔✔glass or plastic container with no preservative
|| || || || || || || || || || || ||
Flow proportional sample. If total sample volume is 1 liter - ✔✔100ml
|| || || || || || || || || || ||
The incubator for the BOD determination should be monitored and recorded daily. The incubator
|| || || || || || || || || || || || || ||
temperature should be: - ✔✔20 degrees +/-1 degree C || || || || || || || ||
Laboratory data mistakes may be corrected by: - ✔✔lining out the mistake with pen and writing
|| || || || || || || || || || || || || || || ||
the correct answer to the side of the first with analyst initials and date
|| || || || || || || || || || || || ||
The sample receiving log must record time and date sampled: - ✔✔sample collector, nature of
|| || || || || || || || || || || || || || ||
sample, analyses to be performed, preservatives, condition of sample and sample recipient.
|| || || || || || || || || || ||
Hood flow should be monitored and documented at: - ✔✔100 linear feet per minute
|| || || || || || || || || || || || ||
During an acid base titration, the titrant is added to the sample with a: - ✔✔Buret
|| || || || || || || || || || || || || || ||
,Separatory funnels are designed to facilitate liquid-liquid extractions. Liquid-liquid extraction can
|| || || || || || || || || ||
be used to separate - ✔✔organic analytes from the water by partitioning them into an organic
|| || || || || || || || || || || || || || || || ||
solvent
At a given temperature the intensity of the acidic or basic character of a solution is indicated by -
|| || || || || || || || || || || || || || || || || || ||
✔✔pH or Hydrogen ion activity || || || ||
A solution with a pH of 5 has a concentration of hydrogen ions that is how many times higher
|| || || || || || || || || || || || || || || || || || ||
than a solution with a pH if 7? - ✔✔100 times higher
|| || || || || || || || || || ||
A pH measurement requires the following: - ✔✔a voltmeter, glass pH electrode, reference
|| || || || || || || || || || || || ||
electrode, and temperature compensating device || || || ||
Conductance measurements are temperature compensated to: - ✔✔25.0 C || || || || || || || ||
The conductivity meter is calibrated with: - ✔✔.0100 N potassium chloride standard
|| || || || || || || || || || ||
Alkalinity is reported as: - ✔✔alkalinity, mg CaCO3/L || || || || || || ||
The hardness determination by EDTA titration measures: - ✔✔Calcium and Magnesium
|| || || || || || || || || ||
The indicator for the hardness determination is: - ✔✔eriochrome Black T
|| || || || || || || || || ||
EPA acceptable primary standards for the turbidity determination include: - ✔✔formazine only
|| || || || || || || || || || ||
COD - ✔✔((Blank-Sample) x M x 8000))/ml Sample
|| || || || || || ||
, The Biochemical Oxygen Demand determination is an empirical test in which standardized
|| || || || || || || || || || || ||
laboratory procedures are used to: - ✔✔determine the relative oxygen requirements of
|| || || || || || || || || || || ||
wastewaters, effluents and polluted waters. || || || ||
Sample pretreatment for the BOD determination includes - ✔✔assuring that the samples are
|| || || || || || || || || || || || ||
neutralized to a pH range between 6.5 and 7.5 and that any residual chlorine has been
|| || || || || || || || || || || || || || || ||
dechlorinated
The process designed to kill most microorganisms in wastewater, including essentially all
|| || || || || || || || || || || ||
pathogenic bacteria is called: - ✔✔disinfection || || || || ||
Fecal coliform bacteria: - ✔✔are bacteria found in the feces of warm blooded animals.
|| || || || || || || || || || || || ||
The definition for the total coliform group is - ✔✔all of the aerobic and facultative anaerobic,
|| || || || || || || || || || || || || || || ||
gram-negative, non-spore-forming rod shaped bacteria that ferment lactose in 24-48 hours at 35 C || || || || || || || || || || || || ||
Laboratory test results for an individual environmental sample within an analytical batch may be
|| || || || || || || || || || || || || ||
rejected when: - ✔✔a known error has occurred
|| || || || || || ||
Precision is measured by - ✔✔analyzing replicate samples
|| || || || || || ||
Accuracy - ✔✔The combination of bias and precision of an analytical procedure, which reflects
|| || || || || || || || || || || || || ||
the closeness of a measured value to a true value
|| || || || || || || || ||
Bias - ✔✔Consistant deviation of measured values from the true value caused by systematic
|| || || || || || || || || || || || || ||
errors in a procedure || || ||
Precision - ✔✔Measure the degree of agreement among replicate analyses of a sample usually
|| || || || || || || || || || || || || ||
expressed as the standard deviation. || || || ||
