CWEA LAB ANALYST COMPLETE SET
An amperometric titration is often used when measuring - correct answer Residual chlorine
The most important reason for chlorinating effluent is - correct answer Disinfection
Chlorination serves primarily to destroy or deactivate disease-producing microorganisms
When wastewater samples are chlorinated and the pH is lowered - correct answer HCLO is
formed
Hypochlorous acid
Which of the following constituents is the best disinfecting agent? - correct answer HClO
What is most likely to interfere with the DPD test? - correct answer Oxidized manganese
How is N, N-diethyl-p-phenylenediamine more commonly represented? - correct answer DPD
The chlorine residual may be determined using the reagent - correct answer DPD
The quantity of chlorine that is converted to inert or less active forms of chlorine by substances
in wastewater - correct answer Total combined chlorine
Before you perform an amperometric titration for total residual chlornie, what two solutions
should be added to the sample? - correct answer Kl and acetate buffer
(Potassium iodide)
,When performing an amperometric titration for chlorine, how many milliliters of sample should
be analyzed? - correct answer 200 mL
When using a spectrophotometer to measure chlorine, what wave length of light should be
used? - correct answer 515 nm
An effluent with a high level of ammonia nitrogen has chlorine residual that is mostly - correct
answer Combined chlorine
The mercuric nitrate titration technique for measuring chloride is falling into disuse in the
laboratory because the: - correct answer technique is lengthy and requires highly skilled
instrument technicians to accurately analyze the samples.
Standard phenylarsine oxide solution (PAO): - correct answer should be handled with caution
because it is a severe poison.
Sample Protocol for chloride includes - correct answer glass or plastic container with no
preservative
Flow proportional sample. If total sample volume is 1 liter - correct answer 100ml
The incubator for the BOD determination should be monitored and recorded daily. The
incubator temperature should be: - correct answer 20 degrees +/-1 degree C
Laboratory data mistakes may be corrected by: - correct answer 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: - correct answer sample collector,
nature of sample, analyses to be performed, preservatives, condition of sample and sample
recipient.
,Hood flow should be monitored and documented at: - correct answer 100 linear feet per
minute
During an acid base titration, the titrant is added to the sample with a: - correct answer Buret
Separatory funnels are designed to facilitate liquid-liquid extractions. Liquid-liquid extraction
can be used to separate - correct answer 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
- correct answer 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? - correct answer 100 times higher
A pH measurement requires the following: - correct answer a voltmeter, glass pH electrode,
reference electrode, and temperature compensating device
Conductance measurements are temperature compensated to: - correct answer 25.0 C
The conductivity meter is calibrated with: - correct answer .0100 N potassium chloride standard
Alkalinity is reported as: - correct answer alkalinity, mg CaCO3/L
The hardness determination by EDTA titration measures: - correct answer Calcium and
Magnesium
The indicator for the hardness determination is: - correct answer eriochrome Black T
, EPA acceptable primary standards for the turbidity determination include: - correct answer
formazine only
COD - correct answer ((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: - correct answer determine the relative oxygen requirements
of wastewaters, effluents and polluted waters.
Sample pretreatment for the BOD determination includes - correct answer 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: - correct answer disinfection
Fecal coliform bacteria: - correct answer are bacteria found in the feces of warm blooded
animals.
The definition for the total coliform group is - correct answer 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: - correct answer a known error has occurred
Precision is measured by - correct answer analyzing replicate samples
Accuracy - correct answer The combination of bias and precision of an analytical procedure,
which reflects the closeness of a measured value to a true value
An amperometric titration is often used when measuring - correct answer Residual chlorine
The most important reason for chlorinating effluent is - correct answer Disinfection
Chlorination serves primarily to destroy or deactivate disease-producing microorganisms
When wastewater samples are chlorinated and the pH is lowered - correct answer HCLO is
formed
Hypochlorous acid
Which of the following constituents is the best disinfecting agent? - correct answer HClO
What is most likely to interfere with the DPD test? - correct answer Oxidized manganese
How is N, N-diethyl-p-phenylenediamine more commonly represented? - correct answer DPD
The chlorine residual may be determined using the reagent - correct answer DPD
The quantity of chlorine that is converted to inert or less active forms of chlorine by substances
in wastewater - correct answer Total combined chlorine
Before you perform an amperometric titration for total residual chlornie, what two solutions
should be added to the sample? - correct answer Kl and acetate buffer
(Potassium iodide)
,When performing an amperometric titration for chlorine, how many milliliters of sample should
be analyzed? - correct answer 200 mL
When using a spectrophotometer to measure chlorine, what wave length of light should be
used? - correct answer 515 nm
An effluent with a high level of ammonia nitrogen has chlorine residual that is mostly - correct
answer Combined chlorine
The mercuric nitrate titration technique for measuring chloride is falling into disuse in the
laboratory because the: - correct answer technique is lengthy and requires highly skilled
instrument technicians to accurately analyze the samples.
Standard phenylarsine oxide solution (PAO): - correct answer should be handled with caution
because it is a severe poison.
Sample Protocol for chloride includes - correct answer glass or plastic container with no
preservative
Flow proportional sample. If total sample volume is 1 liter - correct answer 100ml
The incubator for the BOD determination should be monitored and recorded daily. The
incubator temperature should be: - correct answer 20 degrees +/-1 degree C
Laboratory data mistakes may be corrected by: - correct answer 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: - correct answer sample collector,
nature of sample, analyses to be performed, preservatives, condition of sample and sample
recipient.
,Hood flow should be monitored and documented at: - correct answer 100 linear feet per
minute
During an acid base titration, the titrant is added to the sample with a: - correct answer Buret
Separatory funnels are designed to facilitate liquid-liquid extractions. Liquid-liquid extraction
can be used to separate - correct answer 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
- correct answer 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? - correct answer 100 times higher
A pH measurement requires the following: - correct answer a voltmeter, glass pH electrode,
reference electrode, and temperature compensating device
Conductance measurements are temperature compensated to: - correct answer 25.0 C
The conductivity meter is calibrated with: - correct answer .0100 N potassium chloride standard
Alkalinity is reported as: - correct answer alkalinity, mg CaCO3/L
The hardness determination by EDTA titration measures: - correct answer Calcium and
Magnesium
The indicator for the hardness determination is: - correct answer eriochrome Black T
, EPA acceptable primary standards for the turbidity determination include: - correct answer
formazine only
COD - correct answer ((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: - correct answer determine the relative oxygen requirements
of wastewaters, effluents and polluted waters.
Sample pretreatment for the BOD determination includes - correct answer 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: - correct answer disinfection
Fecal coliform bacteria: - correct answer are bacteria found in the feces of warm blooded
animals.
The definition for the total coliform group is - correct answer 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: - correct answer a known error has occurred
Precision is measured by - correct answer analyzing replicate samples
Accuracy - correct answer The combination of bias and precision of an analytical procedure,
which reflects the closeness of a measured value to a true value
