CWEA GRADE 1 LABORATORY ANALYST PRACTICE EXAM |2025-2026|
200 QUESTIONS WITH DETAILED ANSWER EXPLANATIONS ACTUAL
EXAM WITH CORRECT DETAILED ANSWERS WITH RATIONALES |A+
GRADED.
What does COLOR measure? - - ANS - -Amount of color units (CU) in a sample. Color
caused by natural metallic ions (Fe & Mg) & industrial wastes.
What is the test summary for COLOR? - - ANS - -Sample -> Tubes -> Compare to color
standards over light source
Which of the following techniques is used to isolate anionic surfactants (as MBAS)
from the sample matrix? - - ANS - -Extraction
In the cyanide determination, which one of the following is not an interference? - -
ANS - -Halogenated aromatics
Which of the following is not a major interference in phenol determination? - - ANS -
-Hydroxy derivatives of benzene
A freshly prepared sodium hydroxide (NaOH) solution is standardized against primary
standard potassium acid phthalate (KHC8H4O4). 0.8000 grams of potassium acid
phthalate was dissolved into 50 mL CO2-free water. 2-3 drops of phenolphthalein
were added. The sample was titrated to a faint pink endpoint with 22 mLs sodium
hydroxide. What is the normality of the sodium hydroxide? - - ANS - -0.178 N
What does an ICP source consist of? - - ANS - -A flowing stream of argon gas ionized
by an applied radio frequency
, In gas chromatography, electron capture detectors (ECD) are used to detect which of
the following compounds? - - ANS - -Chlorinated hydrocarbon pesticides
Why is methlyene chloride replaced by hexane in sample preparation for analyses
detected by GC electron capture detection (ECD)? - - ANS - -Chlorine compounds are
detected by ECD
Which of the following methods is used to determine pesticides? - - ANS - -EPA
Method 608
What analysis uses the purge and trap technique? - - ANS - -Volatile organic
compound analysis
The test for inhibitory residues on glassware and plastic ware determines the toxic or
stimulatory effects of dishwashing detergents used for bacterial analysis. Which
bacterial genera is used for this test? - - ANS - -Enterobacter
The Water Suitability Test (Test for Bacteriological Quality of Reagent Water)
determines the toxic or stimulatory effects of the distilled or deionized water system.
Which bacteria genera is used for this test? - - ANS - -Enterobacter
Short-term toxicity tests are inappropriate for: - - ANS - -determining chronic
toxicity.
Basic requirements for toxicity tests do not include: - - ANS - -documented re-use of
control test organisms.
200 QUESTIONS WITH DETAILED ANSWER EXPLANATIONS ACTUAL
EXAM WITH CORRECT DETAILED ANSWERS WITH RATIONALES |A+
GRADED.
What does COLOR measure? - - ANS - -Amount of color units (CU) in a sample. Color
caused by natural metallic ions (Fe & Mg) & industrial wastes.
What is the test summary for COLOR? - - ANS - -Sample -> Tubes -> Compare to color
standards over light source
Which of the following techniques is used to isolate anionic surfactants (as MBAS)
from the sample matrix? - - ANS - -Extraction
In the cyanide determination, which one of the following is not an interference? - -
ANS - -Halogenated aromatics
Which of the following is not a major interference in phenol determination? - - ANS -
-Hydroxy derivatives of benzene
A freshly prepared sodium hydroxide (NaOH) solution is standardized against primary
standard potassium acid phthalate (KHC8H4O4). 0.8000 grams of potassium acid
phthalate was dissolved into 50 mL CO2-free water. 2-3 drops of phenolphthalein
were added. The sample was titrated to a faint pink endpoint with 22 mLs sodium
hydroxide. What is the normality of the sodium hydroxide? - - ANS - -0.178 N
What does an ICP source consist of? - - ANS - -A flowing stream of argon gas ionized
by an applied radio frequency
, In gas chromatography, electron capture detectors (ECD) are used to detect which of
the following compounds? - - ANS - -Chlorinated hydrocarbon pesticides
Why is methlyene chloride replaced by hexane in sample preparation for analyses
detected by GC electron capture detection (ECD)? - - ANS - -Chlorine compounds are
detected by ECD
Which of the following methods is used to determine pesticides? - - ANS - -EPA
Method 608
What analysis uses the purge and trap technique? - - ANS - -Volatile organic
compound analysis
The test for inhibitory residues on glassware and plastic ware determines the toxic or
stimulatory effects of dishwashing detergents used for bacterial analysis. Which
bacterial genera is used for this test? - - ANS - -Enterobacter
The Water Suitability Test (Test for Bacteriological Quality of Reagent Water)
determines the toxic or stimulatory effects of the distilled or deionized water system.
Which bacteria genera is used for this test? - - ANS - -Enterobacter
Short-term toxicity tests are inappropriate for: - - ANS - -determining chronic
toxicity.
Basic requirements for toxicity tests do not include: - - ANS - -documented re-use of
control test organisms.
