CWEA LABORATORY ANALYST EXAM ALL GRADES 2025/2026
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Chloride - (ANSWERS)- Major anion found in many natural waters
- Can impart salty taste in H2O
What increases concentration of chloride in wastewater - (ANSWERS)Chloride in
human diet and softeners flushed into sanitary sewer system
2 most prevalent methods of measuring chloride - (ANSWERS)argentometric and
mercuric nitrate
Argentometric - (ANSWERS)Titration of sample with standard solution of silver
nitrate (agno3)
- Indicator: Chromate ions (cro4)
- End point: reddish silver chromate
Mercuric Nitrate - (ANSWERS)Titration with standard mercuric nitrate solution
-ph must be adjusted between 2.3 and 2.8
- Indicator: Diphenyl carbazone
- End point: Change from blue to purple in presence of mercury
Interference of Mercuric Nitrate Method - (ANSWERS)Sulfide, bromide,
orthophosphate (over 30 ppm), and iodide
Why does color change in water - (ANSWERS)Presence of decaying vegetable
matter, metal ions (ie. Iron) or industrial and domestic pollution
How is color measured - (ANSWERS)Measured using visual comparison method
Visual comparison method - (ANSWERS)Sample compared to standards using
matched nessler tubes
, CWEA LABORATORY ANALYST EXAM ALL GRADES 2025/2026
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- Standards prepared with solution containing cholorplatinate and cobaltous chloride
Standard units for color - (ANSWERS)One unit= color resulting from 1 mg of
platinum/L
2 color reporting - (ANSWERS)True and Apparent
True color - (ANSWERS)Color from dissolved substances, determine using sample
treated to remove turbidity
Apparent Color - (ANSWERS)Includes dissolved and suspended solids
Conductivity - (ANSWERS)H2Os capability to pass electrical flow
Conductivity of pure water - (ANSWERS)0
Units of conductivity - (ANSWERS)micromhos/cm
Temperature conductivity should be read at - (ANSWERS)25 degrees Celcius
How is conductivity affected - (ANSWERS)Mobility of ions, conductivity is
dependent on viscosity
Viscosity - (ANSWERS)A liquids ability to resist flow, higher the viscosity the
lower the flow
Relationship of temperature and viscosity - (ANSWERS)Inverse
Acid - (ANSWERS)A compound which liberates hydrogen ions and has a ph below
, CWEA LABORATORY ANALYST EXAM ALL GRADES 2025/2026
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WITH A STUDY GUIDE
7.
Alkalinity: - (ANSWERS)The measurement of a sample's capacity to neutralize
acid.
Alkalinity measures - (ANSWERS)The carbonate, bicarbonate, and hydroxide ion
concentration found in water
Primary reason for measuring alkalinity - (ANSWERS)Used in control of many
water and wastewater unit processes
How is alkalinity measured - (ANSWERS)Titration of a sample with a standard
solution of either sulfuric acid or hydrochloric acid to predetermined ph endpoint
The phenolphthalein alkalinity of a water sample is zero if: - (ANSWERS)The ph is
greater than 8.3
Atomic Weight: - (ANSWERS)The sum of the number of protons and the number of
neutrons in the nucleus of an atom.
Atomic weights of elements are found on periodic tables.
Base: - (ANSWERS)A compound which liberates hydroxide ions and has a ph
above 7.
Biochemical Oxygen Demand (BOD): - (ANSWERS)The quantity of oxygen
utilized in the biochemical oxidation of organic
Matter under standard laboratory procedures for five days at 20° Centigrade, usually
expressed as a
Concentration (e.g., mg/L). BOD measurements are used to indicate the organic
BANK | ACCURATE REAL EXAM VERSIONS | CURRENTLY TESTING
WITH A STUDY GUIDE
Chloride - (ANSWERS)- Major anion found in many natural waters
- Can impart salty taste in H2O
What increases concentration of chloride in wastewater - (ANSWERS)Chloride in
human diet and softeners flushed into sanitary sewer system
2 most prevalent methods of measuring chloride - (ANSWERS)argentometric and
mercuric nitrate
Argentometric - (ANSWERS)Titration of sample with standard solution of silver
nitrate (agno3)
- Indicator: Chromate ions (cro4)
- End point: reddish silver chromate
Mercuric Nitrate - (ANSWERS)Titration with standard mercuric nitrate solution
-ph must be adjusted between 2.3 and 2.8
- Indicator: Diphenyl carbazone
- End point: Change from blue to purple in presence of mercury
Interference of Mercuric Nitrate Method - (ANSWERS)Sulfide, bromide,
orthophosphate (over 30 ppm), and iodide
Why does color change in water - (ANSWERS)Presence of decaying vegetable
matter, metal ions (ie. Iron) or industrial and domestic pollution
How is color measured - (ANSWERS)Measured using visual comparison method
Visual comparison method - (ANSWERS)Sample compared to standards using
matched nessler tubes
, CWEA LABORATORY ANALYST EXAM ALL GRADES 2025/2026
BANK | ACCURATE REAL EXAM VERSIONS | CURRENTLY TESTING
WITH A STUDY GUIDE
- Standards prepared with solution containing cholorplatinate and cobaltous chloride
Standard units for color - (ANSWERS)One unit= color resulting from 1 mg of
platinum/L
2 color reporting - (ANSWERS)True and Apparent
True color - (ANSWERS)Color from dissolved substances, determine using sample
treated to remove turbidity
Apparent Color - (ANSWERS)Includes dissolved and suspended solids
Conductivity - (ANSWERS)H2Os capability to pass electrical flow
Conductivity of pure water - (ANSWERS)0
Units of conductivity - (ANSWERS)micromhos/cm
Temperature conductivity should be read at - (ANSWERS)25 degrees Celcius
How is conductivity affected - (ANSWERS)Mobility of ions, conductivity is
dependent on viscosity
Viscosity - (ANSWERS)A liquids ability to resist flow, higher the viscosity the
lower the flow
Relationship of temperature and viscosity - (ANSWERS)Inverse
Acid - (ANSWERS)A compound which liberates hydrogen ions and has a ph below
, CWEA LABORATORY ANALYST EXAM ALL GRADES 2025/2026
BANK | ACCURATE REAL EXAM VERSIONS | CURRENTLY TESTING
WITH A STUDY GUIDE
7.
Alkalinity: - (ANSWERS)The measurement of a sample's capacity to neutralize
acid.
Alkalinity measures - (ANSWERS)The carbonate, bicarbonate, and hydroxide ion
concentration found in water
Primary reason for measuring alkalinity - (ANSWERS)Used in control of many
water and wastewater unit processes
How is alkalinity measured - (ANSWERS)Titration of a sample with a standard
solution of either sulfuric acid or hydrochloric acid to predetermined ph endpoint
The phenolphthalein alkalinity of a water sample is zero if: - (ANSWERS)The ph is
greater than 8.3
Atomic Weight: - (ANSWERS)The sum of the number of protons and the number of
neutrons in the nucleus of an atom.
Atomic weights of elements are found on periodic tables.
Base: - (ANSWERS)A compound which liberates hydroxide ions and has a ph
above 7.
Biochemical Oxygen Demand (BOD): - (ANSWERS)The quantity of oxygen
utilized in the biochemical oxidation of organic
Matter under standard laboratory procedures for five days at 20° Centigrade, usually
expressed as a
Concentration (e.g., mg/L). BOD measurements are used to indicate the organic
