CWEA Lab Analyst Grade 1 Updated
Questions and Answers (2026/2027) |
Review Guide | Grade A+
• What increases concentration of chloride in wastewater -✓✓Chloride in human
diet and softeners flushed into sanitary sewer system
• 2 most prevalent methods of measuring chloride -✓✓argentometric and mercuric
nitrate
• Argentometric -✓✓Titration of sample with standard solution of silver nitrate
(AgNO3)
- Indicator: Chromate ions (CrO4)
- End point: reddish silver chromate
• Mercuric Nitrate -✓✓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 -✓✓Sulfide, bromide, orthophosphate
(over 30 ppm), and iodide
• Why does color change in water -✓✓Presence of decaying vegetable matter,
metal ions (ie. iron) or industrial and domestic pollution
• How is color measured -✓✓Measured using visual comparison method
• Visual comparison method -✓✓Sample compared to standards using matched
nessler tubes
- Standards prepared with solution containing cholorplatinate and cobaltous
chloride
• Standard units for color -✓✓One unit= color resulting from 1 mg of platinum/L
• 2 color reporting -✓✓True and Apparent
, • True color -✓✓Color from dissolved substances, determine using sample treated
to remove turbidity
• Apparent Color -✓✓Includes dissolved and suspended solids
• Conductivity -✓✓H2Os capability to pass electrical flow
• Conductivity of pure water -✓✓0
• Units of conductivity -✓✓micromhos/cm
• Temperature conductivity should be read at -✓✓25 degrees Celcius
• How is conductivity affected -✓✓Mobility of ions, conductivity is dependent on
viscosity
• Viscosity -✓✓A liquids ability to resist flow, higher the viscosity the lower the
flow
• Relationship of temperature and viscosity -✓✓Inverse
• Acid -✓✓A compound which liberates hydrogen ions and has a pH below 7.
• Alkalinity: -✓✓The measurement of a sample's capacity to neutralize acid.
• Alkalinity measures -✓✓The carbonate, bicarbonate, and hydroxide ion
concentration found in water
• Primary reason for measuring alkalinity -✓✓Used in control of many water and
wastewater unit processes
• How is alkalinity measured -✓✓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: -✓✓The pH is
greater than 8.3
Questions and Answers (2026/2027) |
Review Guide | Grade A+
• What increases concentration of chloride in wastewater -✓✓Chloride in human
diet and softeners flushed into sanitary sewer system
• 2 most prevalent methods of measuring chloride -✓✓argentometric and mercuric
nitrate
• Argentometric -✓✓Titration of sample with standard solution of silver nitrate
(AgNO3)
- Indicator: Chromate ions (CrO4)
- End point: reddish silver chromate
• Mercuric Nitrate -✓✓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 -✓✓Sulfide, bromide, orthophosphate
(over 30 ppm), and iodide
• Why does color change in water -✓✓Presence of decaying vegetable matter,
metal ions (ie. iron) or industrial and domestic pollution
• How is color measured -✓✓Measured using visual comparison method
• Visual comparison method -✓✓Sample compared to standards using matched
nessler tubes
- Standards prepared with solution containing cholorplatinate and cobaltous
chloride
• Standard units for color -✓✓One unit= color resulting from 1 mg of platinum/L
• 2 color reporting -✓✓True and Apparent
, • True color -✓✓Color from dissolved substances, determine using sample treated
to remove turbidity
• Apparent Color -✓✓Includes dissolved and suspended solids
• Conductivity -✓✓H2Os capability to pass electrical flow
• Conductivity of pure water -✓✓0
• Units of conductivity -✓✓micromhos/cm
• Temperature conductivity should be read at -✓✓25 degrees Celcius
• How is conductivity affected -✓✓Mobility of ions, conductivity is dependent on
viscosity
• Viscosity -✓✓A liquids ability to resist flow, higher the viscosity the lower the
flow
• Relationship of temperature and viscosity -✓✓Inverse
• Acid -✓✓A compound which liberates hydrogen ions and has a pH below 7.
• Alkalinity: -✓✓The measurement of a sample's capacity to neutralize acid.
• Alkalinity measures -✓✓The carbonate, bicarbonate, and hydroxide ion
concentration found in water
• Primary reason for measuring alkalinity -✓✓Used in control of many water and
wastewater unit processes
• How is alkalinity measured -✓✓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: -✓✓The pH is
greater than 8.3
