CWEA GRADE I LABORATORY ANALYST EXAM/ACTUAL EXAM
QUESTIONS & WELL DETAILED ANSWERS/GRADE A+
ASSURED
Chloride - (ANSWERS)- Major anion found in many natural waters !@#$%%%%%
- Can impart salty taste in H2O %%%%%%
What increases concentration of chloride in wastewater - (ANSWERS)Chloride in human diet
and softeners flushed into sanitary sewer system
2 most prevalent methods of measuring chloride - (ANSWERS)argentometric and mercuric
nitrate
Argentometric - (ANSWERS)Titration of sample with standard solution of silver nitrate (agno3)
- Indicator: Chromate ions (cro4)
- End point: reddish silver chromate
Mercuric Nitrate - (ANSWERS)Titration with standard mercuric nitrate solution
-ph must be adjusted between 2.3 and 2.8
- Indicator: Diphenyl carbazone
- End point: Change from blue to purple in presence of mercury
Interference of Mercuric Nitrate Method - (ANSWERS)Sulfide, bromide, orthophosphate (over
30 ppm), and iodide
Why does color change in water - (ANSWERS)Presence of decaying vegetable matter, metal
ions (ie. Iron) or industrial and domestic pollution
How is color measured - (ANSWERS)Measured using visual comparison method
Visual comparison method - (ANSWERS)Sample compared to standards using matched
nessler tubes
- Standards prepared with solution containing cholorplatinate and cobaltous chloride
Standard units for color - (ANSWERS)One unit= color resulting from 1 mg of platinum/L
2 color reporting - (ANSWERS)True and Apparent
True color - (ANSWERS)Color from dissolved substances, determine using sample treated to
remove turbidity
Apparent Color - (ANSWERS)Includes dissolved and suspended solids
Conductivity - (ANSWERS)H2Os capability to pass electrical flow
, CWEA GRADE I LABORATORY ANALYST EXAM/ACTUAL EXAM
QUESTIONS & WELL DETAILED ANSWERS/GRADE A+
ASSURED
!@#$%%%%%
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 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
QUESTIONS & WELL DETAILED ANSWERS/GRADE A+
ASSURED
Chloride - (ANSWERS)- Major anion found in many natural waters !@#$%%%%%
- Can impart salty taste in H2O %%%%%%
What increases concentration of chloride in wastewater - (ANSWERS)Chloride in human diet
and softeners flushed into sanitary sewer system
2 most prevalent methods of measuring chloride - (ANSWERS)argentometric and mercuric
nitrate
Argentometric - (ANSWERS)Titration of sample with standard solution of silver nitrate (agno3)
- Indicator: Chromate ions (cro4)
- End point: reddish silver chromate
Mercuric Nitrate - (ANSWERS)Titration with standard mercuric nitrate solution
-ph must be adjusted between 2.3 and 2.8
- Indicator: Diphenyl carbazone
- End point: Change from blue to purple in presence of mercury
Interference of Mercuric Nitrate Method - (ANSWERS)Sulfide, bromide, orthophosphate (over
30 ppm), and iodide
Why does color change in water - (ANSWERS)Presence of decaying vegetable matter, metal
ions (ie. Iron) or industrial and domestic pollution
How is color measured - (ANSWERS)Measured using visual comparison method
Visual comparison method - (ANSWERS)Sample compared to standards using matched
nessler tubes
- Standards prepared with solution containing cholorplatinate and cobaltous chloride
Standard units for color - (ANSWERS)One unit= color resulting from 1 mg of platinum/L
2 color reporting - (ANSWERS)True and Apparent
True color - (ANSWERS)Color from dissolved substances, determine using sample treated to
remove turbidity
Apparent Color - (ANSWERS)Includes dissolved and suspended solids
Conductivity - (ANSWERS)H2Os capability to pass electrical flow
, CWEA GRADE I LABORATORY ANALYST EXAM/ACTUAL EXAM
QUESTIONS & WELL DETAILED ANSWERS/GRADE A+
ASSURED
!@#$%%%%%
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 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
