Cwea Grade 1 Lab Analyst Practice Test Part 2 Questions With Answers & Detailed Rationales

CWEA grade 1 lab analyst practice test part 2 fc fc fc fc fc fc fc fc




1. What is chloride?: Major anion found in many natural waters - Can impart salty taste in H2O
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2. What increases the concentration of chloride in wastewater?: Chloride in human
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diet and softeners flushed into sanitary sewer system
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3. 2 most prevalent methods of measuring chloride?: argentometric and mercuric nitrate
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4. What is the Argentometric method?: Titration of the sample with a standard solution of silver
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nitrate (AgNO3) - Indicator: Chromate ions (CrO4) - End point: reddish silver chromate
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5. What is the Mercuric Nitrate method?: Titration with standard mercuric nitrate solution -
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pH must be adjusted between 2.3 and 2.8 - Indicator: Diphenyl carbazone -
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End point: Change from blue to purple in the presence of mercury
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6. Which of the following can be an Interference of the Mercuric Nitrate Met
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hod?: Sulfide, bromide, orthophosphate (over 30 ppm), and iodide
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7. Why does the color change in water? fc fc fc fc fc fc




a. Presence of decaying vegetable matter fc fc fc fc




b. metal ions (ie. iron) fc fc fc




c. industrial and domestic pollution fc fc fc




d. All of the above: d fc fc fc fc




8. How is color measured: Measured using visual comparison method
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9. What is the visual comparison method: Sample compared to standards using matching nessler
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tubes - Standards prepared with solution containing chloroplatinate and cobaltous chlorid
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10. What is the standard unit for color?: One unit= color resulting from 1 mg of platinum/L
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11. What is 2-color reporting?: True and Apparent fc fc fc fc fc fc




12. Define True color: Color from suspended solids, determine using sample treated to remove turbidity
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13. What is Apparent Color?: Color from both dissolved and suspended solids
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14. What is Conductivity?: H2O capability to pass electrical flow
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15. What is the conductivity of pure water?: 0 fc fc fc fc fc fc fc




16. What are the Units of conductivity?: µS/cm (micromhos/cm)
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17. What Temperature should conductivity be read at?: 25 degrees Celcius
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18. How is conductivity affected?: Mobility of ions, conductivity is dependent on viscosity
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19. What is Viscosity?: the resistance of a liquid to flow
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20. Describe the relationship of temperature and viscosity?: Inverse fc fc fc fc fc fc fc




21. What is an Acid?: A compound that liberates hydrogen ions and has a pH below 7.
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22. What is Alkalinity?: The measurement of a sample's capacity to neutralize acid.
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