Which piece of lab glassware listed below is the most accurate for measuring an amount of sample?
Volumetric pipet
Specific conductance or conductivity is depends on what factors?
TDS and temperature
What is caused by the presence of suspended matter such as silt, finely divided organic and inorganic matter and microscopic plants such as algae?
Turbidity
What is the range of the pH scale?
0-14
The pH of a sample is preserved with an acid to pH 2.0. If the sample pH initially was 7.0, how many times more acidic is the sample at 2.0?
100,000 times
What is a problem with hard water?
The water forms insoluble precipitates of soap
Why must the operator be cautious about using a home as a sampling
location?
The home may have a water softener
A pH reading of 7.0 indicates what?
The water is neither acidic or basic
What are two types of color found in water?
True color and apparent color
The greatest errors in laboratory tests are usually caused by what?
Improper sampling
The pH of water being softened has risen from 7.0 to 9.0. How many times more basic is the pH?
100 times more basic
The operator has collected a sample for pH at a remote tap. The pH meter was calibrated with a 7.0 and a 10.0 pH buffer, but the pH of the sample reads 6.5. What should the operator do?
Recalibrate the meter with pH buffers that bracket the result, collect a fresh sample and re-measure the pH
What sample volume is used for collection of all coliform samples?
100 mL
Accurate water temperature readings are important not only for historical purposes but also because of its influence on what?
Chemical reaction rates and water stability
What is a test to determine the degree of calcium carbonate saturation in a water sample?
Marble test
The maximum allowable concentration of this metallic salt is 250 mg/L and is established more for taste reasons than as a health hazard.
Chloride
Why is sodium thiosulfate added to a Bac-T sample?
To neutralize any residual chlorine
What treatment methods can remove or reduce true color?
•Slow sand filtration, manganous greensand filtration or diatomaceous earth filtration
•Coagulation with ferric chloride, aeration or sedimentation
•Coagulation, chlorination or ozonation
•Coagulation and flocculation
Information from algae counts can serve what purpose?
Help explain the cause of color, turbidity, taste and odors
What are the two types, or classifications, of water hardness?
Cabonate and non-carbonate
High amounts of nitrate in drinking water can cause what?
Blue baby syndrome (methemoglobinemia)
A Class D type fire has ignited in the lab. This fire involves what?
Combustible metals
Convert 550 C to F
1,022 degrees F
What are jar tests designed to show?
The effectiveness of chemical treatment in a water treatment facility
What is the maximum holding time for a total coliform sample?
•28 days
•30 hours
•15 minutes
•6 hours