Lab Analysis Flashcards
Turbidity analyses on samples should be measured?
As soon as possible.
Which sample quantity should be collected for a
hardness analysis?
100 mL
Which is the minimum size turbidity sample that
should be collected?
100 mL
Which sample should not be collected in a glass container?
Fluoride
Bacteriological sample storage refrigerator temperatures
should range from ____________.
10 to 50 c
How long can a preserved sample that is to be analyzed
for manganese content be stored?
6 months
Samples to be analyzed for manganese are preserved with?
Nitric Acid
In the total coliform colisure test, if coliforms are present,
the special medium will turn?
Red to purple
What is the chemical formula for ammonia?
NH3
Electrically charged atoms such as Na+ and Cl-
are called?
Ions
How often should a softening treatment plant analyze
for hardness?
Daily
Which test would be used to determine
total alkalinity?
Methyl Orange test
Which method is used to calculate the calcium carbonate
stability of water?
Langelier Index
Who is responsible for sample preservation?
The sampler
If hardness samples need to be stored, which preservative
should be used?
Nitric acid
How long can samples be held for fluoride analysis?
7 days
Which water quality parameter can be properly determined
by collecting a composite sample?
Zinc
Water that is to be analyze for inorganic metals should be
acidified to a pH that is _______.
< 2.0 pH units
Nematodes are?
Roundworms
An actinomycetes bacterial colony on an agar plate
would have a ________.
Dull powdery appearance with fuzzy border.
Which level of Threshold Odor Number (TON) will
result in customer complaints?
5 (TON)
Suspended solids that are referred to as settleable solids
will settle unaided to the bottom of a sedimentation
basin within?
4 hours
What would be considered very hard water measure in
mg/L as CaCO3 for the Sawyer, Briggs, or
Ficke classification?
> 300 mg/L
Water that is too soft will cause?
Soap scum
Why is it important to measure
Total Organic Carbon
(TOC)
TOC correlates with production of disinfection
by-products?
Which element is found in all acids?
Hydrogen
When a base reacts with an oxide of a nonmetal
it will produce _______.
A salt
When anhydrides react with water they produce?
Acids and hydroxides
Oxides of nonmetals in water will _______.
cause acidity.
What is the formula for the
Langelier Index?
Ll = pH - pHs
Giardia lamblia species are?
Protozoans
The specific gravity of water is based on using
a temperature of _______.
40 c
Jar testing procedures are applicable to ________.
conventional treatment.
The incubation time for the membrane filter method is?
24 hours
Which type of glassware is used in dispensing solutions
during titrations?
Burette
Samples confirmed in the presence-absence test
must also be tested for?
Escherichia Coli
(e-coli)
Which should the heterotrophic plate count value be in
water that has been properly treated?
< 500 colonies per mL
Why should a Jar test procedure be done as quickly
as possible after collecting the raw water sample?
Changes in temperature will
significantly affect results.
Which is the preferred method of hardness analysis?
Titration with
ethylenediaminetetraacetic
acid
Which method is used for Fluoride analysis?
SPADNS
When EDTA is added to a sample being tested for
hardness, the end point causes the dye in the
sample to change to _______.
blue
Which type of pipette has a single ring near the top?
Transfer pipette
Titration for alkalinity analyses uses which instrument to determine the end point?
pH meter
The number of grains per gallon (gpg) can be converted
to mg/L hardness by _______.
multiplying by 17.12
Hardness samples that have been acidified can be
stored for _______.
28 days
Which type of bottle should be used and how should it be
cleaned for taste-and-odor samples?
Glass bottles, cleaned with detergent and rinsed with
distilled water.
After a sample to be analyzed for manganese has
been acidified, its pH must be?
< 2 pH units
Conductivity (as it pertains to water)
is __________.
the measure of a solution’s ionic strength and an indirect
measure of the total dissolved solids.
When should a water treatment plant take action on odors
in finished water?
At 3-TON
Dissolved metals in a water sample are considered to
be metals that are?
Unacidified and pass through
0.45 µm membrane.
Salmonella species are?
Bacteria
“Standared Methods” defines QA as?
Producing data that is precise and unbiased.
Atoms that have the same atomic number, but a different
mass number are called?
Isotopes
The oxidation number of an element is also called
Its _________ number.
Valence
When oxidation occurs?
Electrons are lost by the species being oxidize.
When reduction occurs?
Electrons are gained by the species being reduced.
A double replacement reaction is the same as?
An ionic reaction.
What is the strongest oxidizing agent?
Cl2 + 2e-
Which will show Brownian motion?
Colloids
Molarity is the number of?
Moles of solute per liter of solution.
What would increase in solubility as the
temperature decreases?
Chlorine gas
Crystalline compounds that contain water are called?
Hydrates
What is it called when water molecules associate
with ions?
Hydration of ions
If a hydrocarbon has one or more of its hydrogen atoms
replaced with a hydroxyl (OH) group it is called?
An alcohol
When is water considered to be in equilibrium?
pH - pHs = O
How are total calcium analyses reported?
In mg/L as CaCO3
Which is the most probable solution if “midges” can be
seen in the finished water?
Increase chlorination and backwash.
Typically, which constituent would account for the least
amount of Total Dissolved Solids (TDS)?
Dissolved organic matter
Which algal genera in the chlorophyta phylum are
filamentous and can form tangled mats in ponds?
Rhizoclonium
If phenolphthalein alkalinity equals total alkalinity, which
species is present?
OH-
If phenolphthalein alkalinity is zero, which species
is present?
HCO-3
In general, for every 10 electrical conductivity units there
are approximately how many mg/L of dissolved solids?
6 to 7 mg/L
Ionic compounds are formed when _______.
a transfer of electrons occurs.
The measure of attraction that atoms have for each other
when they share electrons is called?
Electronegativity
Which genera of cyanobacteria release a variety of
odorous organic sulfur compounds, especially
after dying?
Microcystis
If two combining atoms have an electronegativity difference
that is more than 1.6, then ________.
ionic bonding will occur.
Which sulfer bacteria are photosynthetic?
Chromatium
Which is the quantitative relationship of chemical reactants
and their products known as?
Stoichiometry
If a water molecule has both of its hydrogen atoms
replaced by alkyl groups, it is called?
An ester
In general, an electrical conductivity change of 10 units
represents approximately _________ of dissolved solids?
6.0 to 7.0 m/L
Which is the first level of “TDS” that is considered unfit
for human consumption?
4,000 mg/L
Which sulfur bacteria are photosynthetic?
Chlorobium
Which chemical is use in desiccators to remove moisture
from the air in the desiccator?
Calcium sulfate
Which laboratory incubator is most useful for total coliform
and HPC (Heterotrophic Plate Count) analyses?
Dry-Heat incubator
Under no circumstances should a composite sample be collected for which type of analysis?
a. Bacteriological
b. Total dissolved solids
c. Alkalinity
d. Turbidity
a. Bacteriological
The number of monthly distribution system chlorine residual samples required is ________.
a. based on water withdrawal permit limit.
b. based on system size.
c. based on population.
d. different for each state.
c. based on pupulation.
Which is (are) the ideal indicator for pathogens?
a. Salmonella species
b. Coliform group bacteria
c. Gram-negative cocci
d. Gram-negative coccobacilli
b. Coliform group bacteria
When one substance is dissolved in another and will not settle out, which is the product called?
a. An emulsion
b. A compound
c. A suspension
d. A solution
d. A solution
Acids, bases, and salts lacking carbon are ________.
a. ketones.
b. aldehydes.
c. organic compounds.
d. inorganic compounds.
d. inorganic compounds.
Which type of sample should always be collected for determining the presence of coliform bacteria?
a. Time composite.
b. Grab sample.
c. Proportional.
d. Composite.
b. Grab sample.
Samples to be tested for coliforms can be refrigerated for up to ______ hours before analysis, but should be done as soon as possible.
a. 4
b. 6
c. 8
d. 12
c. 8
When a water sample is acidified, the final pH of the water must be _______.
a. < 2.0
b. < 2.5
c. < 3.0
d. < 3.5
a. < 2.0
Which chemical is used to remove residual chlorine from water?
a. Na2S2O3
b. Na2SiO3
c. Na2SiF6
d. NaOCl
a. Na2S2O3
When a sample is collected, which causes its quality to begin to change?
a. CO2
b. Dissolved gases
c. Biological activity
d. pH
c. Biological activity
Water that is to be analyzed for inorganic metals should be acidified with _________.
a. dilute hydrochloric acid.
b. concentrated hydrochloric acid.
c. dilute nitric acid.
d. concentrated nitric acid.
d. concentrated nitric acid.
A solution used to determine the concentration of another solution is called a ________.
a. saturated solution.
b. standardized solution.
c. concentrated solution.
d. dilute solution.
b. standardized solution.
Which method would you use to concentrate and retrieve low numbers of bacteria from a large quantity of water?
a. Colilert
b. Colisure
c. Membrane filtration
d. MPN (Most Probable Number)
c. Membrane filtration
A typical coliform colony in the membrane filter method has the following characteristics:
a. Blue with lustrous surface sheen
b. Pink to dark red with green metallic surface sheen
c. Pink or yellow with lustrous to metallic surface sheen depending on species
d. Yellow with silver metallic to lustrous surface sheen
b. Pink to dark red with green metallic surface sheen
In the presumptive phase of the Most Probable Number test, how long does it take for the coliforms to produce gas?
a. 12 to 24 hours
b. 24 to 48 hours
c. 24 to 36 hours
d. 36 to 48 hours
b. 24 to 48 hours
Chemical analysis for synthetic organic compounds should not be collected in containers made of _________.
a. polytetrafluoroethylene.
b. stainless steel.
c. polypropylene.
d. borosilicate.
c. polypropylene.
How much acid per 100 mL should be used to preserve a sample for later hardness analyses?
a. 0.1 mL
b. 0.2 mL
c. 0.5 mL
d. 1.0 mL
c. 0.5 mL
Conductivity measurements can assist the laboratory analyst in __________.
a. measuring the electrical strength, which is directly proportional to the number of free electrons.
b. estimating the concentration of calcium carbonate.
c. evaluating variations in the concentration of suspended particles.
d. determining the degree of mineralization of the water.
d. determining the degree of mineralization of the water.
Water that is to be analyzed for inorganic metals should be filtered for _______ before ________.
a. dissolved metals; analyses
b. suspended metals; analyses
c. dissolved metals; preserving
d. suspended metals; preserving
c. dissolved metals; preserving
In routine water quality sampling, which one of the following is an early warning sign that conditions are becoming more conducive to sulfate-reducing bacteria?
a. Increase in ferrous iron
b. Increase in ferric iron
c. Dramatic decline in dissolved oxygen
d. Increase in sulfides
c. Dramatic decline in dissolved oxygen
