Past Board 2021 Flashcards
Benzene and its derivatives undergo substitution reactions instead of addition reactions because
the integrity of the benzene ring and the stable pi-bonding pattern remains intact
Electrophiles are
electron deficient species
Nucleophiles
electron rich species
SN2 means
one step nucleophilic substitution mechanism involving both alkyl halide and nucleophile
In the decomposition and dissolution of solids during sample preparation, which of the following
is expensive and often the last resort?
Fusion technique
It is important to discard containers that are scratched or abraded on their interior surfaces. The
internal surface area of a container, whether used for sample preparation or storage, may cause
loss of
analyte
Glass container is not suitable for
inorganic trace analyses
Which of the following is a primary standard for use in standardizing bases?
Potassium hydrogen phthalate
A student has got three stock standard solutions of 3 different elements, zinc (Zn) 2000 ppm,
cadmium (Cd) 1500 ppm and lead (Pb) 1000 ppm. A student took 10 mL from each solution and
transfers it to 200 mL volumetric flask then completed to total volume with solvent. What is the
final concentration of each element in the diluted mix solution?
100 ppm Zinc, 75 ppm Cd, 50 ppm Pb
A solution has been prepared by transferring 60 mL from Ortho-phosphoric acid 85 % (v/v)
H3PO4 and diluting it to 1.0 L, what is the concentration of the new solution.
5.10%
The HPLC column type in which molecules are separated according to size.
size exclusion
During ignition for ashing, muffle furnaces that go up to 1100oC are used primarily for this and
________ is needed to contain the sample.
porcelain crucible
A graphical representation of measuring signal as a function of quantity of analyte.
Calibration curve
In AAS method, If the sample concentration is too high to permit accurate analysis in linearity
response range, there are alternatives that may help bring the absorbance into the optimum
working range.
All of the above (sample dilution, using an alternative wavelength having a lower absorptivity, reducing the path length by rotating the burner hand)
A student has to measure out 9.40 mL of a liquid and selects a 100 mL graduated cylinder. To
improve the accuracy of the measurement, it would be most effective to:
measure the liquid using a 10 mL graduated pipette instead
A buffer solution may be a mixture of
all of the above (weak acid and its salt, a weak base and its salt, an excess of a weak acid with a strong base)
What volume is occupied by 4.00 g of carbon dioxide, CO2 (44.0) gas at a pressure of 0.976 atm
and a temperature of 25.00C?
2.28 L
Which statement is true?
A catalyst speeds up both the forward and reverse reaction rates
Law that states the linear relationship between absorbance and concentration of an absorbing
species
Beer-Lambert’s Law
Molecular oxygen is highly soluble in the blood because
the hemoglobin molecule can bind up to four oxygen molecules
A series of reference standards solutions that have known and accurate pH values at different
temperatures used for pH meter calibration.
Buffer Solutions
Type of quality-control sample used to evaluate the effects of sample matrices on the
performance of an analytical method
Matrix Spike
What type of container must be used for acid or alkali wastes?
Polyethylene Drums
When water is heated in a beaker, bubbles of air form on the side of the glass before the water
boils. This shows that
the solubility of gases in water decreases with increasing temperature
The absorbance of different concentrations of potassium permanganate determined through UV-
Vis Spectrophotometer is shown below.
Concentration, ppm Average Absorbance
1.11 0.015
22.2 0.236
44.4 0.512
66.6 0.751
88.8 1.062
The Quality Control Sample for this run gave an average absorbance reading of 0.486. The
theoretical concentration of the QC sample is 44.4 ppm. Calculate for the error of this QC run.
0.0524
Method of passing the sample through a metal or plastic mesh of a uniform cross-sectional area to
separate particles into uniform sizes.
sieving
A solid waste management practice which refers to the controlled decomposition of organic
matter by microorganisms, mainly bacteria and fungi, into a humus-like product.
Composting
In handling acid wastes, what type of protective gloves should be used?
Rubber gloves
Component of error which, in the course of a number of analyses of the same measurand, remains
constant or varies in a predictable way.
Systematic Error
Determine the actual volume contained in a 50.0 mL volumetric flask given the following data:
Mass of water: 50.1227 g Density of water at 25 ̊ C : 0.99707 g/mL
50.27 mL
It is a pure dry solid substance of known chemical composition used in the direct standardization
of solution.
primary standard
Which of the following chemicals may be used to neutralize waste containing caustic soda?
Hydrochloric Acid
Sample preparation technique used prior to instrumental analysis of metals.
acid digestion
It is the closeness of the agreement between the result of a measured value and a true value.
Accuracy
Which of the following are possible routes of exposure of the hazardous effect of waste?
all of the above (Inhalation, Dermal, Ingestion)
According to Revised DAO 04-36, the appropriate waste labels shall include:
All of the above (Volume of Waste, Generator ID Number, Container Material)
Sampling type that eliminates questions of bias in selection
random
Reliability of the results decreases with a decrease in the level or concentration of the:
analyte
Properties of nitric acid making it the preferred acid for digesting samples for the analysis of
metals.
All of the above (acts as a strong acid, as an oxidizing agent, does not form insoluble compounds with metals/nonmetals)
Possible sources of contamination during sample preparation include:
All of the above (Reagents (tracers), Glassware/equipment, Cross-contamination between high- and low-activity samples)
Locating the adulterated portion of the lot for sampling is an example of
selective sampling
The size of the sample taken for analysis depends on the concentration of the
All of the above (analyte, equipment to be used, specific tests)
Requirements of a primary standard.
All of the above (High Purity, 99.9% or better, Stability in air, Absence of hydrate water)
Used for vacuum filtration using filter paper.
Buchner funnel