AC-2021 Flashcards
Benzene and its derivatives undergo substitution reactions instead of addition reactions because
A. the integrity of the benzene ring and the stable pi-bonding pattern remains intact
B. the hydrogens of benzene are relatively loosely bound
C. the benzene ring is sterically crowded, hence only substitution can occur
D. the benzene ring is electron-rich
the integrity of the benzene ring and the stable pi-bonding pattern remains intact
Electrophiles are
a. electron-deficient species
b. electron-rich species
c. electrically neutral species
d. positively charged ions
electron-deficient species
SN2 means
a. two-step nucleophilic substitution mechanism involving both alkyl halide and nucleophile
b. one-step nucleophilic substitution mechanism involving both alkyl halide and nucleophile
c. two-step nucleophilic substitution mechanism involving only the alkyl halide
d. one-step nucleophilic substitution mechanism involving only the nucleophile
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 inexpensive and often the last resort?
A. Acid treatment using oxidation
B. Fusion technique
C. Dissolution using ultrasound & appropriate solvent
D. Simple dissolution
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
A. matrix
B. analyte
C. weight
D. dash
analyte
Glass containers are not suitable for
A. inorganic trace analyses
B. oil and grease determination
C. microbiological analyses
D. all of the above
inorganic trace analyses
Which of the following is a primary standard for use in standardizing bases?
A. Ammonium hydroxide
B. Sulfuric acid
C. Acetic acid
D. Potassium hydrogen phthalate
Potassium hydrogen phthalate
A solution has been prepared by transferring 60 mL from ortho-phosphoric acid 85% (v/v) and diluting it to 1.0 L. What is the concentration of the new solution?
A. 10.00%
B. 9.25%
C. 12.2%
D. 5.10%
5.1%
[Use Dilution Formula: C1V1 = C2V2]
A student has got three stock standard solutions of three different elements: zinc (Zn) 2000 ppm, cadmium (Cd) 1500 ppm, and lead (Pb) 1000 ppm. A student took 10 mL from each solution and transferred it to a 200 mL volumetric flask, then completed the total volume with solvent. What is the final concentration of each element in the diluted mixed solution?
A. 50 ppm Zn, 32 ppm Cd, 25 ppm Pb
B. 100 ppm Zn, 75 ppm Cd, 50 ppm Pb
C. 75 ppm Zn, 75 ppm Cd, 50 ppm Pb
D. 100 ppm Zn, 25 ppm Cd, 25 ppm Pb
100 ppm Zn, 75 ppm Cd, 50 ppm Pb
[Use Dilution Formula: C1V1 = C2V2]
The HPLC column type in which molecules are separated according to size is:
A. Ion exchange
B. Size exclusion
C. Normal phase
D. Reverse phase
Size exclusion
During ignition for ashing, muffle furnaces that go up to 1100°C are used primarily for this, and ___ is needed to contain the sample.
A. Porcelain crucible
B. Evaporating dish
C. Beaker
D. All of the above
Porcelain crucible
A graphical representation of measuring signal as a function of the quantity of analyte is called:
A. Calibration curve
B. Quality Control Chart
C. Absorbance Chart
D. None of the above
Calibration curve
In AAS method, if the sample concentration is too high to permit accurate analysis in the linearity response range, there are alternatives that may help bring the absorbance into the optimum working range.
A. Sample dilution
B. Using an alternative wavelength having a lower absorptivity
C. Reducing the path length by rotating the burner head
D. All of the above
All of the above
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:
A. Take the average of multiple measurements using the graduated cylinder
B. Measure the liquid using a 25 mL graduated cylinder instead
C. Estimate the measurement obtained from the graduated cylinder to an additional significant figure
D. Measure the liquid using a 10 mL graduated pipette instead
Measure the liquid using a 10 mL graduated pipette instead
A buffer solution may be a mixture of:
A. A weak acid and its salt
B. A weak base and its salt
C. An excess of a weak acid with a strong base
D. All of the above
All of the above
Which statement is true?
A. The value of the equilibrium constant increases with the addition of a catalyst
B. A catalyst speeds up both the forward and reverse reaction rates
C. The greater the activation energy, the faster the rate of reaction
D. A catalyst increases the rate of reaction by decreasing the number of collisions
A catalyst speeds up both the forward and reverse reaction rates
What volume is occupied by 4.00 g of carbon dioxide, CO? (44.0 g/mol) gas at a pressure of 0.976 atm and a temperature of 25.00 °C?
A. 0.191 L
B. 19.1 L
C. 2.28 L
D. 22.8 L
2.28 L
Molecular oxygen is highly soluble in the blood because:
A. The hemoglobin molecule can bind up to four oxygen molecules
B. The solubility of oxygen is increased by the higher temperature of the body
C. Pressure is increased inside the body
D. Pressure inside the body is different outside of it
The hemoglobin molecule can bind up to four oxygen molecules
When water is heated in a beaker, bubbles of air form on the side of the glass before the water boils. This shows that:
A. The solubility of gases in water decreases with increasing temperature
B. The solubility of gases in water increases with increasing temperature
C. The solubility of gases in water decreases with decreasing temperature
D. The solubility of gases in water increases with decreasing temperature
The solubility of gases in water decreases with increasing temperature
Method of passing the sample through a metal or plastic mesh of a uniform cross-sectional area to separate particles into uniform sizes:
A. Pulverizing
B. Macerating
C. Milling
D. Sieving
Sieving
In handling acid wastes, what type of protective gloves should be used?
A. Cloth gloves
B. Surgical gloves
C. Rubber gloves
D. Disposable plastic gloves
Rubber gloves
What type of container must be used for acid or alkali wastes?
A. Polyethylene drum
B. Metal drums
C. Fiber drums
D. Cloth container
Polyethylene drum
A solid waste management practice which refers to the controlled decomposition of organic matter by microorganisms mainly bacteria and fungi into human-like product
A. Composting
B. Recycling
C. Bioremediation
D. Reducing
Composting
A series of reference standard solutions that have known and accurate pH values at different temperatures used for pH meter calibration is called:
A. Buffer Solutions
B. QC Solutions
C. pH Solutions
D. None of the above
Buffer Solutions
The law that states the linear relationship between absorbance and concentration of an absorbing species is:
A. Beer-Lambert’s Law
B. Charles Law
C. Boyle’s Law
D. Avogadro’s Law
Beer-Lambert’s Law
Type of quality-control sample used to evaluate the effects of sample matrices on the performance of an analytical method:
A. Matrix Duplicate
B. Matrix Spike
C. Method Blank
D. Reagent Blank
Matrix Spike
Component of error which, in the course of a number of analyses of the same measurand, remains constant or varies in a predictable way:
A. Random Error
B. Analyst’s Error
C. Systematic Error
D. Uncertain Error
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
What is the volume?
A. 50.45 mL
B. 50.27 mL
C. 50.37 mL
D. 50.17 mL
50.27 mL
50.1227/0.99707
It is a pure dry solid substance of known chemical composition used in the direct standardization of a solution:
A. Primary standard
B. Secondary standard
C. Analytical standard
D. Indicator
Primary standard
Closeness of the agreement between the results of a measured value and a true value is referred to as:
A. Accuracy
B. Precision
C. Mean
D. Error
Accuracy
Sample preparation technique used prior to instrumental analysis of metals:
A. Acid digestion
B. Liquid-liquid extraction
C. Sieving
D. Clean-up
Acid digestion
Which of the following chemicals may be used to neutralize waste containing sodium hydroxide?
A. Potassium Hydride
B. Ammonia
C. Hydrochloric Acid
D. Buffer Solution
Hydrochloric Acid
Which of the following are possible routes of exposure to hazardous substances?
A. Inhalation
B. Dermal
C. Ingestion
D. All of the above
All of the above
According to Revised DAO 04-36, the appropriate waste label shall include:
A. Volume of Waste
B. Generator ID Number
C. Container Material
D. All of the above
All of the above
Sampling type that eliminates questions of bias in selection:
A. Composite
B. Stratified
C. Systematic
D. Random
Random
(eliminate bias by giving equal chance of selection)
Reliability of the results decreases with a decrease in the level or concentration of:
A. Matrix
B. Analyte
C. Reactant
D. Product
Analyte
Properties of nitric acid making it the preferred acid for digesting samples for metals:
A. Acts as a strong acid
B. Acts as an oxidizing agent
C. Does not form insoluble compounds with metals/nonmetals
D. All of the above
All of the above
Possible sources of contamination during sample preparation include:
A. Reagents (tracers)
B. Glassware/equipment
C. Cross-contamination between high- and low-activity samples
D. All of the above
All of the above
The size of the sample taken for analysis depends on the concentration of the:
A. analyte
B. The equipment to be used
C. specific tests
D. All of the above
All of the above
Locating the adulterated portion of the lot for sampling is an example of:
A. Random sampling
B. Selective sampling
C. Composite sampling
D. Stratified sampling
selective sampling
“adulterated”
Quantitative chemical analysis of a weighing sample, usually of a separated and dried precipitate, is called:
A. Titrimetric analysis
B. Volumetric analysis
C. Gravimetric analysis
D. Elemental analysis
Gravimetric analysis
The substance which does the dissolving and must be greater than 50% of the solution is called:
A. Solvent
B. Solute
C. Mixture
D. Solution
Solvent
Requirements of a primary standard include:
A. High purity, 99.9% or better
B. Solubility in air
C. Absence of hydrate water
D. All of the above
All of the above
Requirements of a primary standard include:
A. High purity, 99.9% or better
B. Stability in air
C. Absence of hydrate water
D. All of the above
All of the above
Used for vacuum filtration using filter paper:
A. Porcelain crucible
B. Buchner funnel
C. Rotary evaporator
D. Rubber aspirator
Buchner funnel
In chromatography, the technique carried out on glass plates or strips of plastic or metal coated on one side with a thin layer of adsorbent is:
A. HPLC
B. GC
C. Paper Chromatography
D. Thin Layer Chromatography
Thin Layer Chromatography
Chromatography is used to:
A. Separate two or more compounds based on their polarities
B. Separate two or more compounds based on their masses
C. Separate two or more compounds based on how strongly they interact with other compounds
D. All of the above
All of the above
A technique for separating mixtures into their components in order to identify and/or quantify the constituents is:
A. Spectroscopy
B. Chromatography
C. Gravimetry
D. Titrimetry
Chromatography
A graph showing the detector’s response as a function of elution time, including the band’s shapes, position, and resolution, is called:
A. Monitor display
B. Quality control chart
C. Calibration curve
D. Chromatogram
Chromatogram
Under the Bronsted concept of acids and bases, a base is:
A. A proton donor
B. A proton acceptor
C. A hydroxide donor
D. An electron pair donor
A proton acceptor
Which of the following is NOT an acid-base conjugate pair?
A. HCN and CN-
B. H2O and OH-
C. H2S and OH-
D. NH3 and NH4
H2S and OH-
Predict the products of the following acid-base reaction: NH3 + HNO3 ?
A. NH2OH + HNO2
B. NH4NO3
C. NH4OH
D. no reaction takes place
NH4NO3
Which of the following is not a common method used for purification?
A. Sublimation
B. Crystallization
C. Electrolysis
D. Chromatography
Electrolysis
( primarily used for the decomposition of compounds)
The solution of an impure compound and solvent is concentrated to get:
A. Unsaturated solution
B. Undersaturated solution
C. Saturated solution
D. Oversaturated solution
Saturated solution
Insoluble impurities from a solution during crystallization are removed by:
A. Drying
B. Filtration
C. Heating
D. Cooling
Filtration
Crystal phases can be interconverted by varying:
A. Temperature
B. Pressure
C. Size
D. Viscosity
Temperature
Which of the following is not separated through the distillation process?
A. Acetone and water
B. Aniline and chloroform
C. Impurities in seawater
D. Milk and water
Milk and water
[milk is an emulsion, which distillation cannot separate]
Column chromatography is based on the principle of:
A. Exclusion principle
B. Differential adsorption
C. Absorption
D. Ion-exchange
Differential adsorption
[column - AD sorption]
Select the correct statement from the following options:
A. The lesser the polarity of the solute, the more strongly it will be adsorbed on a polar surface.
B. The greater the polarity of the solute, the more weakly it will be adsorbed on a polar surface.
C. The greater the polarity of the solute, the more strongly it will be adsorbed on a polar surface.
D. All of the mentioned options.
The greater the polarity of the solute, the more strongly it will be adsorbed on a polar surface.
The elution power of a solvent is determined by:
A. Overall polarity
B. The polarity of the stationary phase
C. The nature of the sample components
D. All of the mentioned options.
All of the mentioned options.
The principle on which thin layer chromatography is based is that:
A. Different compounds are absorbed on an absorbent to different degrees.
B. Different compounds are absorbed on an absorbent to the same degrees.
C. Different compounds are adsorbed on an adsorbent to different degrees.
D. Different compounds are adsorbed on an adsorbent to the same degrees.
Different compounds are adsorbed on an adsorbent to different degrees.
[ADsorbent - DIFF]
Which type of chromatography is used for structural analysis?
A. Column chromatography
B. Paper chromatography
C. Partition chromatography
D. Affinity chromatography
Paper chromatography
Affinity chromatography is used for the analysis and isolation of:
A. Insoluble starch substances
B. Enzyme tyrosinase
C. Antibodies bound with a covalently attached antigen on a cellulose column
D. All of the mentioned
All of the mentioned
Which of the following is not an application of high-performance liquid chromatography?
A. Analysis of proteins, drugs, and explosives
B. Separation of pharmaceutical drugs
C. Elimination of undesirable substances from blood
D. Separation of lipids, fatty acids, and steroids
Elimination of undesirable substances from blood
[HPLC is mainly used for analysis and separation]
Which of the following is an application of ion exchange chromatography?
A. The softening of hard water
B. The demineralization of water
C. The separation and determination of anions
D. All of the mentioned
All of the mentioned
The quantitative analysis is done using:
A. Ion exchange chromatography
B. Thin layer chromatography
C. Gas chromatography
D. Liquid chromatography
Gas chromatography
The temperature at which solid and liquid coexist in equilibrium is called:
A. Melting point of liquid
B. Freezing point of liquid
C. Freezing point of solid
D. All of the mentioned
Freezing point of liquid
The analysis of electromagnetic radiation scattered, absorbed, or emitted by the:
A. Radiology
B. Astronomy
C. Spectroscopy
D. Anatomy
Spectroscopy
The different types of energies associated with a molecule are:
A. Electronic energy
B. Vibrational energy
C. Rotational energy
D. All of the mentioned
All of the mentioned
Select the correct statement from the following options:
A. Spectroscopic methods require less time and more amount of sample than classical methods.
B. Spectroscopic methods require more time and more amount of sample than classical methods.
C. Spectroscopic methods require less time and less amount of sample than classical methods.
D. Spectroscopic methods require more time and less amount of sample than classical methods.
Spectroscopic methods require less time and less amount of sample than classical methods.
[less - less]
Which of the following is not in the infrared spectrum?
A. HCl
B. H2O
C. CO2
D. CH4
CH4
The components of the mixture in column chromatography are eluted in order of:
A. Increasing polarity and increasing distribution ratio.
B. Increasing polarity and decreasing distribution ratio.
C. Decreasing polarity and increasing distribution ratio.
D. Decreasing polarity and decreasing distribution ratio.
Increasing polarity and increasing distribution ratio.
Which equipment must be used in the detection of Pb2+ in blood?
A. AAS
B. IR Spectrometer
C. NMR Spectrometer
D. Mass Spectrometer
AAS
(for quantifying metal ions)
An industrial source of alcohol is:
A. Coal
B. Corn
C. Sugar
D. Ether
Sugar
What is the most common isotope of hydrogen?
A. H has only one isotope.
B. Protium
C. Deuterium
D. Tritium
Protium
A 22/24 stopper is used in a volumetric flask. Which of the following is true?
A. The diameter is 24 cm and the height is 22 cm.
B. The diameter is 22 cm and the height is 24 cm.
C. The diameter is 24 mm and the height is 22 mm.
D. The diameter is 22 mm and the height is 24 mm.
The diameter is 22 mm and the height is 24 mm.
[diameter (mm)/height (mm)
This type of glass is commonly used for laboratory glassware:
A. Amber
B. Quartz
C. Fused silica
D. Borosilicate
Borosilicate
In the analysis of a mixture by gas chromatography, which of the following gives the best clues to whether the components can be analyzed with any degree of accuracy?
A. Column length
B. Retention times
C. Column temperature
D. Flow rate of the carrier gas
Retention times
The determination of the equilibrium constant of a colored species can be done via which technique?
A. Conductance
B. Ion-exchange
C. Electrophoresis
D. Spectrophotometry
Spectrophotometry