OCT 2021 PBE Flashcards by ellie s

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

a. the integrity of the benzene ring and the stable pi-bonding pattern remains intact

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Electrophiles are
a. electron deficient species
b. electron rich species
c. electrically neutral species
d. positively charged ion

electron deficient species

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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

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In the decomposition and dissolution of solids during sample preparation, which of the following
is expensive and often the last resort?
a. Acid treatment using oxidation
b. Fusion technique
c. dissolution using ultrasound & appropriate solvent
d. Simple dissolution

Fusion technique

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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. ash

analyte

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Glass container is not suitable for
a. inorganic trace analyses
b. oil and grease determination
c. microbiological analyses
d. all of the above

inorganic trace analyses

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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

d. Potassium hydrogen phthalate

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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.
a. 10.10%
b. 9.25%
c. 12.2%
d. 5.10%

5.10%

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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?
a. 50 ppm Zinc, 32 ppm Cd, 25 ppm Pb
b. 100 ppm Zinc, 75 ppm Cd, 50 ppm Pb
c. 75 ppm Zinc, 75 ppm Cd, 50 ppm Pb
d. 100 ppm Zinc, 25 ppm Cd, 25 ppm Pb

b. 100 ppm Zinc, 75 ppm Cd, 50 ppm Pb

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The HPLC column type in which molecules are separated according to size.
a. Ion exchange
b. size exclusion
c. normal phase
d. reverse phase

size exclusion

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During ignition for ashing, muffle furnaces that go up to 1100oC 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

a. porcelain crucible

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A graphical representation of measuring signal as a function of quantity of analyte.
a. Calibration curve
b. Quality Control Chart
c. Absorbance Chart
d. None of the above

Calibration curve

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n 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.
a. sample dilution
b. using an alternative wavelength having a lower absorptivity
c. reducing the path length by rotating the burner hand
d. All of the above

All of the above

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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.

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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

d. all of the above

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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

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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?
a. 0.191 L
b. 19.1 L
c. 2.28 L
d. 22.8 L

2.28 L

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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

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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

a. the solubility of gases in water decreases with increasing temperature

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The absorbance of different concentrations of potassium permanganate determined through UV
Vis Spectrophotometer is shown below.

Concentration, ppm Avg 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.
a. 0.0524
b. 0.0552
c. 0.0465
d. 0.00052

0.0524

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Method of passing the sample through a metal or plastic mesh of a uniform cross-sectional area to
separate particles into uniform sizes.
a. sieving
b. pulverizing
c. macerating
d. milling

sieving

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In handling acid wastes, what type of protective gloves should be used?
a. Cloth gloves
b. Surgical gloves
c. Rubber gloves
d. Disposal plastic gloves

Rubber gloves

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What type of container must be used for acid or alkali wastes?
a. Polyethylene Drums
b. Metal drums
c. Fiber Drums
d. Cloth container

Polyethylene Drums

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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.
a. Composting
b. Recycling
c. Bioremediation
d. Reducing

Composting

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A series of reference standards solutions that have known and accurate pH values at different temperatures used for pH meter calibration. a. Buffer Solutions b. QC Solutions c. pH solutions d. None of the above.

Buffer Solutions

. Law that states the linear relationship between absorbance and concentration of an absorbing species a. Beer-Lambert’s Law b. Charles Law c. Boyles 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. Uncertainty

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 a. 50.45 mL b. 50.27 mL c. 50.37 mL d. 50.17 mL

50.27 mL

It is a pure dry solid substance of known chemical composition used in the direct standardization of solution. a. primary standard b. secondary standard c. analytical standard d. indicator

primary standard

Sample preparation technique used prior to instrumental analysis of metals. a. acid digestion b. liquid-liquid extraction c. sieving d. clean-up

acid digestion

It is the closeness of the agreement between the result of a measured value and a true value. a. Accuracy b. Precision c. Mean d. Error

Accuracy

Which of the following chemicals may be used to neutralize waste containing caustic soda? a. Potassium Hydroxide b. Ammonia c. Hydrochloric Acid d. Buffer 10 Solution

Hydrochloric Acid

Which of the following are possible routes of exposure of the hazardous effect of waste? a. Inhalation b. Dermal c. Ingestion d. all of the above

all of the above

According to Revised DAO 04-36, the appropriate waste labels 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

Reliability of the results decreases with a decrease in the level or concentration of the: a. matrix b. analyte c. reactant d. product

analyte

. Properties of nitric acid making it the preferred acid for digesting samples for the analysis of metals. a. acts as a strong acid b. 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. 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

Quantitative chemical analysis of weighing a sample, usually of a separated and dried precipitate. 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. a. solvent b. solute c. mixture d. solution

solvent

Requirements of a primary standard. 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. gooch crucible b. Buchner funnel c. rotary evaporator d. rubber aspirator

Buchner funnel

. In chromatography, ________ is carried out on glass plates or strips of plastic or metal coated on one side with a thin layer of adsorbent. 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 d. compounds. e. all of the above

all of the above

A technique for separating mixtures into their components in order to analyze, identify, purify, and/or quantify the mixture or components. a. Spectroscopy b. Chromatography c. Gravimetry d. Titrimetry

Chromatography

A graph showing the detectors response as a function of elution time : band’s shapes, position, resolution 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+

c. H2S and OH−

Predict the products of the following acid-base reaction: NH3(aq) + HNO3(aq) → a. NH2OH(aq) + HNO2(aq) b. NH4NO3(aq) c. NH4OH(aq) d. no reaction takes place

NH4NO3(aq)

Insoluble impurities from solution during crystallization are removed by ____________ a. Drying b. c c. Heating d. Cooling

Filtration

Which of the following is not a common method used for purification? a. Sublimation b. Crystallisation c. Electrolysis d. Chromatography

Electrolysis

The solution of impure compound and solvent is concentrated to get ____________ a. Unsaturated solution b. Undersaturated solution c. Saturated solution d. Oversaturated solution

Saturated solution

Crystal phases can be interconverted by varying ____________ a. Temperature b. Pressure c. Size d. Viscosity

Temperature

Which of the following is not separated through distillation process? a. Acetone and water b. Aniline and chloroform c. Impurities in seawater d. Milk and water

Milk and water

Column chromatography is based on the principle of _______________ (this question appeared twice) a. Ion-exchange b. Exclusion principle c. Differential adsorption d. Absorption

Differential adsorption

Select the correct statement from the following options. a. The lesser the polarity of solute, more strongly it will be adsorbed on a polar surface b. The greater the polarity of solute, more weakly it will be adsorbed on a polar surface c. The greater the polarity of solute, more strongly it will be adsorbed on a polar surface d. All of the mentioned option

The greater the polarity of solute, more strongly it will be adsorbed on a polar surface

The elution power of a solvent is determined by ____________ a. Its overall polarity b. The polarity of the stationary phase c. The nature of the sample components d. All of the mentioned

All of the mentioned

The principle on which thin layer chromatography is based is that the ____________ a. Different compounds are absorbed on an absorbent to different degrees b. Different compounds are absorbed on an absorbent to same degrees c. Different compounds are adsorbed on an adsorbent to different degrees d. Different compounds are absorbed on an absorbent to same degrees

Different compounds are adsorbed on an adsorbent to different degrees

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 cellulose column d. All of the mentioned

All of the mentioned

Which type of chromatography is used for the structural analysis? a. Column chromatography b. Paper chromatography c. Partition chromatography d. Affinity chromatography

Paper chromatography

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 Elimination of undesirable substances from blood d. Separation of lipids, fatty acids and steroids

Elimination of undesirable substances from blood

Which of the following is the application of ion exchange chromatography? a. The softening of hard water b. The demineralisation 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 solid

The analysis of electromagnetic radiation scattered, absorbed or emitted by the molecule is called __________ a. Kaleidoscopy 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 option. 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

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. NMR Spectrometer c. IR Spectrometer d. Mass Spectrometer

AAS

An industrial source of alcohol. a. Coal b. Fats 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

What is the purpose of the apparatus shown below? a. Titrating b. Refluxing c. Filtering d. Distilling

Refluxing

In the analysis of a mixture by gas chromatography, which of the following gives the best clue as to whether the components can be analysed with any degree of accuracy? (Same concept) a. Column length b. Retention times c. Column temperature d. Flow rate of the carrier gas

b. 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

Why is there a need to separate halogenated waste from non-halogenated waste? a. Halogenated waste disposal is more costly. b. Non-halogenated wastes are more toxic. c. They are not compatible. d. They will react.

Halogenated waste disposal is more costly.

Organic peroxides are dangerous when a. Heated b. Concentrated c. Let ether, p-dioxane, THF, among others to vaporize d. All of the above

Halogenated waste disposal is more costly.

A 22/24 stopper is used in a volumetric flask. Which of the following is true? (Same concept as this). 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.

This type of glass is commonly used for laboratory glassware. a. Amber b. Quartz c. Fused silica d. Borosilicate

Borosilicate

This quality system standard is a general requirement for the competence of testing and calibration laboratories. a. GLP b. GMP c. ISO 9000 d. ISO/IEC 17025:2005

ISO/IEC 17025:2005

Which of the following can be disposed down the drain? a. 1 g/L PCl5 b. 1 M H2SO4 c. 200 g/L PCl5 d. None of the above

None of the above

Water is a good solvent for benzoic acid recrystallization.what is the correct preparation of benzoic solution for recrystallization. a. Add benzoic acid to minimum hot water with stirring b. Add room temp water to benzoic while stirring until dissolved c. Add maximum hot water to benzoic acid while stirring d. Add small portions of hot water to benzoic acid while stirring. Until dissolved

Add small portions of hot water to benzoic acid while stirring. Until dissolved

What is the name of RA 6969? a. Toxic Substances b. Toxic and Hazardous c. Toxic, Hazardous, and Nuclear Wastes d. Toxic, Hazardous and Nuclear Substances

Note: The choices were quite confusing. The correct one should be “Toxic Substances and Hazardous and Nuclear Wastes. C???

As P increase while T drops, intermolecular forces are evident, what is applicable? a. Ideal gas is still in effect b. Ideal gas must be replaced by van der Waals c. --- d. No change

Ideal gas must be replaced by van der Waals

In an ideal gas of volume V and temp T. What happens to T when volume is doubled under constant P? a. Increases b. Halved c. Remains the same d. Doubled

doubled

What type of reactions is hydrogen peroxide to water and oxygen? a. Decomposition b. Replacement c. Synthesis d. Combustion

Decomposition

How to balance H2O → O2 + H2 a. Change the coefficient of O2 to 2 b. Change the coefficient of H2 to 2 c. Change the coefficients of both H2O and H2 d. Change the coefficients of both H2O and O2 to 1/2

Change the coefficients of both H2O and H2

What compound is possibly shown in an infrared spectrum which has peaks of 3000 cm-1 and 1650 cm-1 a. Cyclohexane b. Benzene c. Acetone d. Cyclohexene

Cyclohexene

. If you are going to mass produce vitamin C, which standard should you subscribe in? a. Both A & B b. ISO 9000 c. Both B & C d. GMP

No idea since the choices were quite confusing. Maybe the choices were typo.

According to NFPA, what color refers to flammability. a. Blue b. Red c. Yellow d. White

RED

Complete name of the acronym MSDS

Material Safety Data Sheet

. A solution is _______ if more solute can dissolve in it. a. saturated b. supersaturated c. unsaturated d. concentrated

unsaturated

What is the molality of 6M H2SO4 solution? The density of the solution is 1.34 g/mL.

7.98

Solutions of metals and salts are ______ a. Insulator b. Conductor c. Polar d. Negative

conductor

Which of the following compounds have the same molecular and empirical formula?

Choices: Different structures of carboxylic acid

How many isomers do C5H12 have? a. 2 b. 3 c. 4 d. 5

Which of the ff requires the most energy for electronic transition? A. Alkyl halides B. Alkanes C. Carbonyl compounds D. Carboxylic compounds

Alkanes

Which of the following will cause the mass of the metal block to increase? A. Putting the block in a freezer B. Heating the block C. Measuring the mass of the block in Jupiter D. None of the above

None of the above

The process in which the relationship of the analytical response and the concentration of the analyte is established. A. Calibration B. Standardization C. Correlation analysis D. Normalization

Calibration

How much calcium chloride is needed to make .5L of .5M solution

27.7445g

The process that combines alcohol and carboxylic acid to form an organic compound and water is called

Esterification

250lb in SI unit

113 kilograms

When proteins are broken down by enzymes, the products are: a. amino acids b. carbohydrates c. fatty acids d. nucleic acid

amino acids

120. Which of the following is an acid? A. Milk of magnesia B. Apple juice

Apple juice

Which compound will rapidly decolorize bromine in CHCl3 A. hexane B. benzene C. 1-hexene D. cyclohexane

1-hexene

Presence of a functional group in a compound can be established by using: a. Chromatography b. IR Spectroscopy c. Mass Spectroscopy d. X Ray diffraction

IR Spectroscopy

The gas-solid chromatography is ____________ chromatography as per basic principle involved a. Exclusion b. Ion exchange c. Adsorption d. Absorption

c. Adsorption

What is the advantage of using ground glass joints when carrying out a chemical reaction? a. no purities are introduced in the reactions from corks or rubber stopper b. all joints are interchangeable and a good fit is assured c. glassware apparatus can easily be assembled d. All of the above

All of the above

A compound is known to decompose at its boiling point, which of the following methods can be used to purify this substance a. Simple distillation b. vacuum distillation c. liquid-liquid extraction d. fractional distillation e. steam distillation

steam distillation

How many possible isomers of alcohol does C4H8O have

Which compounds have both cis and trans isomers possible? Choices: Different organic compounds were given

choose which one is an alkene.

What type of cell converts chemical to electrical energy? A. Voltaic cell B. Galvanic cell C. Electrolytic cell D. Voltaic and galvanic cells

Voltaic and galvanic cells