PBE Chemical Technician

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

Electrophiles are

a. electron deficient species

b. electron rich species

c. electrically neutral species

d. positively charged ion

a. 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

b. 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?

a. Acid treatment using oxidation

b. Fusion technique

c. dissolution using ultrasound & appropriate solvent

d. Simple dissolution

b. 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. ash

b. analyte

Glass container is not suitable for

a. inorganic trace analyses

b. oil and grease determination

c. microbiological analyses

d. all of the above

a. 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

d. Potassium hydrogen phthalate

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%

d. 5.10%

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

The HPLC column type in which molecules are separated according to size.

a. Ion exchange

b. size exclusion

c. normal phase

d. reverse phase

b. 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.

a. porcelain crucible

b. evaporating dish

c. beaker

d. all of the above

a. porcelain crucible

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

a. 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.

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

d. 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.

d. 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

d. 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

b. A catalyst speeds up both the forward and reverse reaction rates

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

c. 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

a. 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

a. 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.

a. 0.0524

b. 0.0552

c. 0.0465

d. 0.00052

a. 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.

a. sieving

b. pulverizing

c. macerating

d. milling

a. sieving

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

c. Rubber gloves

What type of container must be used for acid or alkali wastes?

a. Polyethylene Drums

b. Metal drums

c. Fiber Drums

d. Cloth container

a. Polyethylene Drums

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

a. Composting

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

a. 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

a. 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

b. 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

c. 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

b. 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

a. primary standard

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

a. Accuracy

Sample preparation technique used prior to instrumental analysis of metals.

a. acid digestion

b. liquid-liquid extraction

c. sieving

d. clean-up

a. acid digestion

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

c. 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

d. 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

d. All of the above

Sampling type that eliminates questions of bias in selection

a. composite

b. stratified

c. systematic

d. random

d. random

Reliability of the results decreases with a decrease in the level or concentration of the:

a. matrix

b. analyte

c. reactant

d. product

b. 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

d. 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

d. 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

d. 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

b. 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

c. 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

a. 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

d. All of the above

Used for vacuum filtration using filter paper.

a. gooch crucible

b. Buchner funnel

c. rotary evaporator

d. rubber aspirator

b. 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

d. 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

d. 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

b. 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

d. 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

b. 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

b. NH4NO3(aq)

Which of the following is not a common method used for purification?

a. Sublimation

b. Crystallisation

c. Electrolysis

d. Chromatography

c. Electrolysis

The solution of impure compound and solvent is concentrated to get ____________

a. Unsaturated solution

b. Undersaturated solution

c. Saturated solution

d. Oversaturated solution

c. Saturated solution

Insoluble impurities from solution during crystallization are removed by ____________

a. Drying

b. Filtration

c. Heating

d. Cooling

b. Filtration

Crystal phases can be interconverted by varying ____________

a. Temperature

b. Pressure

c. Size

d. Viscosity

a. 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

d. 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

c. 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

c. 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

d. 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

c. Different compounds are adsorbed on an adsorbent to different degrees

Which type of chromatography is used for the structural analysis?

a. Column chromatography

b. Paper chromatography

c. Partition chromatography

d. Affinity chromatography

b. 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 cellulose column

d. All of the mentioned

d. 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

c. 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

d. All of the mentioned

The quantitative analysis is done using ____________

a. Ion exchange chromatography

b. Thin layer chromatography

c. Gas chromatography

d. Liquid chromatography

c. 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

b. Freezing point of liquid

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

a. Kaleidoscopy

b. Astronomy

c. Spectroscopy

d. Anatomy

c. 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

d. 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

c. 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

d. 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.

a. 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

a. AAS

An industrial source of alcohol.

a. Coal

b. Fats

c. Sugar

d. Ether

c. Sugar

What is the most common isotope of hydrogen?

a. H has only one isotope

b. Protium

c. Deuterium

d. Tritium

b. 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.

d. 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

d. Borosilicate

What is the purpose of the apparatus shown below?

a. Titrating

b. Refluxing

c. Filtering

d. Distilling

b. Refluxing

What type of GHS hazard symbol is shown below?

a. Corrosive

b. Flammable

c. Oxidizer

d. Explosive

a. Corrosive

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?

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

d. 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.

a. 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

d. All of the above

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

d. None of the above

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

d. ISO/IEC 17025:2005

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

b. 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

d. Doubled

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

d. 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"

What type of reactions is hydrogen peroxide to water and oxygen?

a. Decomposition

b. Replacement

c. Synthesis

d. Combustion

a. 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

c. 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

d. 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

d. GMP

According to NFPA, what color refers to flammability.

a. Blue

b. Red

c. Yellow

d. White

b. Red

Complete name of the acronym MSDS.

a. ---

b. ---

c. Material Safety Data Sheet

d. ---

c. Material Safety Data Sheet

A solution is _______ if more solute can dissolve in it.

a. saturated

b. supersaturated

c. unsaturated

d. concentrated

c. unsaturated

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

m= 8 mol/kg

Solutions of metals and salts are ______

a. Insulator

b. Conductor

c. Polar

d. Negative

b. Conductor

How many isomers does C5H12 have?

a. 2

b. 3

c. 4

d. 5

b. 3

Which of the ff are limitations of Lambert-Beer's Law?

a. Scattering of light due to particles

b. Fluorescence of sample

c. Non-monochromatic radiation

d. All of the above

d. All of the above