AC-2021 Flashcards by potatochips ~

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

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Electrophiles are

a. electron-deficient species
b. electron-rich species
c. electrically neutral species
d. positively charged ions

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 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

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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. dash

analyte

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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

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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

Potassium hydrogen phthalate

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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]

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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]

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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

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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

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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

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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

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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

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, 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

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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

The solubility of gases in water decreases with increasing temperature

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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. Pulverizing
B. Macerating
C. Milling
D. Sieving

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. Disposable plastic gloves

Rubber gloves

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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

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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 human-like product

A. Composting
B. Recycling
C. Bioremediation
D. Reducing

Composting

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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

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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

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

All of the above

Which of the following can be disposed down the drain? A. 1 g Cl- B. 1 M HCl C. 200 g L-1 PCl5 D. None of the above

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

ISO/IEC 17025-2005

As P increases 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 (Z) gas. C. No change. D. None of the above.

Ideal gas must be replaced by van der Waals (Z) gas.

In an ideal gas of volume V and temperature T, what happens to T when volume is doubled at constant P? A. Increases B. Halved C. Remains the same D. Doubled

Doubled

Water is a good solvent for benzoic acid recrystallization. What is the correct method for preparing the benzoic solution for recrystallization? A. Add benzoic acid to minimum hot water with stirring until dissolved. B. Add maximum hot water to benzoic acid while stirring. C. Add small portions of hot water to benzoic acid while stirring until dissolved. D. None of the above.

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

What is the name of RA 69697? A. Toxic Substances Act B. Toxic and Hazardous Waste Act C. Toxic, Hazardous, and Nuclear Wastes Act D. Toxic, Hazardous, and Nuclear Substances Act

Toxic Substances and Hazardous Nuclear Waste

What type of reaction is hydrogen peroxide decomposing 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 at 3000 cm?¹ and 1650 cm?¹? A. Cyclohexane B. Benzene C. Acetone D. Cyclohexene

Cyclohexene

According to NFPA, what color refers to flammability? A. Blue B. Red C. Yellow D. White

Red

Complete name of the acronym MSDS. A. Material Safety Data Sheet B. Material Safety Documentation Sheet C. Material Safety Declaration Sheet D. Material Safety Data Statement

Material Safety Data Sheet

What is the term for a solution that can dissolve more solute? A. Saturated B. Supersaturated C. Unsaturated D. Concentrated

Unsaturated

Solutions of metals and salts are: A. Insulators B. Conductors C. Polar D. Negative

Conductors

How many isomers does C5H12 have? A. 2 B. 3 C. 4 D. 5

B. 3

Which of the following 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

All of the above

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

Alkanes (only contains sigma bonds which are lower in energy than pi bonds) - single bond

The process in which the relationship of the analytical response and concentration is established is called: A. Calibration B. Method validation C. Co-elution analysis D. Normalization

Calibration

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

27.7 g

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 that combines alcohol and carboxylic acid to form an organic compound is called:

Esterification

When proteins are broken down by enzymes, the products are: A. Amino acids B. Carbohydrates C. Fatty acids D. None of the above

Amino acids

Which of the following is an acid? A. Milk of magnesia B. Apple juice C. Water D. Baking soda

Apple juice (is acidic due to presence of citric and malic acid)

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 as per basic principle involved is called: A. Exclusion B. Ion Exchange C. Adsorption D. Absorption

Adsorption

What is the advantage of using ground glass joints when carrying out a chemical reaction? A. No impurities are introduced in the reactions from corks or rubber stoppers. 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

What type of cell converts chemical energy into electrical energy? A. Voltaic Cell B. Galvanic Cell C. Electrolytic Cell D. Voltaic and Galvanic Cells

Voltaic and Galvanic Cells

Chromatography separates mixture of dyes on the basis of their . A. density B. polarity (solubility) C. gravity D. boiling point

polarity (solubility)

The concentration of a solution is known to be 0.101 M. A student determines the concentration to be 0.088 M, 0.087 M, and 0.089 M for each titration performed. Which of the following best describes these results? A. The results are accurate but not precise. B. The results are precise but not accurate C. The results are neither accurate nor precise. D. The results are both accurate and precise. E. The results are not enough information is given to determine accuracy or precision.

The results are precise but not accurate

What is the stoichiometry of EDTA with metal ions? A. It is 1:6, because EDTA is a hexaprotic weak acid with six distinct acid dissociation values. B. It is 1:4, because EDTA has four binding sites upon loss of the four carboxylic acid protons. C. It is 1:2, because EDTA has two binding sites upon loss of the two ammonium protons. D. It is 1:1, because EDTA forms a cage-like structure around the metal ion. E. It is dependent on the metal ion present.

It is 1:1, because EDTA forms a cage-like structure around the metal ion.

Which variable in Beer's law represents how well a chemical species absorbs light at a given wavelength? A. c - concentration B. e - molar absorptivity coefficient C. A - absorbance D. b - path length of the sample E. ? - wavelength

molar absorptivity coefficient

Why must solutions with high concentrations be diluted prior to analysis via Beer's Law? A. The relationship between absorbance and concentration is not linear at high concentrations. B. The detector will reach its detection threshhold. C. The photon source is too weak to provide accurate results. D. The molar absorptivity of a compound is dependent on its concentration. E. There is no need to work with dilute concentrations; any concentration will work.

The relationship between absorbance and concentration is not linear at high concentrations.

In order for a compound to be IR active, it must undergo which of the following? A. A change in polarizability B. A change in dipole moment C. Emission of an electron D. Transfer of an electron E. Metal-ligand charge transfer

A change in dipole moment

How does turbidimetry differ from nephelometry? A. Turbidimetry measures the decrease in transmittance of incident radiation; nephelometry measures the intensity of scattered radiation. B. Nephelometry measures the decrease in transmittance of incident radiation; turbidimetry measures the intensity of scattered radiation. C. Nephelometry measures the total metal ion, or inorganic, content; turbidimetry measures total organic content. D. Turbidimetry measures the total metal ion, or inorganic, content; nephelometry measures total organic content.

Turbidimetry measures the decrease in transmittance of incident radiation; nephelometry measures the intensity of scattered radiation.

Fill in the blank. The relationship between the analyte concentration and the intensity of measured radiation from thermal excitation methods, such as a flame or plasma, is . A. Linear B. Exponential C. Parabolic D. Polynomial E. Asymptotic

Linear

Why is a hollow cathode tube lamp necessary in atomic absorption? A. Because cathode lamps are cheaper to operate and maintain B. Because continuous spectrum lamps do not emit at the proper intensity C. Because the width of an atom's absorption band is narrow D. Because continuous spectrum lamps cause ionization of the molecules

Because the width of an atom's absorption band is narrow

If a compound has a retention time of 5.30 minutes with a baseline width of 0.64 minutes on a 2.0 m silica gel column, what is the average height of a theoretical plate? A. 1.8 mm/plate B. 15 mm/plate C. 29 mm/plate D. 0.24 mm/plate E. 2.7 mm/plate

1.8 mm/plate H = L/N N = 16(tr/W)^2 H = height N = no. of theo plates tr = retention time Wb = baseline width L - length of the column

"Tailing" of a chromatographic peak is a result of which of the following? A. Interactions of the solute with the stationary phase B. Overloading the column with sample C. Interactions between the stationary and mobile phases D. Too many theoretical plates E. Small theoretical plate heights

Interactions of the solute with the stationary phase

What is the process of the loss of an electron called? A. Oxidation B. Reduction C. Transference D. Sublimation E. Neutralization

Oxidation

Which of the following is a substrate that is oxidized? A. Cationic species B. Anionic species C. Neutral species D. Reducing agent E. Oxidizing agent

Reducing agent

Where does the reduction reaction occur? A. At the anode B. At the cathode C. Within the potentiometer D. Within the salt bridge E. Within the bulk solution

At the cathode [Oxidation - Anode Reduction - Cathode]

Which of the following statements about the standard hydrogen electrode, the calomel electrode, and the silver/silver chloride electrode is true? A. These electrodes combine to make a complete electrochemical cell. B. These electrodes are typically used as reference electrodes. C. These electrodes are typically used as working (indicator) electrodes. D. These electrodes are examples of membrane electrodes. E. These electrodes have the same electrochemical potential.

These electrodes are typically used as reference electrodes.

Pre-treatment of solid samples prior analysis. A. Leaching and extraction of soluble components B. Filtering of mixtures of solids, liquids and gases to leave particulate (solid) matter C. Grinding D. All of the above

All of the above

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

Containers that should not be used for dry ashing because the elevated temperatures exceed the melting point of these materials A. zirconium B. platinum C. Glass and plastic D. porcelain

Glass and plastic

How would you prepare 500.0 mL of 0.2500 M NaOH solution starting from a concentration of 1.000 M? A. Transfer 125 mL from initial solution (1.000 M) and complete with solvent to 500.0 mL. B. Transfer 121 mL from initial solution (1.000 M) and complete with solvent to 500.0 mL. C. Transfer 122 mL from initial solution (1.000 M) and complete with solvent to 500.0 mL. D. Transfer 112 mL from initial solution (1.000 M) and complete with solvent to 500.0 mL.

Transfer 125 mL from initial solution (1.000 M) and complete with solvent to 500.0 mL.

The method of standardization can be used if a _______________ reacts quantitatively with the reagent needed in the standard solution. A. primary standard B. secondary standard C. working standards D. intermediate solution

primary standard

Blank samples are prepared so that you have a measure of the amount that needs always to be added to or subtracted from the end point to achieve the ________point. A. titration error B. equivalence C. accuracy D. precision

equivalence

The maximum amount of solute that will dissolve in a definite amount of solvent to produce a stable system at a specified temperature is called A. dilution B. solubility C. saturation D. concentration

solubility

Under the Lewis concept of acids and bases, an acid is A. a proton donor B. a proton acceptor C. a hydroxide donor D. an electron pair donor

an electron pair donor (base: proton acceptor acid: electron pair donor)

A principle stating that if stress is applied to a system at equilibrium, the equilibrium is shifted in the direction that tends to reduce the stress. A. Heisenberg Uncertainty Principle B. Le Chatelier’s Principle C. Hund’s Rule D. Debye-Huckel Principle

Le Chatelier’s Principle

In recording laboratory results, the following shall be done, except: A. Use permanent ink B. When an error is committed, put multiple lines to cross out the wrong data C. Always indicate the date of analysis D. Record all necessary details including qualitative observations

When an error is committed, put multiple lines to cross out the wrong data

In sample acceptance, which of the following shall be checked? A. sample density B. sample integrity C. amount of sample D. both sample integrity and amount of sample

both sample integrity and amount of sample

A sample comprising two or more increments selected to represent the material being analyzed. A. grab sample B. composite sample C. laboratory sample D. none of the are

composite sample [grab - single taken at specific time composite - w/increments lab - prepared]

The following are good sampling practices except: A. Take several increments and composite them to form the sample. B. If possible, mix the material before getting the sample. C. Collect the sample in a container made if material that will chemically react with the sample. D. Sample frequently enough to allow for the identification of process cycles.

Collect the sample in a container made if material that will chemically react with the sample.

Light sensitive samples should be collected in a/an __________ container. A. polyethylene bottle container B. polypropylene container C. amber bottle container D. volumetric flask

amber bottle container

The dilution of concentrated acid is an exothermic process. It is best to: A. place the flask in a hot water bath. B. add ice cold water instead of room temperature water. C. place the flask in a cold-water bath. D. place the flask in a freezer with a temperature of -20ºC

place the flask in a cold-water bath.

Which of the following is a cause of contamination during the sample preparation? A. Sample contained in a required container following the precautions specified in the sampling method. B. Sample preparation apparatus is cleaned and washed according to requirements of sampling method. C. Carryover of previous sample due to uncleaned sample preparation apparatus. D. None of the given choices.

Carryover of previous sample due to uncleaned sample preparation apparatus.

The following are different types of sample preservation except: A. freezing B. acidification C. reagent addition D. filtration

filtration

Sample preparation technique used prior to instrumental analysis of metals. A. acid digestion B. liquid-liquid extraction C. sieving D. clean-up

acid digestion

Preservation technique for water samples intended for metals determination that cannot be analyzed immediately A. Acidify with 1mL HNO3 to pH<2 B. Adjust pH to>11.5 with NaOH, C. Filter and preserve with zinc acetate D. add PbCO3

Acidify with 1mL HNO3 to pH<2

For an aqueous solution of hydrochloric acid (HCl) the pH was found to be 4.18 units. What is the concentration of HCl in this solution? A. 2.2 x10-3 M B. 1.4 x 10-3 M C. 4.8 x 10-4 M D. 6.6 x 10-5 M

6.6 x 10-5 M (pH=-log[H+]) 10^-pH

What is the pH of a 0.015 M solution of potassium hydroxide (KOH)? A. 1.8 B. 12.2 C. 8.8 D. 13.1

12.2 (KOH concentration = 0.015 M pOH = -LOG(0.015) pH = 14 - pOH)

Which one of the following statements is true? A. A strong electrolyte solution is a solution that always contains a high concentration of an acid or base. B. The strength of an acid can be influenced by the solvent into which it is placed C. In aqueous solution a strong acid will dissociate to form a strong conjugate base and together these form a conjugate pair. D. pH 7 is considered to be neutral pH at all temperatures

The strength of an acid can be influenced by the solvent into which it is placed A. false: can be any that dissociates into ions C. false: strong acid dissociates completely D. false: pH varies w temp

When talking about energy levels in an atom, what is an "excited state"? A. The highest energy state of an atom. B. Any level higher than the ground state. C. The lowest energy state of an atom. D. When an atom loses an electron E. When the atom rests.

Any level higher than the ground state.

The Beer-Lambert Law... A. Relates absorbance, concentration, path length and molar absorption coefficient B. Tells us the volume of the sample C. Relates frequency and wavelength D. Allows us to calculate how conjugated the system is

Relates absorbance, concentration, path length and molar absorption coefficient

Absorption occurs at... A. All wavelengths in the spectrum B. A characteristic wavelength dependent on the molecule C. The UV region D. The visible region

A characteristic wavelength dependent on the molecule

Which of the following statements most accurately describes UV-Vis spectroscopy? A. Inside a spectrophotometer, the beam is split into two where one beam is used as a reference and the other beam is used to cause interference with the reference. B. UV-Vis spectroscopy can be used to measure the kinetics or the rate constant of a reaction. C. For molecules containing ? or non-bonding electrons, the larger the HOMO-LUMO gap, the longer the wavelength the compound absorbs. D. The absorbance of a compound is proportional to the concentration of the sample and inversely proportional to the path length according to Beer’s Law.

UV-Vis spectroscopy can be used to measure the kinetics or the rate constant of a reaction.

A pure substance will have spot(s) on a chromatogram A. 0 B. 1 C. 2 D. 3

1 [single consistent retention factor]

Nickel is isolated from base ore samples by digesting the sample with aqua regia (USEPA Method 200.7, 1994). The concentration of Ni in the supernatant is determined by atomic absorption using an air-acetylene flame. The following calibration data and sample absorbance was obtained: Concentration (M) Absorbance 0.00 0.00 0.100 0.006 0.200 0.013 0.300 0.020 Sample 0.016 What is the concentration of the unknown in mol/L? A. 0.234 B. 0.301 C. 0.126 D. 0.099

0.234 (do linear regression where y = abs and x = conc) (slope = abs/conc)

The separation of a two-component mixture measured Dtr = 8.5mm, wA=wB=12.0mm. What can be said about the separation of the two peaks? A. The resolution is good. B. The resolution is not good. C. The resolution cannot be computed. D. The plate number is good.

The resolution is not good. Rules Rs = Dtr/(wA+wB) Good if greater than 1.5

The free EBT indicator is________in color at pH 10. A. Wine red B. Blue C. Violet D. Orange E. None of the above

Blue • pH < 6 (acidic): Red • pH 6-7 (neutral): Violet • pH > 7 (basic, around pH 10): Blue

To determine the molar mass of a solid monoprotic acid, a student titrated a weight sample of the acid with standard NaOH. Which of the following could lead to a larger molar mass? I. Failure to rinse all the acid from the weighing container into the beaker. II. Addition of more water than was needed to dissolve the acid. III. Addition of some base beyond equivalence point A. I only B. II only C. I and III only D. II and III only E. I, II and III

I only

In the titration of a weak acid with a strong base, at the equivalence point A. pH = 7.0 B. pH <7.0 C. pH > 7.0 D. none of these E. pH = pOH

pH > 7.0 • pH = 7: Strong acid - strong base • pH < 7: Strong acid - weak base • pH > 7: Weak acid - strong base • pH = pOH: Neutral solution

A high equivalent weight is desirable for compounds used as primary standards because A. such compound are generally easier to purify. B. such compounds are generally hygroscopic C. such compounds generally react with 1:1 stoichiometry D. large compounds generally contain less surface area. E. weighing errors are generally minimized.

weighing errors are generally minimized.

56. Which of the following statements is true? A. A masking agent prevents one species from interfering in the analysis of another. B. In EDTA titration, an auxiliary complexing agent prevents metal ions from precipitating in the absence of EDTA. C. Metal ion indicators are compounds whose color changes when they bind to a metal ion. D. All of these. E. None of these.

Metal ion indicators are compounds whose color changes when they bind to a metal ion.

Which of the following is not a desirable property of an indicator to be used in a complexometric titration that involves EDTA? A. The indicator should be a Lewis base. B. The indicator should bind more tightly to the analyte metal than EDTA does. C. The complexation reaction between the indicator and the analyte metal should be reversible. D. The uncomplexed form of the indicator should be a different color than the indicator- metal complex.

The indicator should bind more tightly to the analyte metal than EDTA does.

Commercial reagent grade H2SO4 is about A. 12 M B. 15 M C. 18 M D. 24 M E. None of the given choices

18 M

A 50.0 mL solution containing Zn2+ was treated with 25 mL of 0.0452 M EDTA. The excess EDTA needed 29.2 mL 0.0123 M Mg 2+ to reach the equivalence point. What was the molarity of Zn2+ solution? A. 0.0154 M B. 0.0422 M C. 0.0211 M D. 0.0308 M E. None of the choices

0.0154 M • Moles Zn²⁺ = Total moles EDTA - Moles of Mg²⁺ • Calculate molarity of Zn²⁺

Which of the following can be used for strong acid-base titrations? A. Phenolphthalein B. Methyl orange C. Bromocresol green D. Methyl red E. All of the these

All of the these

Which changes to this galvanic cell increase the measured potential? I. Increasing [Cu2+] in the Cu/Cu2+ half-cell to 0.50 M II. Adding Cl– to the Ag+/Ag half-cell until [Cl–] = 0.01 M A. I only B. II only C. Both I and II D. Neither I and II

Neither I and II

When 1.06 mmol of 1-pentanol and 1.53 mmol of 1-hexanol were separated by gas chromatography, they gave relative peak areas of 922 and 1 570 units, respectively. When 0.57 mmol of pentanol was added to an unknown containing hexanol, the relative chromatographic peak areas were 843:816 (pentanol:hexanol). How much hexanol did the unknown contain? A. 0.46 mmol B. 0.47 C. 0.50 D. 0.52

0.47 • Ax/x = F(As/s) • Calculate response factor (F) • Use formula to find the unknown value of hexanol

A mixture of benzene, toluene, and methane was injected into a gas chromatograph. Methane gave a sharp spike in 42 s, whereas benzene required 251 s and toluene was eluted in 333 s. Find the capacity factor for each solute. A. Benzene = 5.0; Toluene = 6.9 B. Benzene = 6.9; Toluene = 5.0 C. Benzene = 1.39; Toluene = 1.33 D. Benzene = 1.33; Toluene 1.39

Benzene = 5.0; Toluene = 6.9 (K= [Tr-To]/To) (251-42/42 = 5) Tr = retention time To = unretained peak

It is the time the analyte spends in the stationary phase. A. Retention time B. Relative retention C. Adjusted retention time D. Unadjusted retention time

Adjusted retention time

The use of electrodes to measure voltages that provide chemical information is called? A. Voltammetry B. Amperometry C. Potentiometry D. Conductivity

Potentiometry

A scientific instrument that measures the hydrogen ion activity in water-based solutions. A. Conductivity apparatus B. Standard Hydrogen Electrode C. pH meter D. None of these

pH meter

The transmittance of a 0.010 M solution of a compound in a 0.100 cm pathlength cell is T = 8.23%. Find the absorbance and the molar absorptivity. A. A = 2.16; e = 2.16 x 103 M-1 cm-1 B. A = 1.08; e = 1.08 x 103 M-1 cm-1 C. A = 1.08; e = 0.54 x 103 M-1 cm-1 D. A = 0.54; e = 1.08 x 103 M-1 cm-1

A = 1.08; e = 1.08 x 103 M-1 cm-1 A = -logT = -log(0,0823) Beer Lamberts [A = ecL) A = absorbance e = molar absorptivity c = conc L = pathlength

Which statement is correct about the electrochemical cell represented here? Ag | Ag+ || NO3–, NO | Pt A. NO undergoes oxidation at the anode. B. The major purpose of the Pt is to act as a catalyst. C. The Ag electrode decreases in mass as the cell operates. D. The voltage of the cell can be increased by doubling the size of the Ag electrode.

The Ag electrode decreases in mass as the cell operates.

Which technique is preferred for delivering a solid into a pre-weighed beaker for weighing? A. Transfer more of the reagent than is needed to the beaker. Return the excess to the bottle with a spatula. B. Transfer the desired amount of solid from the reagent bottle by holding the neck of the open bottle over the beaker and tapping the bottle. Then weigh the beaker and solid. C. Weigh a spatula, scoop the desired amount of solid from the bottle, transfer it to the beaker and reweigh the spatula. D. Weigh a piece of filter paper, tap the neck of the bottle to transfer solid to the filter paper, weigh the filter paper and transfer the solid to the beaker.

Transfer the desired amount of solid from the reagent bottle by holding the neck of the open bottle over the beaker and tapping the bottle. Then weigh the beaker and solid.

What is the molarity of KI in a solution that is 5.00% KI by mass and has a density of 1.038 g·cm-3? A. 0.0301 M B. 0.313 M C. 0.500 M D. 0.625 M

0.313 1. Assume mass of KI = 5g 2. Calc Volume (m/density) 3. Calc mol of KI 4. mol/volume

Which compound is least soluble in water? A. CH3CH2CH2F B. CH3CH2CH2NH2 C. CH3CH2CH2OH D. CH3CH2CH2COOH

CH3CH2CH2F overall structure is primarily hydrocarbon (nonpolar)

Which statement is correct about a system at equilibrium? A. The forward and reverse reactions occur at identical rates. B. The concentrations of reactants must equal the concentrations of the products. C. The concentrations of reactants and products can be changed by adding a catalyst. D. The concentrations of reactants and products are not affected by a change in temperature.

The forward and reverse reactions occur at identical rates.

What is the minimum concentration of cyanide contained in a waste to be classified it under A101(wastes containing cyanide)? A. 20 ppm B. 100 ppm C. 200 ppm D. 1000 ppm

20 ppm

The curve represents the titration of A. a diprotic acid. B. two monoprotic acids with the same Kas but different concentrations. C. two monoprotic acids with different Kas but the same concentrations. D. two monoprotic acids with different Kas and different concentrations.

two monoprotic acids with different Kas and different concentrations.

A student prepares a 100 mL aqueous solution containing a small amount of (NH4)2SO4 and a second 100 mL solution containing a small amount of NaI, then mixes the two solutions. Which statement describes what happens? A. Both compounds dissolve and remain in solution when the two solutions are mixed. B. Both compounds dissolve initially but NH4I precipitates when the solutions are mixed. C. Both compounds dissolve initially but Na2SO4 precipitates when the solutions are mixed. D. The NaI dissolves but the (NH4)2SO4 does not. There is no change upon mixing

Both compounds dissolve and remain in solution when the two solutions are mixed.

A solution of concentrated aqueous ammonia is added dropwise to 1 mL of a dilute aqueous solution of copper(II) nitrate until a total of 1 mL of the ammonia solution has been added. What observations can be made during this process? A. The colorless copper(II) nitrate solution turns blue and yields a dark blue precipitate. B. The colorless copper(II) nitrate solution yields a white precipitate which turns dark blue upon standing. C. The light blue copper(II) nitrate solution yields a precipitate which redissolves to form a dark blue solution. D. The light blue copper(II) nitrate solution turns dark blue and yields a dark blue precipitate.

The light blue copper(II) nitrate solution turns dark blue and yields a dark blue precipitate.

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

If the coefficients for a reaction are all multiplied by 2, the equilibrium constant will be A. equal to Kc x 2 B. equal to Kc over 2 C. unchanged D. equal to Kc^2

equal to Kc^2

Which of the following could NOT be added together to make a buffer solution? A. NaOH and CH3COOH B. CH3COONa and CH3COOH C. NaOH and CH3COONa D. NH4Cl and NH3

NaOH and CH3COONa 1. strong base - weak acid = buffer 2. salt - weak acid/weak base = buffer 3. salt - strong base = no buffer 4. strong acid - strong base = no buffer

For the reaction A(l) + 3B(g) + C(g) + 2D(g) ?H= -175kJ, what will happen if temperature of the system is increased? A. Kc will decrease B. none of the given options C. ?H will decrease D. Kc will increase

Kc will decrease

Calculate the equivalent weight and normality for a solution of 6.0 M H3PO4 given the following reactions: (a) H3PO4(aq) + 3OH–(aq) PO43–(aq) + 3H2O(l) (b) H3PO4(aq) + 2NH3(aq) HPO42–(aq) + 2NH4+(aq) (c) H3PO4(aq) + F–(aq) H2PO4–(aq) + HF(aq) A. 18 N, (b) 12 N and (c) 6N B. 12 N, (b) 18 N and (c) 6N C. 6 N, (b) 12 N and (c) 18N D. 16 N, (b) 12 N and (c) 3N

18 N, (b) 12 N and (c) 6N Normality = n(protons donated) x M(conc)

Requirements of a primary standards. 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

A food scientist has a sample of a plant oil and wants to determine if the oil contains saturated or unsaturated fatty acids. Which of the following spectroscopic techniques would be most useful for this purpose? A. ultraviolet spectroscopy B. visible spectroscopy C. infrared spectroscopy D. mass spectroscopy

infrared spectroscopy

All proteins absorb electromagnetic radiation of wavelength around 190 nm, which corresponds to an excitation in the protein molecule. In which region of the spectrum is this wavelength found? A. X-ray B. ultraviolet C. Visible D. Infrared

ultraviolet radiowaves (>1mm) microwaves(1mm to 1m) infrared (700nm to 1mm) visible light(380 nm to 700 nm) uv (10nm to 400 nm) xrays(0.01nm to 10 nm) gamma rays(<0.01nm)

In maintenance and storage of pH meters, which of the following procedure shall not be done? A. To keep the electrode bulb moist during storage, store the electrode in distilled water. B. Rinse pH electrodes in between measurements. C. Blot the electrode dry after rinsing the pH electrodes. D. Mild soap solution may be used in general cleaning of the electrodes

To keep the electrode bulb moist during storage, store the electrode in distilled water.

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 Matrix Spike: influence of matrix on perf Matrix Duplicate: Evaluate precision. Method Blank: Ensure no contamination. Reagent Blank: Ensure reagent purity.

Minimum concentration of a substance that can be measured and reported with 99% confidence that the analyte concentration is greater than zero A. Limit of Quantitation B. Lower Control Limit C. Lower Warning Limit D. Method Detection Limit

Method Detection Limit

What equation relates the expression of the equilibrium constant in terms of pressure and concentration? A. ideal gas equation B. van’t hoff equation C. Arrhenius equation D. Molarity

ideal gas equation

The holding time for samples for metal determination preserved using nitric acid, 4 mL of dilute 3:1 is A. 28 days B. 3 days C. 2 weeks D. 1 year

28 days

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

What is the molality of solution made by dissolve 25 g of NaCl in to 2.0 Liter of water. Assume the density of water d = 1.0 g/mL (= kg/L). A. 0.210 m B. 0.250 m C. 0.211 m D. 0.214 m

0.214 m Molality = mol/kg

Transfer 125 mL from initial solution (1.000 M) and complete with solvent to 500.0 mL. (C1V1 = C2V2)

On the multi-colored chemical label, Yellow represents A. Fire Hazard B. Health Hazard C. Reactivity Hazard D. Personal Protective Equipment

Reactivity Hazard

Which of the following should not be done in using a cuvette? A. Use a brush to clean the insides of the cuvette B. Fill the cuvette about 3/4 full of the solution you wish to test. C. Wipe the outside of the cuvette with a lint-free, soft tissue to remove any moisture or fingerprints from the outside surface. D. Do not clean your cuvettes in an ultrasonic cleaning bath.

Use a brush to clean the insides of the cuvette

In cases of acid spills, which of the following can be applied to the spill before treating it with adsorbent material? A. Sodium bicarbonate B. Water C. Acetic acid D. Sodium bisulfate

Sodium bicarbonate (is weak base that can neutralize acids)

Which is not a volumetric glassware? A. Erlenmeyer flask B. burette C. pipette D. volumetric flask

Erlenmeyer flask (Volumetric glassware is designed for precise measurements of volume)