CHEMICAL TECHNICIAN REVIEW TEST BANK - Laboratory Technology Flashcards by Abigail Peralta

Sampling type that eliminates questions of bias in selection.

A. composite
B. stratified
C. systematic
D. random

D. random

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When aqueous and nonaqueous liquids are combined, they usually form an immiscible mixture, such as oil and water. A ________ helps in separating the liquids into two samples.

A. pipet
B. beaker
C. separatory funnel
D. rotary evaporator

C. separatory funnel

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Mixtures of liquids and solids are usually separated prior analysis by

A. filtering
B. decantering
C. centrifuging
D. all of the above

D. all of the above

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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

D. All of the above

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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

B. Fusion technique

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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

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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

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Primary sample preparation method for organics.

A. Sonification
B. Acid-digestion
C. Extraction
D. All of the above

C. Extraction

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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

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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

C. glass and plastic

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The size of the sample taken for analysis depends on the concentration of the

A. analyte
B. specific tests
C. equipment to be used
D. all of the above

D. all of the above

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Equipment commonly used to homogenize the contents of an open beaker.

A. Magnetic stirrer
B. Ball and rod mills
C. V-blenders
D. Tube rotator

A. Magnetic stirrer

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The maximum holding time for acid preserved samples that will be subjected to determination of metals is __________.

A. 3 months
B. 1 week
C. 6 months
D. 48 hours

C. 6 months

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A fraction of the sample used in the final laboratory analysis.

A. composite sample
B. laboratory sample
C. sub-sample
D. a, b and c

B. laboratory sample

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A change in the analytical signal caused by anything in the sample other than analyte.

A. matrix effect
B. absorbance
C. interference
D. transmittance

A. matrix effect

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Medium containing analyte.

A. reactant
B. matrix
C. solute
D. reference material

B. matrix

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The total error of an analytical result is the sum of

A. sampling
B. analytical errors
C. sample preparation
D. all of the above

D. all of the above

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The holding time for samples for metal determination preserved using nitric acid, 4 mL of dilute 3:1 is _________.

A. 28 days
B. 2 weeks
C. 3 days
D. 1 year

A. 28 days

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When samples cannot be dried because they decompose at the temperatures necessary to drive off the water, the samples can be analyzed as _________.

A. wet basis
B. dry basis
C. received basis
D. all of the above

D. all of the above

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Organic components in solid samples are extracted from the matrix by continuously washing the solid with a volatile solvent in a specialized piece of glassware`

A. Soxhlet extraction
B. Ultrasonic extraction
C. Filtration
D. Rotary evaporation

A. Soxhlet extraction

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In liquid-liquid extraction, it is often necessary to determine which liquid is aqueous and which liquid is nonaqueous. To test the liquids, add a drop of water to the top layer. If the drop dissolves in the top layer, the top layer is

A. nonaqueous
B. aqueous
C. miscible
D. denser

B. aqueous

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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

B. analyte

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Process by which a sample population is reduced in size to an amount of homogeneous material that can be conveniently handled in the lab in which the composition is representative of the population.

A. selection
B. sampling
C. monitoring
D. segregation

B. sampling

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As a rule, the error in sampling and the sample preparation portion of an analytical procedure is considerably higher than that in the

A. methodology
B. treatment
C. preservation
D. subsampling

A. methodology

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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

Homogenization during sample preparation can be achieved using mechanical devices (e.g., grinders, mixers, slicers, blenders), enzymatic methods (e.g., proteases, cellulases, lipases) or chemical methods (e.g., strong acids, strong bases, detergents). A. mechanical devices (mixers, blenders, etc.) B. enzymatic methods C. chemical methods D. all of the above

D. all of the above

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

To increase/decrease analyte concentration, pre-concentration is needed for almost all trace analysis, ________ is used for the analysis of highly contaminated samples so the concentration falls within the calibration range. A. centrifugation B. separation C. dilution D. none of the above

C. dilution

Chemical derivatization is used to increase or decrease volatility for _________ analysis A. AAS B. GC and HPLC C. PCR D. none of the above

B. GC and HPLC

Acid digestion via hot-plate digestion or microwave-assisted is one way of sample preparation in the analysis of A. Total metal B. Bioactive compounds C. Alcohols D. Sugars

A. Total metal

GFAA (Graphite Furnace Atomic Absorption) do not use HCl since Cl- interferes. Diluted ______ acid is used. A. Phosphoric Acid B. Acetic Acid C. Nitric Acid D. Sulfuric Acid

C. Nitric Acid

Partitioning of analytes between water phase and organic phase A. Liquid-liquid Extraction B. Solid phase Extraction C. Ultrasonic Extraction D. Pressured Fluid Extraction (PFE)

A. Liquid-liquid Extraction

Calculate the equivalent weight and normality for a solution of 6.0 M H3PO4 given the following reactions: (1) H3PO4(aq) + 3OH- ⟶ PO43-(aq) + 3H2O(l) (2) H3PO4(aq) + 2NH3 ⟶ HPO42-(aq) + 2NH4+(aq) (3) H3PO4(aq) + F- ⟶ HPO42-(aq) + 3HF(aq) A. (1) 18N, (2) 12N and (3) 6N B. (1) 12N, (2) 18N and (3) 6N C. (1) 6N, (2) 12N and (3) 18N D. (1) 16N, (2) 12N and (3) 3N

A. (1) 18N, (2) 12N and (3) 6N

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

D. 0.214 m

The amounts of all constituents in the samples were determined A. Complete (or ultimate) analysis B. Partial analysis C. Elemental analysis D. All of the above

A. Complete (or ultimate) analysis

Implies that the constituent determined was present in high concentration A. Trace analysis B. Macro analysis C. Elemental analysis D. All of the above

B. Macro analysis

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

A chemical grade of highest purity and meets or exceeds purity standards set by American Chemical Society A. technical grade B. Laboratory grade C. Pure or practical graded D. ACS grade

D. ACS grade

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

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.

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

A student performs five titrations and obtains a mean result of 0.110 M, with a standard deviation of 0.001 M. If the actual concentration of the titrated solution is 0.100 M, which of the following is true about the titration results? A. Accurate but not precise B. Precise but not accurate C. Both accurate and precise D. Neither accurate nor precise

B. Precise but not accurate

How many grams of Sodium Persulfate (Na2S2O8) required to prepare a 1 L solution of Sodium Persulfate with concentration of 10% (w/v). This solution is widely used as oxidizing reagent for Total Organic Carbon analyzer (TOC). A. 100g of Sodium Persulfate B. 101g of Sodium Persulfate C. 102g of Sodium Persulfate D. 99g of Sodium Persulfate

A. 100g of Sodium Persulfate

A solution has been prepared by transfer 60 mL from Ortho-phosphoric acid 85 % (v/v) H3PO4 and dilute 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

Bidirectional harpoons or double arrows (⇆) should be used to indicate ________ reactions A. one sided B. resonance C. dynamic D. reversible

D. reversible

In the preparation of 1 liter of 1.0 N acid from 35% Hydrochloric Acid, what weight of the impure acid should be taken, assuming standardization in the recommended manner? Given: Normality (N1) = 2.0 eq.wt/li HCl %purity = 35% Volume = 1 liter Required: weight of impure acud (HCl) Solution: g = (1eq.wt.HCl/li×1mole/1eq.wt.HCl×36.45gHCl/mole)0.35 g = 101.29 A. 101.29 B. 113.29 C. 111.29 D. 124.89

111.29

A few ways in which solution composition can be described are as follows. A. Molarity B. Normality C. Molality D. All of the above

D. All of the above

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

Naphthalene (C10H8) is one of aromatic hydrocarbons measured by GC-MS. If molecular weight of naphthalene is 128.6 g/mol; how many milligrams are required to prepare 100 mL of 2,000 ppb stock standard solution of naphthalene from powder Naphthalene (purity of 91.5% w/w)? A. 2.18 B. 2.1858 C. 2.186 D. 2.1859

B. 2.1858

Used to measure volumes approximately, typically with errors of several percent except for one. A. Beakers B. Pipettes C. Reagent Bottles D. Graduated Cylinders

C. Reagent Bottles

Nitrate (NO3-) anion solution prepared by dissolving 3.0 g of KNO3 in 250 mL of water. What is the concentration of Nitrate ion, express the concentration in Molarity and ppm? A. 0.1187 M, 7359.05 ppm B. 0.1190 M, 7349.05 ppm C. 0.1107 M, 7459.00 ppm D. 0.1120 M, 7400.00 ppm

A. 0.1187 M, 7359.05 ppm

The number of formula mass of any solute dissolved in 1 liter of solution A. formality B. normality C. molality D. molarity

A. formality

A 0.217 g sample of HgO (molar mass = 217 g) reacts with excess iodide ions according to the reaction. Titration of the resulting solution requires how many mL of 0.10 M HCl to reach equivalence point? HgO + 4I- + H2O ⟶ HgI42- + 2OH- A. 1.0 mL B. 10 mL C. 20 mL D. 50 mL

C. 20 mL

If the theoretical yield for a reaction was 156 grams and I made 122 grams of the product, what is my percent yield? A. 78.2% B. 128% C. 19.0% D. none of these

A. 78.2%

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

A. primary standard

You have a stock solution of 15.8 M HNO3. How many mL of this solution should you dilute? using only a graduated pipette to make 100.0 mL of 0.250 M HNO3? A. 1.58 B. 1.582 C. 1.50 D. `1.583

A. 1.58

If 56.0 g of Li reacts with 56.0 g of N2, 93.63 grams of Li3N can be produced. How many grams of Nitrogen remains? What is the limiting reactant? A. 19.3 g Nitrogen B. 18.3 g N; Lithium C. 20.3 g Nitrogen D. 18.39; Lithium

B. 18.3 g N; Lithium

HCl cannot be a primary standard because of its gaseous form at room temperature, but its solutions may be standardized against anhydrous __________. A. NaSO4 B. Na2CO3 C. NaHCO3 D. All of the above

B. Na2CO3

When making a solution from a solid reagent, if necessary, dry the solid reagent on a clean, oven dried, watch glass at 105ºC for 2 hours and cool it in a desiccator. A. 121°C B. 105°C C. 80°C D. 118°C

B. 105°C

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

D. All of the above

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

B. equivalence

Property which depends on the number of particles dissolved in each mass of solvent. A. vapor pressure lowering B. boiling point elevation C. freezing point depression D. all of the above

D. all of the above

Boiling occur if the vapor pressure of the liquid is less than the atmospheric pressure. A. True B. False C. Not all the time D. Always

B. False

What is the relationship between the temperature and the solubility of a solid in a liquid? A. directly proportional B. inversely proportional C. no relationship D. geometric

B. inversely proportional

What is boiling point elevation? A. It is the difference between the boiling points of a pure solvent and a solution. B. It is the sum of the boiling points of a pure solvent and a solution. C. It is the difference between the boiling points of a pure solute and a pure solvent. D. It is the boiling point of a solution.

A. It is the difference between the boiling points of a pure solvent and a solution.

A membrane that allows the passage of solvent molecules through, but not solute molecules are called? A. animal membrane B. semipermeable membrane C. permeable membrane D. plant membrane

B. semipermeable membrane

The excess pressure required to stop the flow and keep the solution in equilibrium with the pure solvent is A. partial pressure B. vapor pressure C. osmotic pressure D. atmospheric pressure

C. osmotic pressure

The separation of a mixture of substances into pure components based on their differing solubilities is A. fractional distillation B. vacuum crystallization C. vacuum distillation D. fractional crystallization

D. fractional crystallization

Which has a lower freezing point? A. water B. NaCl C. NaCl solution D. all of the above

C. NaCl solution

The reactant which is present in the smallest stoichiometric amount, and which limits the amount of product that can be formed in a reaction is A. the limiting reagent B. the reagent with the least number of grams C. the excess reagent D. the reagent with the greatest number of grams

A. the limiting reagent

Which of the following hastens the rate of solution? A. pulverization B. scratching the sides of the container C. seeding D. cooling

A. pulverization

A polar solute usually dissolves in a polar solvent and a nonpolar solute usually dissolves in a nonpolar solvent. This is A. the solubility rules B. the “like dissolves like” rule C. Henry’s law D. Hund’s rule

B. the “like dissolves like” rule

A solution is _______ if more solute can dissolve in it. A. saturated B. supersaturated C. unsaturated D. concentrated

C. unsaturated

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

B. solubility

The normality of a solution is always _____________ the molarity. A. greater than or equal to B. greater than C. less than or equal to D. less than

A. greater than or equal to

Which of the following concentration units is independent of temperature? A. molarity B. normality C. molality D. percent volume

C. molality

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

A. beaker

Ambient laboratory conditions are not the same to standard conditions, therefore the volumes dispensed in volumetric glassware are often not the same as the manufacturer's specifications, but within some acceptable limits determined by the manufacturer. This slight variation in volume will cause an _________ error that are based on volume-volume or mass-volume concentrations. A. random B. systematic C. gross D. all of the above

B. systematic

Glass cuvettes are typically for use in the wavelength range of visible light, whereas fused quartz tends to be used for ____________ applications. A. microwave B. IR C. UV/visible D. none of the above

C. UV/visible

In this column type, the retention is governed by the interaction of the polar parts of the stationary phase and solute. A. reverse phase B. ion exchange C. column guard D. normal phase

D. normal phase

A stable light source in AAS analysis, which is necessary to emit the sharp characteristic spectrum of the element to be determined? A. Tungsten lamp B. Hollow cathode lamp C. Deuterium lamp D. Nerst blower

B. Hollow cathode lamp

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

Non-Polar Reverse phase and C8 (octyl bonded silica) are commonly used for hydrophobic Analytes in solid phase extraction. An example is A. C18 (octadecyl bonded silica) B. Resins C. Florisil D. Alumina

A. C18 (octadecyl bonded silica)

Filters that can be heated and used in gravimetric analysis. A. ordinary filter paper B. GFF C. sintered glass fibers D. none of the above

B. GFF

Objects cannot be weighed when hot or warm. But if you were to take a sample out and wait for it too cool it would pick up moisture like that so put it in ________. A. an oven B. a desicator C. at room temperature D. Fume hood

B. a desicator

Weighing to constant weight means a weighing difference of ±0.1mg using a calibrated analytical A. ±1.0 mg B. ±0.01 g C. ±0.01 mg D. ±0.1 mg

D. ±0.1 mg

The following are common desiccants except for ____________ A. Calcium Sulfate B. Ammonium Acetate C. Calcium Chloride D. Magnesium Oxide

B. Ammonium Acetate

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

A. porcelain crucible

In making standard solutions, ______ are used for measuring liquid with high accuracy. A. beakers B. volumetric flasks C. Erlenmeyer flasks D. Nessler’s tubes

B. volumetric flasks

Used for distillation or heating of liquids, allows uniform heating. A. round bottom flask B. Erlenmeyer flask C. test tube D. Florence flask

A. round bottom flask

Most popular burettes are 10 mL, 25 mL and 50 mL types. Which has the highest resolution? A. 25 mL B. 10 mL C. 50 mL D. All of the above

C. 50 mL

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

The nominal volume of water (or mercury) contained, or delivered by an article of volumetric glassware, at its reference temperature. A. capacity B. liter C. mL D. uL

A. capacity

In verification of laboratory glassware, ________ is usually measured in terms of the tolerance, which is the uncertainty in a measurement made with the glassware. Class A volumetric glassware has a lower tolerance than Class B. A. means B. accuracy C. difference D. precision

B. accuracy

Glass apparatus that are generally received with calibration certificates from suppliers. A. Class B B. Class A C. Erlenmeyer flasks D. Beakers

B. Class A

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

B. ultraviolet

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 the above.

D. All 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

C. infrared spectroscopy

The concentration at which the calibration curve departs from linearity by a specified amount. A. Limit of Blank B. Dynamic Range C. Limit of Linearity D. Limit of Quantitation

C. Limit of Linearity

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

What is the path of light through a spectrophotometer? A. meter, photodetector, filter, sample, light source B. meter, filter sample, photodetector, light source C. light source, filter, sample, photodetector, meter D. light source, sample, filter, photodetector, meter

C. light source, filter, sample, photodetector, meter

With a “standard” sample with a known absorbance and concentration and a measured absorbance, it is easy to determine an unknown concentration of †the same substance by. A. Beer’s Law B. Beer and Lambert’s Law C. Law of Mass Conservation D. None of the above

A. Beer’s Law

The highest apparent analyte concentration expected to be found when replicates of a blank sample containing no analyte are tested. A. Limit of Detection B. Limit of Blank C. Limit of Linearity D. Limit of Quantitation

B. Limit of Blank

Motion of the mobile phase through the stationary phase. A. Elution B. Retention time C. Eluent D. Elution time

A. Elution

A phase which sample is dissolved in may be gas, liquid, or supercritical fluid A. stationary phase B. reverse phase C. normal phase D. mobile phase

D. mobile phase

In spectrophotometric methods, the _________ isolates the specific spectrum line emitted by the light source through spectral dispersion. A. monochromator B. prism C. sample compartment D. detector

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 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 “modified” stationary phase where polar solutes run fast i.e., reverse order. A. Normal phase B. Reverse phase C. Mobile phase D. None of the above

B. Reverse phase

A graph showing the detectors response as a function of elution time: band’s shapes, position, resolution A. monitor display B. quality control curve C. calibration curve D. chromatogram

D. chromatogram

The pH meter glass probe has two electrodes; one is a glass sensor electrode and the other is a _______________electrode. A. reference B. anode C. cathode D. none of the above

A. reference

Conductivity could be determined using the distance between the electrodes and their surface area using Ohm's law but, for accuracy, a calibration is employed using ___________________of well-known conductivity. A. acid solution B. basic solution C. electrolytes D. buffer solution

C. electrolytes

The electrical conductivity of water is related to the concentration of dissolved ionized solids in the water or A. Total Suspended Solids B. Total Dissolved Solids C. Volatile Solids D. Total Solids

B. Total Dissolved Solids

At 510 nm, the iron Orth phenanthroline complex has a molar absorptivity of 1.2×104. What is the concentration of iron (in ppm) in a solution which gives an absorbance of 0.002 in a 1.00 cm path length cell? A. 7.3×10-3 ppm B. 8.3×10-3 ppm C. 9.3×10-3 ppm D. 6.3×10-3 ppm

C. 9.3×10-3 ppm

The light source used in the visible range to 340-1000 nm. A. deuterium B. nerst blower C. tungsten D. incandescent

C. tungsten

The % T of a solution in a 2.00 cm cell is 50. Calculate the %T of this solution in a 1.0 cm path length. A. 71 B. 19 C. 27 D. 20

A. 71

An air sampling canister was evacuated by the local fire dep’t and brought to the environmental lab for analysis. It was said that the sample was taken near the site where a rusty 55-gal drum was found by some children. A reported unpleasant smell near the site was reported. Results of gravimetric analysis of the gas in the canister: C – 40%, H- 6.7%, O – 53.33%. What is the liquid in the drum? A. CH2O B. CH3OH C. CH3CH2O D. None of the above

A. CH2O

A student must 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. takes the average of multiple measurements using the graduated cylinder. B. measures the liquid using a 25 mL graduated cylinder instead. C. estimates 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.

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 acceptor

B. a proton acceptor

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

D. an electron pair acceptor

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

A. proton donor

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: HCl(aq)+ NaOH(aq) ⟶ A. H3O+(aq) + OH- B. Na+(aq) + Cl-(aq) C. NaCl(aq) + H3O(l) D. No reaction takes place

C. NaCl(aq) + H3O(l)

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)

What effect will addition of excess of HCl have on the pH of a solution of NH3? A. increase in pH B. decrease in pH C. no effect D. cannot tell from the information

B. decrease in pH

What effect will addition of sodium acetate have on the pH of a solution of acetic acid? A. increase the pH B. decrease the pH C. no effect D. cannot tell from information given

A. increase the pH

A solution that causes only a relatively small change in pH upon addition of small amounts of acids and bases is A. saturated B. a salt C. a buffer D. unsaturated

C. a buffer

Which of the following is buffer? A. NaCl/NH4C B. NH3/NH4Cl C. NH3/CH3COOH D. CH3COOH/NaOH

B. NH3/NH4Cl

The conjugate base of acetic acid is A. HCOOH B. NH3 C. CH3COO- D. OH-

C. CH3COO-

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

The conjugate acid of ammonia is A. H3O+ B. NH4+ C. HCOOH D. OH-

B. NH4+

Effect produced by an ion, say from a salt, which is the same ion produced by the dissociation of a weak acid or base is called A. colloidal effect B. precipitation effect C. common ion effect D. ligand effect

C. common ion effect

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

B. Le Chatelier’s Principle

Water cannot function as which one of the following? A. a Bronsted acid B. a Bronsted base C. a Lewis acid D. a Lewis base

C. a Lewis acid

When a strong acid is titrated with a weak base, the pH at the equivalence point is A. basic B. acid C. neutral D. none of the above

B. acid

When a strong acid is titrated with a strong base, the pH at the equivalence point is A. basic B. acid C. neutral D. none of the above

C. neutral

When NH4Cl hydrolyzes, the resulting solution is A. acidic B. basic C. neutral D. none of the above

A. acidic

We have a 5.43×10−4 M solution of HNO3 at 25°C. What is the [OH−] in this solution? A. 1.84×10-11 M B. 5.43×10-10 M C. 5.43×10-4 M D. 3.67×10-6 M

A. 1.84×10-11 M

What is the pH of a 5.82×10−3 M solution of NaOH at 25°C? A. 4.76 B. 11.76 C. 7.00 D. 2.45

B. 11.76

The pH of a 0.20 M NH3 solution is Kb(NH3) = 1.8×10‒5 A. 0.70 B. 2.73 C. 11.28 D. 6.99

C. 11.28

The pH of a solution is 6.38. The hydrogen ion concentration is A. 4.17×10-7 M B. 4.17×10-6 M C. 6.38×10-16 M D. 0.638 M

A. 4.17×10-7 M

What is the [H3O+] of a 0.100 M solution of HCN at 25°C? Ka (HCN) = 4.0×10−10 A. 1.58×10-8 M B. 2.00×10-5 M C. 6.32×10-6 M D. 4.00×10-11 M

C. 6.32×10-6 M

A 0.200 M solution of an acid, HA, has a pH of 2.70 at 25°C. What is Ka for this acid? A. 2.21×10-4 B. 4.55×10-6 C. 1.99×10-4 D. 2.00×10-5

D. 2.00×10-5

What is the pH of a 0.52 M solution of CH3COONa at 25°C? Ka(CH3COOH) = 1.76×10−5? A. 9.23 B. 4.77 C. 9.37 D. 10.21

A. 9.23

Acids and Bases 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

The lining of the stomach contains cells that secrete a solution of HCl. Which drink would best alleviate heartburn (excess acid in the stomach)? A. milk, pH = 6.5 B. wine, pH = 3.8 C. diet soda, pH = 4.3 D. milk of magnesia, pH = 10.5

D. milk of magnesia, pH = 10.5

Which species are acting as Bronsted acids in the reaction below? A. H2O B. H2O and H3O+ C. H2O ND SO4-2 D. HSO4- and H3O+

D. HSO4- and H3O+

Which equation correctly describes the relationship between Kb and Ka for a conjugate acid/base pair? A. Kb = KwKa B. Kb = Ka/Kw C. Kb = Kw/Ka D. Kb = Ka + Kw

C. Kb = Kw/Ka

The following are observed characteristics of gases except for A. gases can be compressed by application of pressure B. gases diffuse and spontaneously mix with each other C. pressure exerted by a gas decrease with increase in temperature D. there is negligible attraction between particles of an ideal gas

C. pressure exerted by a gas decrease with increase in temperature

The standard pressure of the atmosphere at sea level is ____. A. 1 atm B. 760 torr C. 760 mmHg D. all of the above

D. all of the above

As altitude increases, air becomes less dense and A. pressure increases B. pressure decreases C. pressure remains the same D. none of the above

B. pressure decreases

Raising the temperature of an enclosed gas A. slows down the kinetic energy of the gas molecules B. decreases the momentum of the gas molecules C. forces the gas particles to collide with the walls harder D. decreases the volume of the gas

C. forces the gas particles to collide with the walls harder

At constant temperature and pressure, the rate of diffusion of a gas varies A. inversely as its density B. directly as its molecular mass C. directly as the square root of its density D. inversely as the square of its molecular mass

D. inversely as the square of its molecular mass

What are the standard temperature and pressure (STP) conditions for gas law problems? A. 760 atm, 0°C B. 760 mmHg, 273°C C. 760 mmHg, 273K D. 760 atm, 0K

C. 760 mmHg, 273K

If the temperature of a confined gas is doubled, while the volume is held constant, what will happen to the pressure? A. it will be doubled B. it will be half as large C. it will be four times as large D. cannot be determined

A. it will be doubled

What happens to the volume of a fully inflated balloon when it is taken outside on a cold day? A. its volume decreases B. it remains the same C. its volume increases D. its volume becomes equal to zero

A. its volume decreases

The process by which a gas under pressure escapes from a compartment of a container to another by passing through a small opening is called A. effervescence B. effusion C. diffusion D. sublimation

B. effusion

As a bubble of air rises from a diver’s helmet to the surface of the water, it continuously expands. What law is illustrated? A. Dalton’s law B. Avogadro’s law C. Boyle’s law D. Charles’ law

C. Boyle’s law

A gas is in a steel tank at 100 atm pressure. When the tank is opened to the atmosphere, the gas suddenly expands, increasing its volume by 10%. This illustrates. A. Dalton’s law B. Boyle’s law C. Charles’ law D. Gay-Lussac’s law

B. Boyle’s law

Water boils at a lower temperature such as on top of a mountain than at sea level. This illustrates. A. Boyle’s law B. Boyle’s law C. Charles’ law D. Avogadro’s law

C. Charles’ law

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 25.0°C? A. 0.191 L B. 19.1 L C. 2.28 L D. 22.8 L

C. 2.28 L

What is the molar mass of an unknown gas if 1.60 grams of that gas occupies a volume of 2.24 L at STP? A. 16.0 g/mol B. 35.7 g/mol C. 81.0 g/mol D. 160 g/mol

A. 16.0 g/mol

The volume of a certain gas sample is 235 ml when collected over water at a temperature of 25°C and a pressure of 698 mm Hg. What will be the volume of this gas when measured dry at standard conditions? The vapor pressure of water at this temperature is 23.8 mm Hg. A. 197 mL B. 191 mL C. 223 mL D. 265 mL

B. 191 mL

Which of the following represents the largest gas pressure? A. 1.0 atm B. 1.0 Pa C. 1.00 mm Hg D. 1.0 kPa

A. 1.0 atm

The total volume of an average adult lungs when expanded is about 6 liters. Calculate the pressure of oxygen inhaled if 0.05 mole of oxygen is needed to fully fill a pair of average adults lungs at a normal body temperature of 37°C. A. 0.0253 atm B. 2.58 atm C. 0.212 atm D. 0.308 atm

C. 0.212 atm

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

A fatal condition known as “bends” occurs when a diver ascends too quickly to the surface of the water. This is due to A. nitrogen in the blood boiling off rapidly as its partial pressure decreases, forming bubbles in the blood B. lack of oxygen in water at depths of more than 15 meters C. the solubility of oxygen gas is very much decreased at greater depths D. the solubility of oxygen decreases in the blood as the diver ascends

A. nitrogen in the blood boiling off rapidly as its partial pressure decreases, forming bubbles in the blood

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

CHEMICAL TECHNICIAN REVIEW TEST BANK - Laboratory Technology Flashcards

Sampling and Sample Preparation | Qualify Laboratory Equipment / Apparatus / Glassware | Instrumental Analyses | Instrumental Analyses | Gases | (169 cards)