ChTLE 2024 Analytical Chemistry Pre-Board Exam (4/4)

Chemicals of sufficiently high quality to be suitable for use in some syntheses. Organic chemicals of this grade may contain small amounts of intermediates, isomers, or homologs.

A. USP or NF grade

B. HPLC grade

C. Technical Grade

D. Practical grade

D.

When an open bottle of _________________ sits next to an open bottle of ammonium hydroxide, thick white fumes form.

A. Nitric acid

B. Hydrochloric acid

C. Sulfuric acid

D. Hydroflouric acid

B.

What acid is a highly corrosive mineral acid and is also known as aqua fortis (Latin for "strong water") and spirit of niter, is:

A. Nitric acid

B. Hydrochloric acid

C. Sulfuric acid

D. Hydrofluoric acid

A.

____________________ diffuses through skin and is especially bad when it gets under the fingernails.

A. Nitric acid

B. Hydrochloric acid

C. Sulfuric acid

D. Hydrofluoric acid

D.

155. _____________________ is used to dissolve the sample for the Kjeldahl analysis.

A. Nitric acid

B. Hydrochloric acid

C. Sulfuric acid

D. Hydrofluoric acid

C.

A mixture of concentrated HNO3 and HCl in the ratio of 1:3 HNO3:HCl is:

A. muriatic acid

B. oil of vitriol

C. aqua regia

D. none of the above

C.

If a given procedure calls for a pure methyl alcohol of the highest grade, then the ___________ should be used.

A. ACS grade or AR grade

B. Laboratory grade

C. Technical grade

D. USP grade

A.

What classical method of analysis is characterized by the fact that the measurement of weight is the primary measurement, usually the only measurement made on the sample, its components, or its reaction products.

A. Volumetric method

B. Titrimetric method

C. Gravimetric method

D. Instrumental method

C.

What is the percent loss on drying if a sample weighs 4.5027 g before drying and 3.0381 g after drying?

A. 32.527%

B. 32%

C. 32.53%

D. 32.5%

A.

The onset of a phase transition in a small region which can be the formation of a bubble or of a crystal from a liquid.

A. Precipitation

B. nucleation

C. reprecipitation

D. crystallization

B.

Refers to a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances.

A. Supersaturation

B. nucleation

C. reprecipitation

D. none of the above

A.*

What type of balance uses an electromagnet to balance the object to be weighed on a single pan?

A. macro balance

B. electronic balance

C. mechanical balance

D. none of the above

B.

A balance that is used to obtain four or five digits to the right of the decimal point in the analytical laboratory is called the (precision is ±0.1 or ±0.01 mg).

A. macro balance

B. electronic balance

C. mechanical balance

D. analytical balance

D.

Refers to the process by which a balance is checked to see if the weight obtained for an object is correct.

A. Validation

B. verification

C. calibration

D. maintenance check

C.

Gravimetric analysis methods proceed with the following steps:

A. The weight or volume of the prepared sample is obtained.

B. The analyte is either physically separated from the sample matrix or chemically altered and its derivative is separated from the sample matrix.

C. The weight of the separated analyte or its derivative is obtained.

D. All of the above

D.

This is an example of a loss through volatilization (evaporation) under temperature conditions at which water would volatilize.

A. loss on drying

B. loss on ignition

C. loss on filtration

D. none of the above

A.

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 a _________ error that are based on volume-volume or mass-

volume concentrations.

A. Random

B. systematic

C. gross

D. all of the above

B.

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.

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.

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.

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.

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.

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.

Objects cannot be weighed when hot or warm. But if you were to take a sample out and wait for it to cool it would pick up moisture like that so put it in ________.

A. an oven

B. a dessicator

C. at room temperature

D. fumehood

B.

The following are common desiccants except for _______.

A. Calcium Sulfate

B. Ammonium Acetate

C. Calcium Chloride

D. Magnesium Oxide

B.

During ignition for ashing, muffle furnaces that go up to 1100 deg-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.

In making standard solutions, ______ are used for measuring liquid with high accuracy.

A. Beakers

B. volumetric flasks

C. Erlenmeyer flasks

D. Nesslers Tubes

B.

Used for distillation or heating of liquids, allows uniform heating.

A. round bottom flask

B. Erlenmeyer flask

C. test tube

D. Florence flask

A.

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.

Used for vacuum filtration using filter paper.

A. gooch crucible

B. Buchner funnel

C. rotary evaporator

D. rubber aspirator

B.

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.

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.

In verification of laboratory glassware, ________ is usually measured in terms of the tolerance, which is the uncertainty in a measurement made with the glassware.

A. Mean

B. accuracy

C. difference

D. precision

B.

Glass apparatus that are generally received with calibration certificates from suppliers.

A. Class B

B. Class A

C. Erlenmeyer flasks

D. Beakers

B.

Refers to repeated drying steps until two consecutive weights agree to within a specified precision, such as having two consecutive weights that do not differ by more than 0.25%.

A. loss on drying

B. taring

C. loss on ignition

D. constant weight

D.

Total solids involve measuring a volume of the water or wastewater into a pre-weighed _____________________.

A. evaporating dish

B. gooch crucible

C. sintered crucible

D. filter crucible

A.

Equipment that work by the sedimentation principle, where the centripetal acceleration is used to separate substances of greater and lesser density.

A. Rotary evaporators

B. Centrifuges

C. Reciprocating shakers

D. Rotary shakers

B.

Also known as droppers or eye droppers, are used to transfer small quantities of liquids. They are usually glass tubes tapered to a narrow point, and fitted with a rubber bulb at the top.

A. Pasteur pipettes

B. graduated pipettes

C. capillary tubes

D. Bulb pippetes

A.

Small, cylindrical plastic containers with conical bottoms, typically with an integral snap cap. They are used in molecular biology and biochemistry to store and centrifuge small amounts of liquid.

A. Eppendorf tubes

B. capillary tubes

C. microfuge tubes

D. Falcon Tubes

C.

A device used in chemical and biochemical laboratories for the efficient and gentle evaporation of solvents. The system works because lowering the pressure lowers the boiling point of liquids, including that of the solvent.

A. Rotary evaporators

B. Centrifuges

C. Reciprocating shakers

D. Rotary shakers

A.

An essential item used in the distillation of liquid mixtures so as to separate the mixture into its component parts, or fractions, based on the differences in their volatilities.

A. Condenser

B. reflux apparatus

C. fractionating column

D. rotary flask

C.

Boiling chips are also known as:

A. boiling stones

B. boileezers

C. anti-bumping granules

D. all of the above

D.

All proteins absorb electromagnetic radiation of wavelength around 190 nm, which corresponds to a 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.

Chromatography is used to:

A. Separate two or more compounds based on their polarities.

B. Separate two or more compounds based on their masses.

C. Separate two or more compounds based on how strongly they interact with other compounds.

D. all of the above.

D.

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.

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.

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.

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.

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. Lambert's Law

C. Faraday's Law

D. None of the above

A.

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.