131 Questions
Solvent extraction is more effective when the extraction is repeated with
small solvent
The insoluble impurities during recrystallization are removed by
hot gravity filtration
Calculate the percent yield if 0.85 g of aspirin is produced in the reaction of 1.00 g of salicylic acid with excess acetic anhydride. (no. 43 reviewer)
65%
During recrystallization, 0.85 g of crude aspirin was dissolved in a suitable solvent and after filtration and drying, 0.68 g of crystals were recovered. Calculate the % recovery.
80%
Which of the following is NOT separated using distillation?
milk and water
Steam baths are often used to heat volatile, non-aqueous, flammable solvents because of the following EXCEPT
Overheating is possible
The beads in a fractional column are for
vapors to condense
Fractional distillation is a process of separation of which of the following?
two miscible liquids
What is the advantage of steam distillation?
Reduces decomposition of temperature-sensitive compounds
Which of the following is NOT true about steam distillation?
very short extraction times
Which of the following is the correct way to determine the boiling point of an unknown compound?
Boiling a compound and placing the thermometer in the refluxing vapor.
The principle of TLC is that
Different compounds are adsorbed on an adsorbent to different degrees.
Which of the following statements about visualization during TLC is TRUE?
All of the above.
Amino acids can be detected by spraying the stationary phase with ninhydrin solution. This can be done in
paper chromatography
A substance is analyzed by paper chromatography, giving the chromatogram shown. What is the Rf value of the substance represented by the spot at 8.0 cm?
0.75
Karl Fischer titration, which determines trace amounts of water in a sample, uses which electrochemical method?
Coulometry
Which of the following is NOT a common method used for purification?
Electrolysis
Method of passing the sample through a metal or plastic mesh of a uniform cross-sectional area to separate particles into uniform sizes.
sieving
In the decomposition and dissolution of solids during sample preparation, which of the following is expensive and often the last resort?
fusion technique
Sample preparation technique used prior to instrumental analysis of metals.
acid digestion
In handling acid wastes, what type of protective gloves should be used?
rubber gloves
The following are the minimum requirements for hazardous waste storage facilities EXCEPT
Enclosed and should not be ventilated.
It is a hazardous waste characteristic which applies to wastes that have the potential to contaminate groundwater if improperly disposed of. These materials are regulated as hazardous waste due to their potential to leach out specific toxic substances in a landfill.
toxicity
What should you do when a waste container has a minor leak?
Transfer to another container
According to NFPA, what color refers to flammability?
red
Which of the following can be disposed down the drain?
None of the above
The following are good sampling practices EXCEPT
Collect the sample in a container made of material that will chemically react with the sample.
Organic peroxides are dangerous when
All of the above
When using a fume hood, all of the following must be done EXCEPT
Using the hood as a storage area for volatile chemicals when appropriate storage cabinet is not available.
According to the GHS, which of the following is NOT under the pictogram “Gas Cylinder”?
explosive gas
A technical document, which is GHS compliant, that contains all the information related to the health hazard, storage, precautionary measures, emergency procedures, etc. when handling chemicals.
Safety Data Sheet
Chromatography is used to
All of the above
Which type of chromatography is used for structural analysis?
Paper chromatography
Which of the following can be separated using column chromatography?
chlorophylls and carotenoids
Affinity chromatography is used for the analysis and isolation of
all of the mentioned
Which of the following is useful for the separation of low molecular weight gases?
Gas-solid chromatography
The analysis and separation of industrial products like soap and synthetic detergents is done using
Gas chromatography
Ion exchange particles carry fixed positive or negative charges. A sulfonic acid type resin has SO3–H+ groups were H+ can be exchanged for
cations
A graph showing the detector’s response as a function of elution time, band’s shapes, position, and resolution.
chromatogram
A technique for separating mixtures into their components in order to analyze, identify, purify, and/or quantify the mixture or components.
chromatography
Which of the following is NOT an application of high performance liquid chromatography?
Elimination of undesirable substances from blood
Quantitative analysis can be done using
Gas chromatography
Which of the following statements about spectroscopic methods is correct?
Spectroscopic methods require less time and less amount of sample than classical methods.
Which of the following demonstrates proper drying of cuvette?
blot on absorbing towel or tissue paper and allow to air dry
Which of the following is NOT a limitation of Beer-Lambert’s law?
Beer-Lambert’s law does not form the quantitative basis for all types of absorption spectroscopy.
A graphical representation of measuring signal as a function of quantity of analyte.
calibration curve
Which of the following compounds would show the longest wavelength max in its UV spectrum? (see mock exam no. 57)
III
Which species of the following is used to bombard with the sample for which mass spectroscopy has been performed?
electrons
Which of the following molecules will NOT show an infrared spectrum?
CO2
In the past, IR spectra had to be acquired one wavelength at a time, which took a long time. Today spectra can be acquired faster due to the
Fourier Transfer algorithm which allows to scan all frequencies at once
What compound is possibly shown in an infrared spectrum with peaks of 3000 and 1650 cm-1?
cyclohexene
NMR spectroscopy indicates the chemical nature of the __________ and spatial positions of __________.
Nuclei, neighboring nuclei
In which species are all the carbon atoms sp2 hybridized?
C2H4
What is the hybridization of the carbon atom in a carboxyl group?
sp²
In which species Is the carbon-nitrogen bond the shortest? (SEE MOCK EXAM NO. 65)
IV
How many different compounds have the formula C5H12?
3
How many different alcohols (not including stereoisomers) have the molecular formula C₄H₁₀O?
4
For which compound are the empirical and molecular formulas the same?
C6H5COOH
Which is the correct molecular formula of the following molecule? (SEE MOCK NO.69)
II
Which is the correct IUPAC name of the following compound? (SEE MOCK NO.71)
5-bromo-3-ethylhept-3-ene
Identify the incorrect statement regarding cycloalkanes.
They have tetrahedral bond angles
Which has the highest boiling point? (SEE MOCK NO.73)
III
Which of the following reactions will consume the most oxygen?
All the given compounds win consume the same amount of oxygen.
Which set of reagents can perform the following reaction? (SEE MOCK NO. 75)
O3, Zn/CH3COOH
Which of the following is NOT a reagent for hydrogenation of an alkyne?
BH3/H2O2, NaOH
When ethyne is subjected to ozonolysis, what is the end product?
formic acid
Which of the compounds below will react readily with chlorine by addition? I. C2H2 (ethyne) II. C2H4 (ethene) III. C6H6 (benzene)
I and II only
What is the order of reactivity of the following compounds in EAS? I. benzene II. toluene III. phenol IV. benzoic acid
IV < I < II < III
What are the reagents needed in bromination of benzene via EAS?
Bromine and FeBr3
Which of the following is NOT true for SN1 reactions?
They occur through a single step concerted reaction.
A low concentration of nucleophile favors
Neither SN1 nor SN2
Which statement(s) about substitution reactions are correct? I. The reaction between NaOH and 1-chloropentane predominantly follows an SN2 mechanism II. The reaction between NaOH and 2-chloro-2-methylbutane predominantly follows an SN2 mechanism. III. The reaction between NaOH with 1-chloropentane occurs at a slower rate than with 1-bromopentane
I and III
Which of the following alcohols would be most soluble in water?
Propanol
Which compound is a tertiary alcohol? (SEE MOCK N0. 85)
I
The gentle oxidation of ethanol produces which of the following product?
II. ethanoic acid
The major reason that phenol is a better Bronsted acid than cyclohexanol is
the pi electrons stabilize the phenoxide ion by resonance.
Which compound is NOT an ether? (SEE MOCK NO.88)
II
Which compound is NOT an aldehyde? (SEE MOCK NO. 89)
III
What is the IUPAC name for CH₃CH₂CH₂CH₂CHO?
pentanal
Which of following Is produced when hydrogen is reacted with 2-butanone? (NO ANSWER)
tertiary
Which of these compounds contain a carboxy group?
propanoic acid
The smell of rancid butter is due to the presence of butyric (butanoic) acid. What is the formula for this compound?
C4H8O2
Which family of compounds is most frequently used as flavoring agents?
esters
Calculate the percent yield when 0.5 mol of acetic acid reacts with 1 mol of alcohol produces 0.25 mol of ethyl acetate.
50%
Which compound is a tertiary amine? (SEE MOCK N0. 96)
IV
Which of the following compounds are basic?
amines
The most notable difference between a saturated and an unsaturated fat containing the same number of carbon atoms is that the saturated fat
melts at a higher temperature.
When proteins are broken down, they are converted to
amino acids
Molecular oxygen is highly soluble in the blood because
the hemoglobin molecule can bind up to four oxygen molecules.
Water is soluble solvent for the recrystallization of benzoic acid. How should be addition of the solvent?
Add small portions of hot water to benzoic acid while stirring until benzoic acid dissolves.
The organic liquid in steam distillation vaporizes at
A lower temperature than its boiling point
Column chromatography is based on the principle of
Differential adsorption
The components of the mixture in the column chromatography are eluted in order of
increasing polarity and increasing distribution ratio
A simple fractional tube is packed with which of the following?
Glass beads
The chromaplate or thin layer chromatography plate is made up of
Glass
Retardation factor is the ratio of
Distance moved by substance from baseline to distance moved by the solvent from baseline
Which of the following is FALSE regarding galvanic cells?
The reactions taking place are non-spontaneous
A cell is prepared by dipping a copper rod in 1 M CuSO4 solution and an iron rod in 2 M FeSO4 solution. Identify the anode and cathode.
Anode-iron; cathode-copper
Beer’s Law states that
Absorbance is proportional to the path length and concentration of the absorbing species
Which of the following is the principle of Atomic Absorption Spectroscopy?
Radiation is absorbed by non-excited atoms in vapor state and are excited to higher states.
Which of the following statements about mass spectroscopy is(are) correct?
all of the above
The region of electromagnetic spectrum for NMR is
Radio frequency
Which of the following is(are) application(s) of ion exchange chromatography?
All of the above
Which of the following is widely used for the separation of specific biomolecules? This relies on the highly specific binding between an analyte and its counterpart.
Affinity chromatography
What must be done to the solid samples for it to be introduced into the column without using solid injection syringes in gas chromatography
Dissolved in volatile liquids
Which of the following is NOT an ideal characteristic of a detector used in gas chromatography?
Sensitive to the changes in the flow rate of a carrier gas
Which of the following detectors is widely used to detect environmental samples like chlorinated pesticides and polychlorinated biphenyls?
Electron capture detector
Which of the following is NOT true about the guard column used in liquid chromatography?
It allows entry of particles that cause precipitation upon contact with stationary or mobile phase
Which of the following are not used in liquid or high performance liquid chromatography?
Capillary column
Which treatment method is NOT typically used to remove organic compounds?
Thermal
Segregation of waste organic solvents is very important because
All of the given answers
Which method is considered an unacceptable means of disposing waste?
All methods given are unacceptable
Which is the correct procedure for mixing acid and water?
Pour acid into water
Which of these compounds exist as cis and trans isomers?
1-chloropropene
Which compound will rapidly decolorize CHCl3 ?
1-hexene
Baeyer’s reagent is used to characterize alkenes. Which of the following is Baeyer’s reagent?
Aqueous solution of potassium permanganate
In what way does the reactivity of CH3C☰CH differ from CH3CH=CH2 ?
Propyne is deprotonated by NaNH2 while propene is not.
Which of the following is an aromatic compound?
Styrene
Which of the following is the most activating in electrophilic aromatic substitution?
-NH2
Which of the following is the rate determining step in electrophilic aromatic substitution?
Addition of the electrophile in benzene's π bond to form carbocation
Which of the following CANNOT be a product of the reaction of benzene with CH3Cl and AlCl3 ?
Isopropyl benzene
Alkyl halides are very reactive towards nucleophiles because
They have a electrophilic carbon and a good leaving group
SN2 means
One-step nucleophilic substitution involving both alkyl halide and nucleophile
Which of the following alkyl halides can undergo both SN1 and SN2 reactions?
(CH3)2CHX
Which of the following reactions are favored by polar aprotic solvent?
SN2 reactions
Which compound has the highest boiling point?
CH3CH2CH2OH
Which of the following reactions will NOT produce aldehydes?
Dehydration of secondary alcohols
Carbon is found in the highest oxidation state in which of these classes of organic compounds?
Carboxylic acids
Which reaction could occur between acetic acid and ethanol?
Esterification
Which of the following reactions can be used to distinguish between phenol and carboxylic acids?
Aqueous FeCI3
Under the Bronsted concept of acids and bases, a base is
proton acceptor
Test your knowledge on solvent extraction, recrystallization, yield calculation, and distillation in chemistry. Questions cover topics like percent yield, percent recovery, impurity removal, and solvent choice for heating.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
