OC-2019 Flashcards
Which of the following compounds has an Ionic bond?
I. H2O
II. NH4Cl
III. CH3Cl
IV. CH3Li
A. II
B. IV
C. I
D. III
II
electronegativity > 1.7 = ionic
How many hydrogen atoms are in one molecule of propene?
A. 4
B. 3
C. 6
D. 8
6
CnH2n
In which species are all the carbon atoms considered to be sp2 hybridized?
l. C2H2
II. C2H4
Ill. C3H8
IV. C4H10
A. IV
B. Il
C. I
D. Ill
II
Sp3 - alkane
sp2 - alkene
sp - alkyne
How many different compounds have the formula C5H12?
A. 5
B. 2
C. 4
D. 3
3
C5H12 - 3
C4H10O - 4
In which species Is the carbon-nitrogen bond the shortest?
I. CH3NH2
II. CH2NH
Ill. (CH3)4N+
IV. CH3CN
A. Il
B. I
C. IV
D. Ill
IV
Bond Order = Bond Strength = 1/Bond Length
Bond length is inversely proportional to the bond order
What Is the hybridization of the carbon atom in a carboxyl group?
A. sp
B. sp3
C. sp2
D. dsp3
sp2
Carboxyl - C double bond O
Sp2 = alkene
Functional Group:
Alcohol
Ether
Amine
Aldehyde
Ketone
Carboxylic Acid
Ester
Amide
REVIEW!!
Which of the following hydrocarbon has the lowest boiling point?
l. C4H10
ll. CH4
Ill. C6H6
IV. C2H6
A. IV
B. II
C. I
D. III
II
higher C atoms/cyclic = high BP
high molecular weight = high IMF = high BP
How many different alcohols have the molecular formula C4H10O?
A. 2
B. 4
C. 3
D. 5
4
Which compound Is expected to be most soluble in water at 25oC
I. N2 (g)
II. O2 (g)
Ill (C2H5)2NH (l)
IV. C2H5OC2H5 (l)
A. III
B. IV
C. I
D. II
III
- Protic [-OH, -NH, -FH]
- Aprotic [-O, -N, -F]
- Non-polar [O2, N2, CH4]
The gentle oxidation of ethanol (CH3CH2OH) produces ______
A. ethanal, CH3CHO
B. ethanoic acid, CH3CO2H
C. carbon monoxide, CO
D. carbon dioxide, CO2
ethanal
primary alcohol -> aldehyde -> carboxylic acid
secondary alcohol –> ketone
tertiary alcohol –> no reaction
The following compounds have very similar molar masses. What would be the correct order when they
are arranged in order of increasing strength of their intermolecular forces.
l. C3H8
Il. CH3OCH3
III. CH3CH2OH
A. II < I < III
B. III < I < II
C. I < II < III
D. III < II < I
I < II < III
Intermolecular Forces: HB > Dipole-dipole > Van der Waals
What is the position of the bromine atom relative to the methyl group in 3-bromotoluene?
A. meta
B. para
C. ortho
D. trans
meta
mono –> 1
ortho –> 1, 2
meta –> 1, 3
para —> 1, 4
Which combination of reactants produces an ester?
A. aldehyde and potassium permanganate
B. acid and alcohol
C. acid and aldehyde
D. alcohol and aldehyde
acid and alcohol
In crystallization, the solution which is obtained after filtration is the
A. clear solution
B. colloidal solution
C. suspended solution
D. None of the given answers
clear solution
In crystallization, the crystal phases can be Inter-converted by varying ______
A. temperature
B. pressure
C. viscosity
D. size
temperature
Which separation technique is based in the volatility of the compounds to be separated?
A. solvent extraction
B. distillation
C. paper chromatography
D. filtration
distillation
Fractional distillation is different from distillation because of the presence of a _______
A. Fractionating column
B. Condenser
C. Conical flask
D. Distillation flask
Fractionating column
A common measure of efficiency in a fractionating column is the
A. length of the condenser used in the setup
B. number of distillation types
C. number of components in the solution
D. number of theoretical plates in the column
number of theoretical plates in the column
Five grams an organic solid was dissolved in 100 mL of distilled water. Which of the following extraction
methods can remove the largest amount of organic solid from an aqueous solution?
A. Extract the aqueous solution with a 150-mL portion of ether.
B. Extract the aqueous solution with three 50-mL portions of ether.
C. Extract the aqueous solution with a 150-mL portion of acetic acid.
D. Extract the aqueous solution with three 50-mL portions of acetic acid.
Extract the aqueous solution with three 50-mL portions of ether.
Which of the following funnels should be used to filter hot mother liquor during recrystallization?
A. Buchner funnel
B. Hirsch funnel
C. Long stem funnel
D. Short stem funnel
Short stem funnel
short stem/stem less - hot gravity filtration
buschner funnel - suction/vacuum filtration
What is the key step in a recrystallization process?
A Taking the melting point of wet crystals
B. Dissolving the solid in a large quantity of cold solvent
C. Allowing the hot solution to cool slowly and let crystals grow
D. Removing the soluble impurities by vacuum filtration
Allowing the hot solution to cool slowly and let crystals grow
Which of the following is the example of crystallization process?
A. Purification of alum
B. None of the given answers
C. Separation of gases from air
D. Purification of sea water
Purification of alum
A constant boiling mixture of two in a solution is called a/an _______
A. azeotrope
B. Ideal
C. non-ideal solution
D. eutectic mixture
azeotrope
A compound Is known to decompose at its boiling point. Which of the following can be to purity this
substance?
A. Steam distillation
B. Fractional distillation
C. Liquid-liquid extraction
D. Vacuum distillation
Steam distillation
Which is the INCORRECT statement among the following?
A. An impure sample of the substance has a different melting point.
B. Two different pure substances have the same melting points.
C. Melting point serves as the criterion of purity of a solid substance.
D. Every pure crystalline substance has a characteristic and unique melting point.
Two different pure substances have the same melting points.
The boiling point of a liquid is the temperature at which the vapor pressure is ______
A. lesser than internal pressure
B. equal to internal pressure
C. equal to external pressure
D. greater than internal pressure
equal to external pressure
(usually atmospheric pressure pressure)
Which of the following statements is correct?
A. Solid reactants can be weighed directly in the weighing pan of the analytical balance
B. Weight of liquids is approximately equal to its density.
C. Solid reactants can be transferred to a reaction flask by using a metal spatula.
D. Volatile liquids can be weighed by getting the mass of the empty vial with cap first.
Volatile liquids can be weighed by getting the mass of the empty vial with cap first.
A reaction mixture needs to be cooled to -77•C after refluxing. What Is the best method to be used?
A. Place the reaction vessel in an ice bath.
B. Place the reaction vessel in the freezer.
C. Place the reaction vessel in a salt and crushed ice mixture.
D. Place tie reaction mixture in a dry ice-acetone mixture.
Place tie reaction mixture in a dry ice-acetone mixture.
• Ice bath: 0°C (maximum) • Freezer: -20°C • Salt and crushed ice mixture: -20°C
Which of reactions will consume the most oxygen?
A. complete combustion one mole of octane
B. complete combustion of one mole of 2,3-dimethylhexane
C. complete combustion of one mole of 2,3,4-trimethylpentane
D. All the given compounds win consume the same amount of oxygen.
All the given compounds win consume the same amount of oxygen.
(Determine the molecular formula of each compound and compare)
Which of the following techniques can be used to heat a reaction to 200•C?
A. Use a Bunsen burner to heat the reaction vessel.
B. use a heating mantle with stirring.
C. Place the reaction vessel in a sand bath with stirring.
D. Place the reaction vessel in a water bath with stirring.
Place the reaction vessel in a sand bath with stirring.
Which alkyl halide will most likely undergo SN2 mechanism?
A. 2-bromobutane
B. bromomethane
C. 2-bromo-2-methylpropane
D. 1-bromobutane
bromomethane
- tertiary & secondary (SN1)
- primary (SN2)
less carbon = less hindrance
Aldehydes and ketones generally react by ______
A. nucleophilic substitution
B. nucleophilic addition
C. electrophile addition
D. electrophile substitution
nucleophilic addition
AICl3 is a catalyst used in the alkylation of aromatic compounds. It is a
A. a Lewis acid
B. a Lowry-Bronsted acid
C. an Arrhenius acid
D. a Lewis base
a Lewis acid
The reaction rate is defined as the rate at concentration of the reactants ______ time or the rate at which the concentration of products _______ with time
A. decrease, decrease
B. Increase, Increase
C. decrease, Increase
D. Increase. decrease
decrease, Increase
Hydrogenation of an alkene yields _______
A. alcohol
B. aldehyde
C. alkane
D. alkyne
C. alkane
Which of following Is produced when hydrogen is reacted with 2-butanone?
A. tertiary
B. aldehyde
C. primary alcohol
D. secondary alcohol
secondary alcohol
secondary alcohol –> ketone
What of the following reactions are favored by polar aprotic solvent?
A. Both SN1 and SN2 reactions
B. SN1 reactions
C. None of the given choices
D. SN2 reactions
SN2 reactions
Quantitative analysis of compounds can be done using
A. Ion exchange chromatography
B. Liquid chromatography
C. Gas chromatography
D. Thin layer chromatography
Gas chromatography
A mobile phase can be classified as
I. Solid
Il. Liquid
Ill. Gas
A. Il only
B. Ill
C. Il and Ill only
D. I only
Il and Ill only
The ion exchange resin with a functional group of HSO3- exchanges ions with _____
A. Small cations and anions
B. Cations
C. Large cations and anions
D. Anions
Cations
In thin layer chromatography, the solvent or mobile phase contained in a closed chamber is a mixture of
A. a liquid and a gas
B. liquid
C. solids
D. gases
liquid
. The chromaplate or thin layer chromatography plate is made up of
A. Wood
B. Fibro
C. Metal
D. Glass
Glass
Affinity chromatography Is used for the analysis and isolation of ______
A. All of the given answer
B. Insoluble starch substances
C. Enzyme tyrosinase
D. Antibodies bound with a covalently-attached antigen on cellulose column
All of the given answer
Retardation the ratio of
A. Distance moved by solvent from base line to distance moved by the substance from base line
B. Distance moved by substance from base line to distance moved by the solvent from base line
C. Distance moved by solvent from top fine to distance moved by the substance from top line
D. Distance moved by substance from top line to distance moved by the solvent from top line
Distance moved by substance from base line to distance moved by the solvent from base line
substance –> solvent
Gas-solid chromatography is ______ chromatography as basic principle Involved.
A. Absorption
B. Adsorption
C. Ion-exchange
D. Exclusion
Adsorption
In chromatography, the relative solubility of solute in both the phases determines the _____
A. Rate of disappearance of solute
B. Rate of movement of solvent
C. Rate of disappearance of solvent
D. Rate of movement of solute
Rate of movement of solute
Which of the following chromatographic methods is most suitable for the analysis of high molecular weight compounds that are soluble in non-polar solvents?
A. gas- liquid
B. gel filtration
C. ion-exchange
D. gel permeation
gel permeation
“HIGH MOLECULAR WEIGHT” = SIZE exclusion
gas-liquid: for low molecular weight volatile compounds
gel filtration: more commonly used for biological macromolecules
In thin layer chromatography, the relative adsorption of components of the mixture is expressed in
terms of its _______
A. Retardation factor
B. Solubility factor
C. Acceleration factor
D. Both acceleration end retardation factor
Retardation factor
Column chromatography is based on the principle of
A. Ion-exchange
B. Differential adsorption
C. Absorption
D. Exclusion principle
Differential adsorption
The components of the in-column chromatography are eluted in order of
A. Increasing polarity end decreasing distribution ratio
B. Decreasing polarity and increasing distribution ratio
C. Increasing polarity and Increasing distribution ratio
D. Decreasing polarity and decreasing distribution ratio
Increasing polarity and Increasing distribution ratio
Benzene has a smaller distribution ratio, D, In squalene than cyclohexane. squalene is an aliphatic type
of hydrocarbon. What is the order of elution of the two compounds from the GC column?
A. Benzene will be eluted first
B. Cyclohexane will be eluted first.
C. The order of elution cannot be determined.
D. The two peaks will overlap.
Benzene will be eluted first
The elution power of a solvent is determined by
A. Its overall polarity
B. The polarity of the stationary phase
C. All of the given answers
D. The nature of the sample components
All of the given answers
What the wavelength range for UV spectrum of light?
A. 400 nm - 700 nm
B. 10 nm to 400 nm
C. 700 nm to 1 mm
D. 0.01 nm to 10 nm
10 nm to 400 nm
Which is the correct statement from the following?
A. Molecular spectra is more complicated than atomic spectra
B. Molecular spectra arises from the transition of an electron between molecular energy levels
C. In molecular transitions. electronic, rotational and vibration transitions occurs
D. All of the given choices
All of the given choices
Alcohol and ether are often used as solvents. What Is the disadvantage of using these to dissolve
analytes for spectroscopic analysis in the UV-visible region?
A. They react with the analyte given the energy at this region.
B. Their solvents prevent the analyte from absorbing light.
C. They also absorb light at the UV-visible region.
D. They interfere in the transition of the electrons of the analyte
They interfere in the transition of the electrons of the analyte
longest wavelength max in its UV Spectrum
- Conjugated: more conjugated double bonds = longer wavelength
- electron donating group: -OH, -OCH?, and -NH? can increase wavelength
Which of the following is a NOT a characteristic of chromophores?
A. May contain extensive conjugated double bonds
B. Contains unsaturated functional group
C. Added to ions that do not strongly absorb light in the UV-visible region
D. Absorbs strongly at 800 nm
Added to ions that do not strongly absorb light in the UV-visible region
Which of the following Is an application of molecular spectroscopy?
A. All of the given answers
B. Basis of understanding of colors
C. Structural investigation
D. Study of energetically excited reaction products
All of the given answers
Formula of C7H14O exhibits an IR peak at 1715 cm-1. The compound may be a/an ____
A. ketone
B. ether
C. ester
D. alcohol
ketone
The IR peak at 1715 cm?¹ indicates a carbonyl group.
- At which region can be found the peaks due to N — H, C — H and O — H stretching and bending
motions?
A. 2500 to 2000 cm-1
B. 1500 to 1000 cm-1
C. 4000 to 2500 cm-1
D. 2000 to 1500 cm-1
4000 to 2500 cm-1
Hazardous wastes by defining may be all of the following EXCEPT ______
A. Explosive
B. Toxic
C. Corrosive
D. Reactive
Explosive
Which treatment method is NOT typically used to remove organic compounds?
A. Thermal
B. Biological
C. Physical
D. Chemical
Thermal
The following are requirements for hazardous waste storage EXCEPT
A. The floors should be impermeable liquids and resistant to attack by chemicals.
B. Drums should be preferably stored upright or pallets and stacked no more than four drums
C. The facility should be enclosed but ventilated.
D. The facility should be properly secured and can be easily accessed by anyone.
The facility should be properly secured and can be easily accessed by anyone.
. Waste solvents which are halogenated should be placed in separate containers from non-halogenated
waste solvents because ______.
A. Non-halogenated waste solvents are more toxic.
B. They are not compatible with each other.
C. They will react with each other.
D. The cost to properly dispose halogenated waste solvents is higher
The cost to properly dispose halogenated waste solvents is higher
All of the following about hazardous waste containers are true, EXCEPT for the following
A. Containers must be closed except when removing or adding waste.
B. Any type of container, Including food containers. can be used to contain hazardous waste.
C. Contents must be compatible with the type of waste containers.
D. Containers must be clean on the outside.
Any type of container, Including food containers. can be used to contain hazardous waste.
Segregation of waste organic solvents is very important because _______
A The costs for disposal of waste solvents differ.
B. Some waste solvents can still be recycled.
C. Waste solvents differ in proper treatment.
D: All of the given answers
All of the given answers
Which method is considered an unacceptable means of disposing waste?
A. All methods given are unacceptable
B. Pouring down the sink
C. Placing in the regular trash
D. Pouring down the drainage canal
All methods given are unacceptable
If you discover that a hazardous waste container has a minor leak. what should you do?
A. Patch the leaking hazardous waste container.
B. Place the leaking container on to a secondary container so that the waste will be property collected until
It is removed from the laboratory.
C. Immediately transfer the hazardous waste to another empty container in good condition.
D. Immediately notify the Pollution Control Officer so that an environmental report may be filed with the
regulatory agency.
Immediately transfer the hazardous waste to another empty container in good condition.
How is clean, unbroken or broken glass waste to be disposed of?
A. Into a cardboard box lined with a black bag and taped. For small quantities of broken glass. put into sharps container
B. Into containers lined with black bags
C. Into containers lined with yellow bags.
D. Into containers lined with clear bags
A. Into a cardboard box lined with a black bag and taped. For small quantities of broken glass. put into sharps container
. When a chemical splashes In the eye, rinse for ______
A. 10 seconds
B. 30 seconds
C. 5 minutes
D. 15 minutes
15 minutes
Which is the correct procedure for mixing acid and water?
A. Pour acid into water
B. Pour them at the same time
C. Pour water into acid
D. Let the supervisor pour them
Pour acid into water
Which of the following is an acceptable practice when working in a chemical laboratory?
A. Wearing a laboratory coat and safety goggles while performing the analysis
B. Wearing sandals or open-toed shoes
C. Eating and drinking inside the chemical laboratory
D. Wearing gloves to touch door handles, elevator buttons, etc.
Wearing a laboratory coat and safety goggles while performing the analysis
Which of the following pair is not correct about NFPA diamond chemical label hazard warning?
A. Blue: 0 highly toxic
B. Blue: health
C. Red: flammability
D. Red: 0 non-flammable
Blue: 0 highly toxic
[Blue: “0” means no hazard, not “highly toxic]
. Flammable liquids burn only when their vapor is mixed with air in the appropriate concentration. When
handling flammable liquids, you should _______
A avoid nearby sources of ignition
B. use adequately ventilated work areas
C. keep containers closed except during transfer of Contents
D. minimize the creation of flammable vapors
minimize the creation of flammable vapors
Organic peroxides are particularly dangerous when ________
A. concentrated
B. all of the above
C. when ethyl ether or tetrahydrofuran is left open to the air md allowed to evaporate
D. heated
all of the above
