AC-2019 Flashcards
What do you call a combination of two or more materials which retain their individual properties and can be separated by physical means.
A. solvents
B. reactions
C. mixtures
D. solutions
mixtures
A polar solute usually dissolves in a polar solvent and a nonpolar solute usually dissolves in a nonpolar solvent. This Is
A Hund’s rule
B. Henrys law
C. the solubility rule
D. the “Iike dissolves like’ rule
the “Iike dissolves like’ rule
- What is the molarity of a solution containing 72.9 grams of HCI in enough water to make 500 mL of solution?
A. 2.0 m/L
B. 4.05 g/L
C. 5.0 m/L
D. 4.05 m/L
4.05 m/L
A solution has 3x10-4 copper 2+ content. How much is the copper 2+ content in ppm?
A. 3 ppm
B. 38 ppm
C. 9 ppm
D. 19 ppm
19 ppm
Solutions of electrolytes and metals are
A. Insulators
B. Polar
C. Negative
D. Conductors
Conductors
A statement that sums up what you learned from an experiment and states if the hypothesis Is proven or disproven is called
A. procedure
B. control group
C. hypothesis
D. conclusion
conclusion
A prediction or a possible explanation to the question or problem which can be tested in an experiment is called
A. hypothesis
B. procedure
C. graph
D. data
hypothesis
The number 2.34x10-7 is the scientific notation for
A. 234000
B. 23400
C. 23400000
D. 2340000
C. 23400000
Express the number 0.051065 to four significant figures
A. 0.051
B. 0.051
C. 0.05106
D. 0.0511
0.05106
What is the chemical formula of diphosphorus monobromide?
A. PBr2
B. PBr
C. P2Br2
D. P2Br
P2Br
Which of the following Is a chemical reaction?
A. an air conditioner cooling the air
B. none of these choices
C. bleaching your clothes
D. melting of ice
bleaching your clothes
The volume of a liquid is 20.5 mL. Which of the following sets of measurement represents the value with good accuracy?
A. 19.2 mL, 19.3 mL, 18.8 mL, 18.6 mL
B. 18.9 mL, 19.0 mL, 19.2 mL, 18.8 mL
C. 18.6 mL, 17.8 mL, 19.6 mL, 17.2 mL
D. 20.2 mL, 20.5 mL, 20.3 mL, 20.1 mL
20.2 mL, 20.5 mL, 20.3 mL, 20.1 mL
Noble gases are inert because they have completed outer electron shells. Which of these elements isn’t
a noble gas?
A. Chlorine
B. Krypton
C. Helium
D. Argon
Chlorine
What is the most common Isotope of hydrogen?
A. Hydrogen only has one isotope
B. Deuterium
C. Tritum
D. Protium
Protium
As you move from top to bottom down the periodic table
A. change in atomic radius cannot be predicted
B. ionization energy increases
C. electronegativity decreases
D. atomic radius decreases
electronegativity decreases
- What do you call an atom that has more protons than electrons?
A. an anion
B. none of the choices
C. a molecule
D. an isotope
none of the choices (these are cations)
As you move from left to right across the periodic table
A. atomic radius increases
B. Ionization energy decreases
C. electronegativity decreases
D. atomic radius decreases
atomic radius decreases
Which is NOT an acceptable name for Hg2Cl2?
A. mercury (Il) chloride
B. mercury (I) chloride
C. mercurous chloride
D. dimercury dichloride
mercury (Il) chloride
Under the Lewis concept of acid and bases, an acid is
A. An electron pair donor
B. a proton acceptor
C. a proton donor
D. an electron pair acceptor
an electron pair acceptor
Which of the following is NOT an acid?
A. milk of magnesia
B. apple juice
C. milk
D. gastric Juice
milk of magnesia
When NH4Cl hydrolyzes, the resulting solution is
A. acidic
B. basic
C. neutral
D. none of the choices
acidic
Aqua regia, the reagent that can be used to dissolve gold, lg a 3:1 mixture of which acids?
A. hydrochloric and nitric acids
B. hydrofluoric and nitric acids
C. hydrochloric and sulfuric acids
D. perchloric and sulfuric acids
hydrochloric and nitric acids
Which Of the following conjugate acid/base pairs should be used to prepare a buffer with pH near 7.15?
A. Formic acid I sodium formate (pKa — 3.74)
B. Sodium dihydrogen phosphate/ sodium hydrogen phosphate (pKa2 = 7.20)
C. Succinic acid/sodium succinate (pKa = 5.64)
D. Glycylglycine I sodium glycylglycate (pKa = 8.35)
Sodium dihydrogen phosphate/ sodium hydrogen phosphate (pKa2 = 7.20)
What is the gas which behaves the most like an ideal gas?
A. oxygen
B. nitrogen
C. helium
D. hydrogen
helium
What happens to the volume of a fully inflated balloon when it is taken outside on a cold day?
A. its volume decreases
B. its volume increases
C. it remains the same
D. its volume becomes equal to zero
its volume decreases
(Charles’s Law, the volume of a gas is directly proportional to its temperature)
What Is the molar mass or an unknown gas if 1.60 grams of that gas occupies a volume of 2.24 L at STP?
A. 35.8 g/mol
B. 160 g/mol
C. 16.0 g/mol
D. 81.0 g/mol
16.0 g/mol
When chromium changes from an oxidation state of +3 to that of +6, the Cr3+ must:
A. gain 6 electrons
B. lose 6 electrons
C. lose 3 electrons
D. gain 3 electrons
lose 3 electrons
In an electrolytic cell oxidation occurs
A. at the anode
B. between the cathode and the anode
C: at either the cathode or the anode
D. at the cathode
at the anode
(Oxidation - anode
Reduction - cathode
For this reaction Mg + H2O –> MgO + H2 which is FALSE
A. H is the oxidizing agent
B. Mg lost electrons
C. Mg is the oxidizing agent
D. H gained electrons
Mg is the oxidizing agent
Which procedure is recommended for reading the level of an aqueous solution in a buret or graduated cylinder?
A. Keep the eye level with the top of the meniscus and record that reading
B. Read both the bottom and top of the meniscus and average those readings
C. Keep the eye level with the bottom of the meniscus and record that reading
D. Look down at the meniscus at an angle to obtain the average reading directly
Keep the eye level with the bottom of the meniscus and record that reading
What Is the main ISO Standard used by testing and calibration laboratories to gain accreditation and formal of their competence to carry out tests and/or calibrations, including sampling?
A. ISO/IEC 17025
B. EURACHEM
C. AOAC
D. ISO 9000:2000
ISO/IEC 17025
This detects contamination from reagents, sample handling and the entire measurement process.
A. matched-matrix blank
B. method blank
C. solvent blank
D. calibration blank
method blank
There is a definite correlation between orderliness and level of safety in the laboratory. In addition, a disorderly laboratory can hinder or endanger emergency response personnel. Which or the following housekeeping rules should NOT be adhered to?
A. never obstruct access to exits and emergency equipment
B. properly label and store all chemicals
C. store chemical containers on the floor
D. clean work areas, including floors, regularly
store chemical containers on the floor
In order to ensure an accurate weighing when using the balances, one should
A. leave the object on the balance for several minutes to ensure a stable reading
B. not lean on the balance bench, close the draft doors on the balance and zero the balance prior to weighing
C. turn the balance off to clear any previous weighing from its memory
D. weigh the object several times on different balances and take the average of these weighing
not lean on the balance bench, close the draft doors on the balance and zero the balance prior to weighing
Which of the following is NOT part of the technique for pouring in a laboratory?
A Connect the pouring spout and receiving container using a stirring rod
B. Pour fast enough to avoid spills
C. pour and allow the liquid to ran along the stirring rod
D. Hold containers at arm’s length with elbows slightly bent
Pour fast enough to avoid spills
The method that is widely used for the determination of the protein content of meat and animal food is the
A. Kjeldahl method
B. Mohr method
C. McBride method
D. Liebig meth0d
Kjeldahl method
An analytical chemist needs to transfer his/her precipitant from the beaker to the filter paper. Which of the following would be the best procedure to adopt in order to ensure a quantitative transfer of the predicate?
A. none of the choices.
B. Most of the liquid above the ppt is decanted then bulk of ppt Is transferred to filter paper through a stirring rod, the beaker is washed with big volumes of wash solution.
C. Most of the liquid above the ppt is decanted first, bulk of the ppt is transferred through a stirring rod and, wash the beaker several times with small volumes of wash solution.
D. Solution is shaken, then immediately filtered; beaker Is washed with relatively big volumes of wash solution.
Most of the liquid above the ppt is decanted first, bulk of the ppt is transferred through a stirring rod and, wash the beaker several times with small volumes of wash solution.
A water sample Is collected for analysis of Oil and grease. The analysis will not be done immediately. The sample should NOT be
A. collected in plastic bottle
B. preserved with sulfuric acid
C. refrigerated til analyzed
D. collected in all glass bottle
collected in plastic bottle
When two materials that have different densities, like oil and water encounter one another, they will
.
A. separate according to their densities
B. exchange densities
C. mix uniformly
D. repel one another
separate according to their densities
Conductivity is defined as
A. The ability of a substance to conduct electric current, which is the same as resistivity
B. The ability of a substance to repel electric current
C. The ability of a substance to conduct variable resistance
D. The ability of a substance to conduct electric current, which Is the reciprocal of resistivity
The ability of a substance to conduct electric current, which Is the reciprocal of resistivity
Even though all solid states of other materials are denser than the liquid states of materials, what unique property of water?
A. It is clear
B. It Is tasteless
C. Solid water (ice) is less dense than liquid water (ice floats in water)
D. It can freeze
Solid water (ice) is less dense than liquid water (ice floats in water)
The following statements are true about electrical conductivity EXCEPT
A. a measure of a solutions capacity to conduct electricity
B. a measure of the total dissolved solids in a solution
C. increasing temperature has no effect on its value
D is directly affected by temperature
increasing temperature has no effect on its value
The following statements are true about pH EXCEPT
A. The negative logarithm of hydrogen ions content in a solution
B. a measure of the acidity or alkalinity of a solution
C. a measure of the amount or hydrogen ions in solution
D. does not change when there are changes in temperature
does not change when there are changes in temperature
In maintenance and storage of pH meters. which of the following procedure shall NOT be done?
A. Mild soap solution may be used in general cleaning of the electrodes
B. To keep the electrode bulb moist during storage, store the electrode in distilled water.
C. Blot electrode dry after rinsing the pH electrodes.
D. Rinse pH electrodes in between measurements.
To keep the electrode bulb moist during storage, store the electrode in distilled water.
In operating a UV-Vis spectrophotometer, the following shall be done. EXCEPT for
A. Before turning on the power, check if the sample holder does not contain anything.
B. After turning on, allow the spectrophotometer to initialize and stabilize according to its user manual.
C. If there are any spillage that gets onto the instrument, immediately wipe it away.
D. Keep the sample compartment open during measurement.
Keep the sample compartment open during measurement.
In using fume hoods. the following shall be done, EXCEPT for
A. Items contaminated with odorous or hazardous materials should be removed from the hood only after decontamination or if placed in a closed outer container to avoid releasing contaminants into the laboratory air.
B. The hood be kept closed except during apparatus set-up or when working within the hood
C. The hood may be used as e permanent storage area for volatile chemicals when an appropriate storage cabinet is not available.
D. Ensure the exhaust operating before using the hood.
The hood may be used as e permanent storage area for volatile chemicals when an appropriate storage cabinet is not available.
In purifying a material by crystallization choose the solvent according to the following EXCEPT
A. solubility
B. vapor pressure
C. reactivity
D. polarity
vapor pressure
Vapor pressure typically becomes more relevant in processes like distillation rather than crystallization.
The dynamic range in analytical measurement refers to the range where
A. the instrument reading is constant
B. the detection limit lies
C. the sensitivity of the instrument is highest
D. the instrument reading is linearly related to the input value
the detection limit lies
What is the law that states the linear relationship between absorbance and concentration of an absorbing species?
A. Boyles Law
B. Beer-Lambert’s Law
C. Charles Law
D. Avogadro’s Law
Beer-Lambert’s Law
A lab analyst dissolved 4.021 g of NaOH in water and made up the solution to 1 litre with water. He then pipetted 10.00 mL of this solution into a flask and titrated it with 0.050 M HCI solution from a burette. A volume of 20.32 mL of acid had been used at the endpoint. Examining this result, the lab supervisor could deduce that
A. the NaOH absorbed H2O from the air after its mass was measured
B. the burette was rinsed with water instead of HCI
C. the analysis is as accurate as can be expected using this apparatus
D. the pipette was rinsed with water instead of NaOH
the burette was rinsed with water instead of HCI
In which of the following titrations does pH = 7.0 occur at the equivalence point?
I. Strong acid/strong base
ll. Weak acid/strong base
Ill. Strong acid/Weak base
A. Il and Ill only
B. Ill only
C. I only
D. Il only
I only
The following are good sampling practices EXCEPT
A. Collect the sample in a container made of material that will chemically react with the sample.
B. Sample frequently enough to allow for the Identification Of process cycles.
C. Take several increments and composite them to tom the sample.
D. If possible, mix the material before getting the sample.
Collect the sample in a container made of material that will chemically react with the sample.
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. aqueous
B. denser
C. miscible
D. nonaqueous
aqueous
The process in which the sample is heated to the boiling point of the solvent and volatile analytes are concentrated in the vapor phase, condensed and collected.
A. distillation
B. liquid-liquid extraction
C. evaporation
D. oven drying
distillation
Glass container is NOT suitable for
A. oil and grease determination
B microbiological analyses
C. all of the choices
D. inorganic trace analyses
inorganic trace analyses
The maximum holding time for acid preserved samples that will be subjected to determination of metals is
A. 48 hours
B. 3 months
C. 6 months
D. 1 week
6 months
Quantitative chemical analysis of weighing a sample, usually of a separated and dried precipitate is called
A. Gravimetric analysis
B Elemental analysis
C. Volumetric analysis
D. Titrimetric analysis
Gravimetric analysis
What is the light source used In the visible range to 340-1000 nm?
A, nerst blower
B. tungsten
C. deuterium
D. Incandescent
tungsten
Minimum concentration of a substance that can be measured and reported with confidence at the analyte concentration is greater than zero refers to
A Lower Warning Limit
B. Method Detection Limit
C. Control Limit
D. Limit of Quantitation
Method Detection Limit
Which of the following instruments uses a cuvette?
A. Gas Chromatograph
B. U-Vis Spectrophotometer
C. pH Meter
D. Flame-MS
U-Vis Spectrophotometer
The most appropriate technique to determine levels or the Pb2+ ion in blood is
A. atomic absorption spectroscopy
B. mass spectrometry
C. infrared spectroscopy
D. high-performance liquid chromatography
atomic absorption spectroscopy (AAS)
Analytical methods or instruments’ performance aim for
A. Low signal-to-noise ratio
B. High variability
C. Low dynamic range
D. High signal-to-noise ratio
High signal-to-noise ratio
A graphical representation of measuring signal as a function of quantity of analyte is
A. Absorbance Chart
B. Calibration curve
C. Quality Control Chart
D. none of the choices
Calibration curve
For the reaction,
Fe3+(aq) + SCN-(aq) –> FeSCN2+(aq)
The equilibrium constant for this reaction can best be determined by means of
A. Ion-exchange
B. Conductance
C. Spectrophotometry
D. Chromatography
Spectrophotometry
A food scientist has a sample of a plant oil and wants to determine if the oil contains saturated or unsaturated fatty adds. Which of the following techniques would most useful for this purpose?
A. mass spectroscopy
B. ultraviolet spectroscopy
C. infrared spectroscopy
D. visible spectroscopy
infrared spectroscopy
What is a graph showing the detectors response as a function of elution: band’s shapes, position, resolution?
A. monitor display
B. chromatogram
C. quality control chart
D. calibration curve
chromatogram
A stable light source in AAS analysis, which is necessary to emit the sharp characteristic spectrum of the element to be determined is called
A. Tungsten lamp
B. hollow cathode lamp
C. deuterium lamp
D. Nerst blower
hollow cathode lamp
It is a hazardous waste characteristics 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.
A. Reactivity
B. Corrosivity
C. Toxicity
D. Ignitability
Toxicity
The following acids and acid mixtures can be collected and placed in glass containers EXCEPT for
A Sulfuric acid
B. Hydrofluoric acid
C. Aqua regia
D. Hydrochloric acid
Hydrofluoric acid
When working with concentrated acids except hydrofluoric acid, which of the following statements are TRUE?
l. gloves covering the whole arm or Nitrile gloves should be worn.
ll. Half- or full-faced masks with gas- and/or vapor removing respirators should be worn.
Ill. Wearing safety boots or foot covering is optional as long as tie person is working under the hood.
IV. Wearing of apron is optional as long as laboratory gown is worn.
A. I & II
B. II & III
C. all of the choices
D. I & IV
I & II
The fire triangle consists of which of the following?
A. Oxygen, Heat, Material
B. Air, Heat. Fire
C. Air, Fuel, Spark
D. Oxygen. Heat, Fuel
Oxygen. Heat, Fuel
In order to property maintain chemical laboratory equipment one should perform the following EXCEPT
A. place the equipment in hot humid location
B. regular calibration of equipment
C. regular Inspection of operational components
D. thorough cleaning with the proper materials
place the equipment in hot humid location
Which Is TRUE about laboratory hoods?
A. all of the choices
B. Provides further protection by diluting low of flammable gases below explosion limits.
C. It protect you from being exposed in chemical fume.
D. Must always be on
all of the choices
What is the type of chemical that can cause an allergic reaction in the airways following inhalation of chemical
A. Corrosive
B. Respiratory Sensitizer
C. oxidizer
D. Carcinogen
Respiratory Sensitizer
Ammonia solution can be stored with the following chemicals EXCEPT for
A. cyclohexane solution
B. acetic acid solution
C. 2-propanol solution
D. sodium hydroxide solution
acetic acid solution
Which of the following Can Cause ERRORS during the sample preparation stage?
l. Loss of sample during weighing or dissolution
Il. Contamination by impurities in reagents and in the environment
Ill. Changes in mass due to varying humidity and temperature
IV. Obtaining inhomogeneous sample from the bulk
A. l and Il only
B. l, Ill. and IV
C. l, Il, and Ill
D. I, II, Ill, and IV
I, II, Ill, and IV
What will you perform to know that Atomic absorption spectrometer continues to work property?
A. Calibration check
B. Blank
C. QC sample recoveries
D. Standard addition
Calibration check
Consider that you are working with Vitamin C table production, to which standard’s should your quality management should subscribe?
A. GMP
B. HACCP
C. ISO 9001:2008
D. All of the choices
All of the choices
The test that decides whether a datum from a given set could be rejected or NOT IS
A. T-test
B. Z-test
C. Q-test
D. F-test
Q-test
Saying that the concentration of Total cyanide (CN-) In drinking water is 0.05 mg/L. which is below the maximum allowable level of 0.07 mg/L as per DOH DAO No. 20070012 when it is actually that limit is above that limit is .
A. accurate
B. false negative
C. precise
D. false positive
false positive
