AC-2019 Flashcards by potatochips ~

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

Solutions of electrolytes and metals are

A. Insulators
B. Polar
C. Negative
D. Conductors

Conductors

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

The number 2.34x10-7 is the scientific notation for
A. 234000
B. 23400
C. 23400000
D. 2340000

C. 23400000

How well did you know this?

Not at all

Perfectly

Express the number 0.051065 to four significant figures
A. 0.051
B. 0.051
C. 0.05106
D. 0.0511

0.05106

How well did you know this?

Not at all

Perfectly

What is the chemical formula of diphosphorus monobromide?

A. PBr2
B. PBr
C. P2Br2
D. P2Br

P2Br

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

What is the most common Isotope of hydrogen?
A. Hydrogen only has one isotope
B. Deuterium
C. Tritum
D. Protium

Protium

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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)

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

Which of the following is NOT an acid?
A. milk of magnesia
B. apple juice
C. milk
D. gastric Juice

milk of magnesia

How well did you know this?

Not at all

Perfectly

When NH4Cl hydrolyzes, the resulting solution is

A. acidic
B. basic
C. neutral
D. none of the choices

acidic

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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)

How well did you know this?

Not at all

Perfectly

What is the gas which behaves the most like an ideal gas?

A. oxygen
B. nitrogen
C. helium
D. hydrogen

helium

How well did you know this?

Not at all

Perfectly

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