EVALUATION EXAM 1

Question 1

How many significant figures are in the value of the universal gas constant R = 0.0821 L·atm/mol·K?
A. 3  B. 4  C. 5  D. Infinite

Answer 1

D. Infinite

Question 2

How many significant figures should be reported in the final answer to the calculation below, assuming all given values are experimentally determined?
12.501 x 3.52 ÷ 0.0042
A. 2  B. 3  C. 4  D. 5

Answer 2

A. 2

Question 3

A scientist records a temperature of 95°F. What is this temperature in Kelvin?
A. 273.15 K  
B. 308.15 K  
C. 335.15 K  
D. 368.15 K

Answer 3

B. 308.15 K 

Question 4

Which of the following pairs consists of intensive properties?
A. Heat capacity, molar heat capacity
B. Cell potential, free energy
C. Density, volume
D. Molarity, viscosity

Answer 4

D. Molarity, viscosity

Question 5

Which of the following is not a compound?
A. Marble  
B. Quicklime  
C. Ozone  
D. Common salt

Answer 5

C. Ozone 

Question 6

Which of the following statements is not correct?
A. Atoms are made up of electrons, protons, and neutrons.
B. All atoms of a given element contain the same number of neutrons.
C. The atomic number of an element indicates the number of protons in its nucleus.
D. Chemical combinations of atoms are called compounds.

Answer 6

B. All atoms of a given element contain the same number of neutrons.

Question 7

Brass is an alloy of
A. Al and Cu  
B. Pb and Cu  
C. Cu and Zn  
D. Cu and Sn

Answer 7

C. Cu and Zn

Question 8

Which of the following is not a chemical change?
A. Burning of magnesium  
B. Electrolysis of water
C. Rusting of iron  
D. Dissolving table salt in water

Answer 8

D. Dissolving table salt in water

Question 9

A cylinder containing a gas is compressed to half its original volume. What will happen to its pressure at constant temperature?
A. doubled  
B. halved  
C. no effect  
D. cannot be determined

Answer 9

A. doubled  

Question 10

What is the density of propane (C₃H₈) at 25°C and 740 mm Hg?
A. 0.509 g/L  
B. 0.570 g/L  
C. 1.75 g/L  
D. 1.96 g/L

Answer 10

C. 1.75 g/L 

Question 10

A 0.239 g sample of an unknown gas is placed in a 100.0 mL flask. At a temperature of 14°C and a pressure of 600 mmHg, what is the identity of the gas?
A. Chlorine  
B. Nitrogen  
C. Krypton  
D. Xenon

Answer 10

A. Chlorine  

Question 11

Which element is the major component in solar cells?
A. As  B. Ge  C. P  D. Si

Answer 11

D. Si

Question 12

Which family of elements has solid, liquid and gaseous members at 25°C and 1 atm?
A. Alkali metals (Li to Cs)
B. Pnictogens (N to Bi)
C. Chalcogens (O to Te)
D. Halogens (F to I)

Answer 12

D. Halogens (F to I)

Question 13

What is the correct formula for ammonium hydrogen phosphate?
A. (NH₄)₃PO₄  
B. (NH₄)₂HPO₄  
C. NH₄H₂PO₄  
D. (NH₄)₂PO₄

Answer 13

B. (NH₄)₂HPO₄ 

Question 14

Which of the following species does not have the electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶?
A. K⁺  B. Cl⁻  C. S²⁻  D. Kr

Answer 14

D. Kr

Question 15

Which of the following elements has a greater electron affinity than oxygen?
A. Sulfur  
B. Carbon  
C. Neon  
D. Fluorine

Answer 15

D. Fluorine

Question 16

As one moves from the top to the bottom of a group in the periodic table, which of the following trends is observed?
A. The trend in atomic size cannot be predicted
B. Electronegativity decreases
C. Ionization energy increases
D. Atomic radius decreases

Answer 16

B. Electronegativity decreases

Question 16

What general trend is observed as you move from left to right across a period in the periodic table?
A. Atomic radius increases  
B. Atomic radius decreases
C. Ionization energy decreases  
D. Electronegativity decreases

Answer 16

B. Atomic radius decreases

Question 17

Which statement correctly describes the radii of atoms and their corresponding ions?

A. Cations and anions are both larger than their neutral atoms
B. Cations are smaller than their neutral atoms; anions are larger than their atoms
C. Cations are larger than their atoms; anions are smaller than their atoms
D. Cations and anions are both smaller than their neutral atoms

Answer 17

B. Cations are smaller than their neutral atoms; anions are larger than their atoms

Question 18

What is the process of breaking down a large nucleus into smaller nuclei called?
A. Nuclear fission  
B. Beta particle emission
C. Nuclear fusion  
D. Gamma ray emission

Answer 18

A. Nuclear fission

Question 19

Which of the following correctly describes how temperature generally affects the solubility of a solid solute in water?
A. Solubility decreases as temperature increases.
B. Solubility increases as temperature increases.
C. Temperature has no effect on solubility.
D. Solubility is always highest at 0°C.

Answer 19

B. Solubility increases as temperature increases.

Question 20

How does increasing temperature affect the viscosity of a liquid?
A. The molecules move more slowly, increasing viscosity.
B. Intermolecular forces become stronger, increasing viscosity.
C. Molecules move more freely, decreasing viscosity.
D. The liquid becomes more dense, increasing viscosity.

Answer 20

C. Molecules move more freely, decreasing viscosity.

Question 21

How many grams of potassium dichromate (K₂Cr₂O₇, 294.2 g/mol) are required to prepare 250 mL of a 0.10 M solution?
A. 1.18 g  B. 2.94 g  C. 6.38 g  D. 7.36 g

Answer 21

D. 7.36 g

Question 22

An exact amount of 0.8214 g of KMnO₄ (158 g/mol) was dissolved in water and made up to volume in a 500-mL volumetric flask. A 2.00-mL portion of this solution was transferred to a 1000-mL flask and diluted to volume. Then 10.00 mL of the diluted solution was transferred to a 250-mL flask and diluted to volume. What is the molar concentration of the final solution?
A. 0.104 M  
B. 2.08×10⁻⁵ M  
C. 8.32×10⁻⁷ M  
D. none of the above

Answer 22

C. 8.32×10⁻⁷ M 

Question 23

Under the Brønsted-Lowry concept of acids and bases, a base is a(n): A. Proton donor   B. Proton acceptor C. Electron pair donor   D. Electron pair acceptor

Answer 23

B. Proton acceptor

Question 24

Which of the following statements about pH is not true? A. It is the negative logarithm of the hydrogen ion concentration in a solution. B. It is a measure of the acidity or alkalinity of a solution. C. It is a measure of the amount of hydrogen ions in solution. D. It remains constant regardless of changes in temperature.

Answer 24

D. It remains constant regardless of changes in temperature.

Question 25

When ammonium chloride undergoes ionization, the resulting solution will have a pH: A. <7  B. 7  C. >7  D. 14

Answer 25

A. <7

Question 26

In which of the following titrations does pH = 7.0 occur at the equivalence point? I. Strong acid and strong base II. Weak acid and strong base III. Strong acid and weak base A. I and III  B. II only  C. I only  D. I only

Answer 26

C. I only

Question 27

Which of these conjugate acid–base pairs must be used to prepare a buffer with pH near 7.15? A. formic acid and sodium formate (pKₐ 3.74) B. succinic acid and sodium succinate (pKₐ 5.64) C. glycylglycine and sodium gylcylglycate (pKₐ 8.35) D. sodium dihydrogen phosphate and sodium hydrogen phosphate (pKₐ 7.20)

Answer 27

D. sodium dihydrogen phosphate and sodium hydrogen phosphate (pKₐ 7.20)

Question 28

[INSERT REACTION] What is the percent yield if 0.85 g of acetylsalicylic acid (aspirin) is obtained from the reaction of 1.00 g of salicylic acid with excess acetic anhydride? A. 65%  B. 77%  C.85%  D. 91%

Answer 28

A. 65%

Question 29

Which piece of laboratory apparatus is not used for the purpose listed? Apparatus = Purpose A. Aspirator = Measure height B. Buret = Measure volume C. Calorimeter = Measure thermal energy change D. Desiccator = Store samples in dry conditions

Answer 29

A. Aspirator = Measure height

Question 30

Which of the following should be done before using an analytical balance? A. Clean the balance and remove any sample residue B. Determine the sensitivity of the balance using a calibration weight C. Check the level of the balance by adjusting the air bubble D. All of the above

Answer 30

D. All of the above

Question 31

Which of the following statements is correct? A. Solid reactants can be weighed directly on the pan of an analytical balance B. The weight of a liquid is approximately equal to its density C. Solid reactants can be transferred to a reaction flask using a metal spatula D. Volatile liquids can be weighed by first recording the mass of the capped empty vial

Answer 31

D. Volatile liquids can be weighed by first recording the mass of the capped empty vial

Question 32

Which would be most suitable for measuring 2.7 mL of ethanol for addition to a reaction with acidified dichromate? A. 10-mL graduated cylinder   B. 10-mL volumetric flask C. 10-mL volumetric pipet   D. 10-mL beaker

Answer 32

A. 10-mL graduated cylinder 

Question 33

What is the reading of the buret shown? [INSERT PICTURE] A. 30.20 mL   B. 30.25 mL   C. 30.30 mL   D. 31.75 mL

Answer 33

C. 30.30 mL 

Question 34

When a liquid is delivered from a volumetric pipet a small amount is typically retained in the tip. How should a student proceed in order to deliver the volume of liquid stated on the pipet? A. Leave the small amount in the tip. B. Use a pipet bulb to expel the remaining droplet. C. Shake the pipet to dispense the remaining liquid. D. Draw the liquid above the line to compensate for the liquid that remains in the tip.

Answer 34

A. Leave the small amount in the tip.

Question 35

What is the correct procedure for dispensing liquids using a volumetric pipet? A. Immerse pipet, lift with finger on top, drain to mark, then drain remaining liquid. B. Immerse pipet, lift with finger on top, drain to mark, then gently blowout residual liquid with a pipet bulb. C. Submerge tip, suction with pipet bulb to above mark, cover top with finger, drain to mark, then drain remaining liquid. D. Submerge tip, suction by mouth to mark, then drain contents.

Answer 35

C. Submerge tip, suction with pipet bulb to above mark, cover top with finger, drain to mark, then drain remaining liquid.

Question 36

When equal volumes of the following pairs of liquids are mixed thoroughly and allowed to stand, which pair is most likely to separate into two layers? A. Ethanol and methanol B. Carbon tetrachloride and methanol C. Hexane and pentane D. Carbon tetrachloride and hexane

Answer 36

B. Carbon tetrachloride and methanol

Question 37

Cyclohexane and water can be separated by using a separatory funnel. Which property contributes to this separation? A. Cyclohexane and water are immiscible. B. Cyclohexane has a lower viscosity than water. C. Cyclohexane has a greater molar mass than water. D. Cyclohexane has a greater vapor pressure than water.

Answer 37

A. Cyclohexane and water are immiscible.

Question 38

When selecting a solvent for purifying a material by crystallization, which of the following is not a consideration? A. Solubility B. Vapor pressure C. Reactivity D. Polarity

Answer 38

B. Vapor pressure

Question 39

What is the key step in the 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 letting crystals grow D. Removing soluble impurities by vacuum filtration

Answer 39

C. Allowing the hot solution to cool slowly and letting crystals grow

Question 40

Which of the following factors does not affect the boiling point of a substance? A. Atmospheric pressure B. Altitude C. Nature of intermolecular forces D. Mass of the substance

Answer 40

D. Mass of the substance

Question 41

A round-bottom flask, a condenser, a heat source, and clamps are typically assembled in the lab for which of the following procedures? A. Distillation B. Filtration C. Reflux D. Crystallization

Answer 41

C. Reflux

Question 42

Aqua regia, the reagent that can be used to dissolve gold, is a 3:1 mixture of which acids? A. Hydrochloric and sulfuric acids B. Hydrofluoric and nitric acids C. Hydrochloric and nitric acids D. Perchloric and sulfuric acids

Answer 42

C. Hydrochloric and nitric acids

Question 43

What is the proper way to dispose of a two milliliter sample of hexane after completing experiments with it? A. Return it to the stock bottle B. Place in a waste bottle with compatible organic materials C. Flush it down the drain with large quantities of water D. Pour it on a used absorbent so it can be burned with solid waste

Answer 43

B. Place in a waste bottle with compatible organic materials

Question 44

A student is cleaning a buret in preparation for a titration in which the buret will be filled with 0.100 M NaOH. What should be used for the final rinse of the buret? A. Ethanol B. Distilled water C. 0.100 M HCl D. 0.100 M NaOH

Answer 44

D. 0.100 M NaOH

Question 45

Concentrated hydrochloric acid is 12 M and has a density of 1.18 g/mL. What is the weight percent of concentrated HCl (36.45 g/mol)? A. 5.1 B. 14 C. 37 D. 98

Answer 45

C. 37

Question 46

A standard solution of barium hydroxide is 0.250 M. What volume of 0.200 M nitric acid would be required to neutralize 10.0 mL of the barium hydroxide solution? A. 10.0 mL B. 25.0 mL C. 30.0 mL D. 20.0 mL

Answer 46

B. 25.0 mL

Question 47

A solution is prepared by dissolving 10.00 g of a salt in 90.00 g of water. What additional information is required to calculate the molarity of the solution? I. Molar mass of the salt   II. Density of the solution A. I only B. II only C. Both I and II D. The molarity cannot be determined even with both I and II

Answer 47

C. Both I and II

Question 48

An analyst discovers that the analytical balance used in a test was improperly calibrated. What type of error does this represent? A. Systematic error B. Random error C. Gross error D. Cannot be determined

Answer 48

A. Systematic error

Question 49

An analyst repeatedly weighs a sample on an analytical balance. Each time, the reading varies slightly (0.1221 g, 0.1224 g, 0.1220 g), even though no changes are made to the sample or conditions. What is the most likely cause of this variation? A. Systematic error due to bias in the balance B. Random error due to environmental fluctuations C. Gross error from misrecording the mass D. Calibration error in the balance

Answer 49

B. Random error due to environmental fluctuations

Question 50

While performing a titration to determine the concentration of an acid, a student knocks over the buret stand partway through the experiment. Some of the titrant spills, and the student hastily tries to estimate how much was lost based on memory instead of repeating the experiment. What type of error has occurred? A. Random error due to changes in the titrant B. Systematic error due to incorrect technique C. Gross error due to clumsy behavior and poor lab practice D. Instrumental error due to volume reading

Answer 50

C. Gross error due to clumsy behavior and poor lab practice

Question 51

A chemist is analyzing caffeine in energy drinks by spectrophotometry, using known concentrations of pure caffeine to construct a calibration curve. The method of determining caffeine concentration in unknown samples is being used. A. Standard addition B. Internal standard C. External standard D. Calibration curve

Answer 51

C. External standard

Question 52

Which graph shows instrument’s response plotted against standard solution concentrations? A. Linear range B. Calibration curve C. Dynamic range D. Linear dynamic range

Answer 52

B. Calibration curve

Question 53

In an electrochemical cell, the anode is a strip of magnesium. Which of the following metals is most likely the cathode? A. Zinc B. Copper C. Potassium D. Sodium

Answer 53

B. Copper

Question 54

Which of the following processes does not involve an electrochemical cell? A. Electroplating silver onto a spoon B. Charging a rechargeable battery C. Using a salt bridge to complete a redox circuit D. Heating a solution to speed up a reaction

Answer 54

D. Heating a solution to speed up a reaction

Question 55

What is the main function of the glass membrane in a pH electrode? A. Maintains electrical neutrality in solution B. Generates a potential based on hydroxide ion concentration C. Conducts electricity between reference and sample D. Responds selectively to hydrogen ion concentration

Answer 55

D. Responds selectively to hydrogen ion concentration

Question 56

Carbon monoxide is a common gaseous pollutant emitted from automobile exhaust. Which of the following reagents is used in gas analysis to absorb CO quantitatively? A. Calcium chloride B. Pyrogallol acid C. Copper(I) chloride D. Sodium hydroxide

Answer 56

C. Copper(I) chloride

Question 57

In TLC, the relative adsorption of the components in a mixture is expressed in terms of the: A. Retardation factor B. Solubility factor C. Acceleration factor D. Acceleration and retardation factor

Answer 57

A. Retardation factor

Question 58

The chromatographic or TLC plate is typically made of: A. Wood B. Fibro C. Metal D. Glass

Answer 58

A. Retardation factor

Question 59

In chromatography, the relative solubility of a solute in both the stationary and mobile 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

Answer 59

D. Rate of movement of solute

Question 60

The elution power of a solvent is primarily determined by: A. Its overall polarity B. Polarity of the stationary phase C. Nature of the sample components D. All of the above

Answer 60

D. All of the above

Question 61

In gas chromatography, the components of a sample are eluted in the order of: A. Increasing polarity and decreasing distribution ratio B. Increasing polarity and increasing distribution ratio C. Increasing polarity and increasing distribution ratio D. Decreasing polarity and decreasing distribution ratio

Answer 61

C. Increasing polarity and increasing distribution ratio

Question 62

Which of the following cannot be used as an adsorbent in column chromatography? A. Alumina B. Silica C. Potassium permanganate D. Magnesium oxide

Answer 62

C. Potassium permanganate

Question 63

Benzene has a smaller distribution ratio (D) in squalene than cyclohexane. Squalene is an aliphatic hydrocarbon. Based on this, what is the order of elution of benzene and cyclohexane in GC? Note: D = concentration of sample in stationary phase / concentration in mobile phase. A. Benzene will be eluted first B. Cyclohexane will be eluted first C. Cannot be determined D. The two peaks will overlap

Answer 63

A. Benzene will be eluted first

Question 64

An environmental chemist is analyzing air samples to detect low concentrations of polluted gases. Which of the following techniques would be most appropriate for this type of analysis? A. Paper Chromatography B. Gas–Liquid Chromatography C. Gas–Solid Chromatography D. Thin Layer Chromatography

Answer 64

C. Gas–Solid Chromatography

Question 65

Ion exchange chromatography is used for all of the following applications, except: A. Separation of sugars B. Separation of amino acids C. Separation of rare earth elements D. Separation of trace metal ions

Answer 65

A. Separation of sugars

Question 66

Which of the following is not a typical application of a colorimeter? A. Measuring ink formulations B. Testing cosmetics C. Determining solution concentration D. Identifying chemical composition

Answer 66

D. Identifying chemical composition

Question 67

A hollow cathode tube lamp is necessary in AAS because: A. Atom’s absorption band is narrow B. Cathode lamps cost less to run C. Other lamps don’t give enough light D. Other lamps ionize the sample

Answer 67

A. Atom’s absorption band is narrow

Question 68

Which of the following is an application of molecular spectroscopy? A. All of the given answers B. Understanding the basis of color C. Structural investigation D. Study of excited reaction products

Answer 68

A. All of the given answers

Question 69

Which of the following statements about molecular spectra is correct? A. Molecular spectra are more complex than atomic spectra B. Molecular spectra arise from transitions between molecular energy levels C. Molecular transitions can involve electronic, vibrational, and rotational changes D. All of the given choices

Answer 69

D. All of the given choices

Question 70

Which will be most effective at distinguishing between paired isotopes ⁷⁹Br and ⁸¹Br isotopes? A. Infrared spectroscopy B. Mass spectrometry C. UV-Vis Spectroscopy D. Atomic absorption

Answer 70

B. Mass spectrometry

Question 70

Which of the following is not a characteristic of chromophores? A. They may contain extensive conjugated double bonds. B. They contain unsaturated functional groups. C. They are added to compounds that do not strongly absorb light in the UV-Visible region. D. They absorb strongly at 800 nm.

Answer 70

D. They absorb strongly at 800 nm.

Question 71

What is the typical wavelength range of UV radiation in the electromagnetic spectrum? A. 400 nm to 700 nm B. 100 nm to 400 nm C. 700 nm to 1 mm D. 0.01 nm to 10 nm

Answer 71

B. 100 nm to 400 nm

Question 72

Which is most likely to exhibit a strong IR absorption at 1700 cm⁻¹ due to a C=O stretch? A. Ethanol B. Acetone C. Ethene D. Aniline

Answer 72

B. Acetone