Chemistry Trivia Questions for Students — page 2

The specific rate constant, k, for a certain first-order reaction is 86 h^-1. What mass of a 0.0500 g sample of starting material will remain after 58 s?

• A0.0125 g
• B0.0500 g
• C0.00625 g
• D0.0250 g

para-dichlorobenzene is used as "mothballs." This compound can also be named

• A2,4-dichlorobenzene
• B1,4-dichlorobenzene
• C1,2-dichlorobenzene
• D1,3-dichlorobenzene

Nitrous acid, HNO2, has a pKa value of 3.3. If a solution of nitrous acid is found to have a pH of 4.2, what can be said about the concentration of the conjugate acid/base pair found in solution?

• A[NO2-] > [HNO2]
• B[HNO2] > [NO2-]
• C[HNO2] > [H2NO2+]
• D[H2NO2+] > [HNO2]

Less than 1/1000 of the mass of any atom is contributed by

• Athe electrons and neutrons
• Bthe electrons and protons
• Cthe protons and neutrons
• Dthe electrons

Which of the following reactions is expected to have the greatest decrease in entropy?

• AC(s) + O2(g) → CO2(g)
• BHCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
• C2 SO2(g) + O2(g) → 2 SO3(g)
• DCH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l)

Which of the following is expected to have the largest bond polarity?

• AC–N
• BP–F
• CC–B
• DS–O

The equilibrium constant of a certain reaction is 2.6 × 10^8 at 25 °C. What is the value of ΔG°?

• A-48.0 kJ/mol
• B-4.03 kJ mol-1
• C20.8 J mol-1
• D4.68 × 10^-3 kJ/mol

Which is the easiest way to burn a silver coin?

• AUse the method in (A), but use an oxyacetylene torch to reach a higher temperature.
• BGrind the silver coin into very small, dust-sized particles, and spray the particles into a Bunsen burner flame.
• CDissolve the silver coin in acid, precipitate the hydroxide, and heat in a Bunsen burner flame to make the oxide.
• DHold the silver coin with crucible tongs, and heat strongly in the flame of a Bunsen burner.

Iron(III) hydroxide has Ksp = 1.6 × 10^-39. What is the molar solubility of this compound?

• A7.4 × 10^-14 mol/L
• B2.0 × 10^-10 M
• C9.4 × 10^-6 mol/L
• D8.8 × 10^-11 M

Chlorine gas reacts most readily with

• Atoluene
• Bethanoic acid
• Cethane
• Dethylene

Magnesium has an atomic radius of 160 pm and a first ionization energy of 737 kJ. Based on periodic trends and the data given above, what are the most probable values for the ionization energy and atomic radius of sodium?

• A186 pm, 898 kJ/mol
• B186 pm, 496 kJ/mol
• C147 pm, 523 kJ/mol
• D135 pm, 523 kJ/mol

The net ionic equation expected when solutions of NH4Br and AgNO3 are mixed together is

• ANH4Br(aq) + NO3-(aq) → NH4NO3(aq) + Br-(aq)
• BNH4+(aq) + Ag+(aq) → Ag(NH4)3+2(aq)
• CAg+(aq) + Br-(aq) → AgBr(s)
• DBr-(aq) + NO3-(aq) → NO3Br(aq)

What is an alpha particle?

• AAnother name for a positron
• BAnother name for a helium nucleus
• CAnother name for a cosmic ray
• DAnother name for an electron

Hund's rule requires that

• Ano two electrons can pair up if there is an empty orbital at the same energy level available
• Bno two electrons with the same spin can occupy an orbital
• Cno two electrons can have the same four quantum numbers
• Dno two electrons can occupy separate orbitals

Atoms of four elements are examined: carbon, nitrogen, neon, and sulfur. Atoms of which element would have the strongest magnetic moment?

• ASulfur
• BNitrogen
• CCarbon
• DNeon

Bromine has a normal boiling point of 59 °C, and iodine boils at 184 °C. The I2 molecule is much larger than Br2 (atomic radii are 114 and 133 pm, respectively). Which is the best reason for the large difference in boiling points?

• AThe mass of iodine is much greater than the mass of bromine.
• BThe intramolecular bonds in I2 are much weaker than those in Br2.
• CThe I2 electron clouds are much more polarizable than the Br2 electron clouds, resulting in much stronger London forces.
• DBromine is a liquid and boils; iodine is a solid and sublimes.

Which of the following is expected to have the highest electronegativity?

• AW
• BFe
• CS
• DAg

How many moles of propane (C3H8) are there in 6.2 g of propane?

• A1.4 × 10^-1 mol
• B14.1 mol
• C7.1 mol
• D71 mol

When will Kp and Kc have the same numerical value?

• AAt absolute zero for all reactions
• BWhen the reaction exhibits no change in pressure at constant volume
• CWhen the concentrations are at standard state
• DWhen the concentrations are all 1.00 molar

The simplest alkene has

• Aat least four sigma bonds
• Bat least two pi bonds
• Ca tetrahedral configuration
• Dcis-trans isomers

A 50.0 mL sample of 0.0025 M HBr is mixed with 50.0 mL of 0.0023 M KOH. What is the pH of the resulting mixture?

• A11
• B5
• C4
• D1

Hydrogen fluoride, HF, is a liquid at 15°C. All other hydrogen halides (represented by HX, where X is any other halogen) are gases at the same temperature. Why?

• AHF is smaller than any other H-X molecule; therefore it exhibits stronger London dispersion forces.
• BThe H-F bond is the most ionic in character compared to all other hydrogen halides.
• CFluorine has a very high electronegativity; therefore the H-F bond is stronger than any other H-X bond.
• DThe dipoles in a HF molecule exhibit a particularly strong attraction force to the dipoles in other HF molecules.

Dissolving one mole of each of the following compounds in water results in solutions with different pH values. Under those conditions, which of the following acids will have the highest percentage ionization?

• AH2S
• BHNO2
• CH3PO4
• DHClO4

Neutral atoms of chlorine are bombarded by high-energy photons, causing the ejection of electrons from the various filled subshells. Electrons originally from which subshell would have the highest velocity after being ejected?

• A1s
• B3d
• C3p
• D2p

What is the molar mass of a monoprotic weak acid that requires 26.3 mL of 0.122 M KOH to neutralize 0.682 gram of the acid?

• A147 g mol-1
• B682 g mol-1
• C212 g mol-1
• D4.70 g mol-1

What is the molarity of a sodium hydroxide solution that requires 42.6 mL of 0.108 M HCl to neutralize 40.0 mL of the base?

• A0.0641 M
• B0.115 M
• C0.400 mol/L
• D1.64 M

During a chemical reaction, NO(g) gets reduced and no nitrogen-containing compound is oxidized. Which of the following is a possible product of this reaction?

• ANO2(g)
• BNO3-(aq)
• CNO2-(aq)
• DN2(g)

The molar heat of vaporization of water is +43.9 kJ. What is the entropy change for the vaporization of water?

• A4.184 J mol-1 K-1
• B118 J mol-1 K-1
• C8.49 J mol-1 K-1
• D2.78 J mol-1 K-1

Carbon has an atomic radius of 77 pm and a first ionization energy of 1086 kJ/mol.

• A40 pm, 995 kJ/mol
• B135 pm, 523 kJ/mol
• C70 pm, 1402 kJ/mol
• D86 pm, 898 kJ/mol

When an ideal gas is allowed to expand isothermally, which one of the following is true?

• Aq = 0
• BE = 0
• Cq = -w
• Dw = 0

An unknown substance is found to have a high melting point. In addition, it is a poor conductor of electricity and does not dissolve in water. The substance most likely contains

• Acovalent network bonding
• Bionic bonding
• Cmetallic bonding
• Dnonpolar covalent bonding

Which of the following salts is expected to produce an alkaline solution when one mole is dissolved in one liter of water?

• ANa2S
• BNaClO4
• CNH4Br
• DCaCl2

A 2.35-gram sample was dissolved in water, and the chloride ions were precipitated by adding silver nitrate (Ag+ + Cl- → AgCl). If 0.435 g of precipitate was obtained, what is the percentage of chlorine in the sample?

• A43.50%
• B4.60%
• C18%
• D10.80%

Consider the Lewis structures for the following molecules: CO2, CO32-, NO2-, and NO3-. Which molecule would have the smallest bond angle between terminal atoms?

• ANO3-
• BNO2-
• CCO32-
• DCO2

To prepare a buffer, all of the following are needed except

• Aa conjugate acid along with its conjugate base
• Ban acid with a pKa close to the desired pH
• Ca buffer capacity sufficient to react with added acid or base
• Dtriple-distilled water

Approximately how many half-lives will it take to reduce 10.0 kg of a radioactive substance to 1.0 microgram of that substance?

• A13
• B8
• C29
• D34

A solution contains a mixture of four different compounds: KCl(aq), Fe(NO3)3(aq), MgSO4(aq), and N2H4(aq). Which of these compounds would be easiest to separate via distillation?

• AKCl(aq)
• BMgSO4 (aq)
• CN2H4(aq)
• DFe(NO3)3(aq)

An ester is made by reacting

• Aan amine and an alcohol
• Ban alcohol and an acid
• Ctwo different alcohols
• Dan acid and a base

In acid solution the bromate ion, BrO3- can react with other substances, resulting in Br2. Balance the half-reaction for bromate ions forming bromine. The balanced half-reaction has

• A6 electrons on the left
• B3 electrons on the left
• C10 electrons on the left
• D6 electrons on the right

0.25 mol of a weak, monoprotic acid is dissolved in 0.25 L of distilled water. The pH was then measured as 4.26. What is the pKa of this weak acid?

• A3.66
• B4.26
• C8.52
• D7.52

Radon is a health hazard because

• Ait is a gas that can be inhaled and then it may decay to a solid that resides in the lungs
• Bit is a gas that enters the body easily and targets the thyroid because it is chemically similar to iodine
• Cit is a gas that enters the body easily and targets bones because it is chemically similar to calcium
• Dit is a gas that is extremely soluble in the bloodstream, and it decays in vital organs

Which of the following lists the electromagnetic spectral regions in order of decreasing wavelength?

• AX-ray, visible, ultraviolet, infrared
• BX-ray, ultraviolet, visible, infrared
• Cinfrared, visible, ultraviolet, X-ray
• Dultraviolet, visible, infrared, X-ray

A sample of solid MgCl2 would be most soluble in which of the following solutions?

• AAlCl3(aq)
• BCBr4(aq)
• CMg(NO3)2(aq)
• DLiOH(aq)

When using the ideal gas law, standard conditions for temperature and pressure are

• A0 °F and 1 atmosphere pressure
• B0 K and 0 torr
• C25 °C and 1 atmosphere pressure
• D0 °C and 760 torr

Substances whose Lewis structures must be drawn with an unpaired electron are called

• Aionic compounds
• Bresonance structures
• Cfree radicals
• Dpolar molecules

Which of the following geometries corresponds to a substance that has five sigma bonds and one nonbonding pair of electrons?

• AOctahedron
• BSquare planar
• CSquare pyramid
• DTetrahedron

What is the ionization constant, Ka, for a weak monoprotic acid if a 0.060 molar solution has a pH of 2.0?

• A2.0 × 10^-1
• B2.0 × 10^-3
• C1.7 × 10^-1
• D5.0 × 10^-3

An ideal solution is a

• Amixture where two solvents can be dissolved in all ratios
• Bmixture that is colorless
• Cmixture where the potential energy of the mixture is the same as that of the individual solvents
• Dmixture that has the same physical properties as the individual solvents

How many milliliters of 0.250 M KOH does it take to neutralize completely 50.0 mL of 0.150 M H3PO4?

• A270 mL
• B30.0 mL
• C90.0 mL
• D27 mL

A sample of oxygen gas at 50 °C is heated, reaching a final temperature of 100 °C. Which statement best describes the behavior of the gas molecules?

• ATheir velocity increases by a factor of four.
• BTheir kinetic energy increases by a factor of less than 2.
• CTheir velocity increases by a factor of two.
• DTheir kinetic energy increases by a factor of 2.