London dispersion forces are caused by<n>A.temporary dipoles created by the position of electrons around the nuclei in a molecule<n>B.the three-dimensional intermolecular bonding present in all covalent substances<n>C.the uneven electron-to-proton ratio found on individual atoms of a molecule<n>D.the electronegativity differences between the different atoms in a molecule[SEP]A
Carbon has an atomic radius of 77 pm and a first ionization energy of 1086 kJ/mol.<n>A.70 pm, 1402 kJ/mol<n>B.86 pm, 898 kJ/mol<n>C.135 pm, 523 kJ/mol<n>D.40 pm, 995 kJ/mol[SEP]A
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<n>A.ionic bonding<n>B.nonpolar covalent bonding<n>C.covalent network bonding<n>D.metallic bonding[SEP]C
The net ionic equation expected when solutions of NH4Br and AgNO3 are mixed together is<n>A.Ag+(aq) + Br-(aq) → AgBr(s)<n>B.NH4+(aq) + Ag+(aq) → Ag(NH4)3+2(aq)<n>C.Br-(aq) + NO3-(aq) → NO3Br(aq)<n>D.NH4Br(aq) + NO3-(aq) → NH4NO3(aq) + Br-(aq)[SEP]A
The symbol for antimony is<n>A.W<n>B.Sb<n>C.Fe<n>D.An[SEP]B
A sealed, rigid container contains three gases: 28.0 g of nitrogen, 40.0 g of argon, and 36.0 g of water vapor. If the total pressure exerted by the gases is 2.0 atm, what is the partial pressure of the nitrogen?<n>A.0.33 atm<n>B.0.40 atm<n>C.0.50 atm<n>D.2.0 atm[SEP]C
Monatomic ions of the representative elements are often<n>A.very soluble<n>B.very electronegative<n>C.isoelectronic with a noble gas<n>D.highly colored[SEP]C
Hund's rule requires that<n>A.no two electrons can have the same four quantum numbers<n>B.no two electrons with the same spin can occupy an orbital<n>C.no two electrons can occupy separate orbitals<n>D.no two electrons can pair up if there is an empty orbital at the same energy level available[SEP]D
All of the following ions have the same electron configuration except<n>A.Rb+<n>B.Se2-<n>C.As5+<n>D.Sr2+[SEP]C
Sulfurous acid is a weak acid, while sulfuric acid is a much stronger acid because<n>A.the O–H bonds in sulfuric acid are much weaker than in sulfurous acid due to the electron withdrawing of the oxygen atoms on sulfuric acid<n>B.sulfuric acid has more oxygen atoms in its formula<n>C.the sulfur in sulfuric acid is more electronegative than the sulfur in sulfurous acid<n>D.sulfuric acid has the hydrogen atoms bound directly to the sulfur atom[SEP]A
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?<n>A.0.0641 M<n>B.1.64 M<n>C.0.115 M<n>D.0.400 mol/L[SEP]C
Which of the following substances has an asymmetrical molecular structure?<n>A.SF4<n>B.PCl5<n>C.BF3<n>D.CO2[SEP]A
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?<n>A.Fluorine has a very high electronegativity; therefore the H-F bond is stronger than any other H-X bond.<n>B.HF is smaller than any other H-X molecule; therefore it exhibits stronger London dispersion forces.<n>C.The dipoles in a HF molecule exhibit a particularly strong attraction force to the dipoles in other HF molecules.<n>D.The H-F bond is the most ionic in character compared to all other hydrogen halides.[SEP]C
The reaction of Br2(g) with Cl2(g) to form BrCl(g) has an equilibrium constant of 15.0 at a certain temperature. If 10.0 grams of BrCl is initially present in a 15.0-liter reaction vessel, what will the concentration of BrCl be at equilibrium?<n>A.3.8 × 10^-3 mol/L<n>B.5.77 × 10^-3 mol/L<n>C.1.97 × 10^-3 M<n>D.9.9 × 10^-4 M[SEP]A
A sample of liquid NH3 is brought to its boiling point. Which of the following occurs during the boiling process?<n>A.The N-H bonds within the NH3 molecules break apart.<n>B.The overall temperature of the solution rises as the NH3 molecules speed up.<n>C.The amount of energy within the system remains constant.<n>D.The hydrogen bonds holding separate NH3 molecules together break apart.[SEP]D
A student has a liter of a 0.100 M solution of a strong acid. To prepare a buffer, this should be mixed with<n>A.a strong acid<n>B.a weak acid<n>C.a weak base<n>D.a strong base[SEP]C
Which of the following indicates that a reaction is spontaneous?<n>A.at equilibrium there are more products than reactants<n>B.the value of ΔG° is greater than zero<n>C.the value of ΔS° is greater than zero<n>D.the value of Keq is less than one[SEP]A
Which of the following is expected to have the largest bond polarity?<n>A.S–O<n>B.P–F<n>C.C–B<n>D.C–N[SEP]B
A mechanism is a sequence of elementary reactions that add up to the overall reaction stoichiometry. A substance that is produced in one elementary reaction and consumed in another is called<n>A.a catalyst<n>B.an intermediate<n>C.a reactant<n>D.a complex[SEP]B
Approximately how many half-lives will it take to reduce 10.0 kg of a radioactive substance to 1.0 microgram of that substance?<n>A.8<n>B.13<n>C.29<n>D.34[SEP]D
S(s) + O2(g) → SO2(g)<n>A.either S(s) or O2(g) will be completely used up<n>B.Q must be close to 1.0 since there is one mole of gas on each side of the equation<n>C.this reaction goes to completion<n>D.adding O2 will change the equilibrium constant[SEP]B
Three half-lives after an isotope is prepared,<n>A.25% of the isotope is left<n>B.25% of the isotope decayed<n>C.12.5% of the isotope is left<n>D.12.5% of the isotope decayed[SEP]C
Which pair of reactants will have no net ionic equation (that is, all the ions cancel)?<n>A.Na2SO3 + FeCl2<n>B.CaCl2 + MnSO4<n>C.NH4I + Pb(NO3)2<n>D.KOH + HClO4[SEP]B
Which of the following is expected to be the least soluble in water?<n>A.NaBr<n>B.NiSO3<n>C.CrCl3<n>D.Mn(NO3)2[SEP]B
The rate law may be written using stoichiometric coefficients for which of the following?<n>A.Precipitation reactions<n>B.Acid-base reactions<n>C.Elementary processes<n>D.Solubility reactions[SEP]C
A liquid element that is a dark-colored, nonconducting substance at room temperature is<n>A.mercury<n>B.bromine<n>C.iodine<n>D.bismuth[SEP]B
The molecule with a tetrahedral shape is<n>A.PCl4F<n>B.BF3<n>C.CO2<n>D.CBr4[SEP]D
The ideal gas law is successful for most gases because<n>A.room temperature is high<n>B.volumes are small<n>C.gas particles do not interact significantly<n>D.gases are dimers[SEP]C
What is an alpha particle?<n>A.Another name for an electron<n>B.Another name for a helium nucleus<n>C.Another name for a positron<n>D.Another name for a cosmic ray[SEP]B
Your supervisor asks you to determine the enthalpy of a certain chemical reaction. Which would you do?<n>A.Measure the ΔS and the ΔG for the reaction, and calculate the ΔH from the Gibbs free energy equation.<n>B.Use a bomb calorimeter to measure the heat of the reaction.<n>C.Use a solution calorimeter such as a coffee-cup calorimeter to measure the heat.<n>D.Use a photoelectron spectrometer to measure the energies of all atoms in the compounds, and use Hess's law to add them.[SEP]C
The bond length between any two nonmetal atoms is achieved under which of the following conditions?<n>A.Where the energy of interaction between the atoms is at its minimum value<n>B.Where the nuclei of each atom exhibits the strongest attraction to the electrons of the other atom<n>C.The point at which the attractive and repulsive forces between the two atoms are equal<n>D.The closest point at which a valence electron from one atom can transfer to the other atom[SEP]A
The oxidation number of chlorine in the perchlorate ion, ClO4–, is<n>A.2<n>B.-3<n>C.-1<n>D.7[SEP]D
There are a number of experiments for the determination of the molecular mass of a gas. One method begins by heating a solid or liquid in a flask to produce a gaseous product. The gas passes through a tube and displaces water in an inverted, water-filled bottle. The mass of the starting material is measured, along with the volume of the displaced water and the temperature of the system. The pressure in the inverted water-filled bottle is equal to the external pressure. Once the barometric pressure has been recorded, what other information is needed to finish the experiment?<n>A.The heat of formation of the gas<n>B.The density of the water<n>C.The mass of the displaced water<n>D.The vapor pressure of the water[SEP]D
The melting point of straight-chain hydrocarbons increases as the number of carbon atoms increase. The reason for this is the<n>A.increasing mass of the compounds<n>B.increasing polarity of the compounds<n>C.increasing number of induced dipoles per molecule<n>D.increased probability of hydrogen bonds[SEP]C
A sample of a compound known to consist of only carbon, hydrogen, and oxygen is found to have a total mass of 29.05 g. If the mass of the carbon is 18.02 g and the mass of the hydrogen is 3.03 g, what is the empirical formula of the compound?<n>A.C2H4O<n>B.C3H6O<n>C.C2H6O3<n>D.C3H8O2[SEP]B
Which would be the easiest way to burn an iron nail?<n>A.Hold an iron nail with crucible tongs, and heat strongly in the flame of a Bunsen burner.<n>B.Use the method in (A), but use an oxyacetylene torch to reach a higher temperature.<n>C.Grind the nail into very small, dust-sized particles, and spray them into a flame<n>D.Dissolve the nail in acid to make the oxide.[SEP]C
Which of the following has an octet of electrons around the central atom?<n>A.BF3<n>B.NH4+<n>C.PF5<n>D.SF6[SEP]B
How many milliliters of 0.250 M KOH does it take to neutralize completely 50.0 mL of 0.150 M H3PO4?<n>A.30.0 mL<n>B.27 mL<n>C.90.0 mL<n>D.270 mL[SEP]C
NH4+(aq) + NO2- (aq) → N2(g) + 2H2O(l) Increasing the temperature of the above reaction will increase the rate of reaction. Which of the following is NOT a reason that increased temperature increases reaction rate?<n>A.The reactants will be more likely to overcome the activation energy.<n>B.The number of collisions between reactant molecules will increase.<n>C.A greater distribution of reactant molecules will have high velocities.<n>D.Alternate reaction pathways become available at higher temperatures.[SEP]D
The relationship between the vapor pressure of a liquid and the heat of vaporization is expressed in the<n>A.Rydberg equation<n>B.Gibbs free energy equation<n>C.Clausius-Clapeyron equation<n>D.Arrhenius equation[SEP]C
Of the following pairs of elements, which pair has the second element with the larger electronegativity based on its position in the periodic table?<n>A.Oxygen, chromium<n>B.Chlorine, iodine<n>C.Calcium, cesium<n>D.Sulfur, nitrogen[SEP]D
The units for R, the ideal gas law equation constant, may be<n>A.L atm mol-1 K-1<n>B.J mol-1 K-1<n>C.volt coulomb mol-1 K-1<n>D.(A), (B), and (C)[SEP]D
Which of the following pair of liquids is expected to be immiscible?<n>A.H2O and CH3OH<n>B.C6H6 and C5H12<n>C.C10H22 and CH2CH2CH2OH<n>D.CH3CH2NH2 and CH3CH2CH2OH[SEP]C
Of the following, the most important experimental information used to deduce the structure of the atom was<n>A.the density of each element<n>B.the specific heat capacity<n>C.the emission spectrum of the elements, particularly hydrogen<n>D.the X-rays emitted from each element[SEP]C
para-dichlorobenzene is used as "mothballs." This compound can also be named<n>A.1,2-dichlorobenzene<n>B.1,3-dichlorobenzene<n>C.2,4-dichlorobenzene<n>D.1,4-dichlorobenzene[SEP]D
Radon is a health hazard because<n>A.it is a gas that can be inhaled and then it may decay to a solid that resides in the lungs<n>B.it is a gas that is extremely soluble in the bloodstream, and it decays in vital organs<n>C.it is a gas that enters the body easily and targets the thyroid because it is chemically similar to iodine<n>D.it is a gas that enters the body easily and targets bones because it is chemically similar to calcium[SEP]A
Each resonance form of the nitrate ion, NO3-, has how many sigma and how many pi bonds?<n>A.1 sigma and 2 pi<n>B.2 sigma and 1 pi<n>C.1 sigma and 1 pi<n>D.3 sigma and 1 pi[SEP]D
Which of the following can form hydrogen bonds?<n>A.CH3OCH2CH3<n>B.HCN<n>C.CH3OCH2Br<n>D.CH3NH2[SEP]D
The functional group that represents an organic acid is written as (Note: R represents the rest of the molecule)<n>A.RCHO<n>B.ROH<n>C.RCOOH<n>D.RCl[SEP]C
A certain radioactive material has a half-life of 36 minutes. Starting with 10.00 grams of this material, how many grams will be left after 2 hours?<n>A.1.00 grams<n>B.1.5 × 10^-4 grams<n>C.3.33 grams<n>D.0.25 gram[SEP]A
What is the pH of a solution prepared by dissolving 0.1665 mole of hypochlorous acid (HClO) in enough water to make 500 mL of solution? The Ka is 3.0 × 10^-4<n>A.1<n>B.2<n>C.5.4 × 10^-3<n>D.1.76[SEP]B
Iron(III) hydroxide has Ksp = 1.6 × 10^-39. What is the molar solubility of this compound?<n>A.8.8 × 10^-11 M<n>B.2.0 × 10^-10 M<n>C.7.4 × 10^-14 mol/L<n>D.9.4 × 10^-6 mol/L[SEP]A
The subatomic particle with the most penetrating ability is<n>A.a beta particle<n>B.a neutron<n>C.a proton<n>D.an alpha particle[SEP]A
Consider the Lewis structures for the following molecules: CO2, CO32-, NO2-, and NO3-. Which molecule or molecules exhibit sp2 hybridization around the central atom?<n>A.CO2 and CO32-<n>B.NO2- and NO3-<n>C.CO32- and NO3-<n>D.CO32-, NO2- and NO3-[SEP]D
The photoelectron spectrum of carbon has three equally sized peaks. What peak is at the lowest energy?<n>A.The 1s peak has the lowest energy.<n>B.The 2s peak has the lowest energy.<n>C.The 2p peak has the lowest energy.<n>D.The 1p peak has the lowest energy.[SEP]C
The electrolysis of molten magnesium bromide is expected to produce<n>A.magnesium at the anode and bromine at the cathode<n>B.magnesium at the cathode and bromine at the anode<n>C.magnesium at the cathode and oxygen at the anode<n>D.bromine at the anode and hydrogen at the cathode[SEP]B
The Arrhenius equation may be used to determine<n>A.the activation energy of a reaction<n>B.the rate constant at various temperatures<n>C.the shelf life of a consumer product or drug<n>D.all of the above[SEP]D
Nickel (Z = 28, A = 59) has a first ionization energy of 737 kJ/mol and a boiling point of 2913 °C, while Pt (Z = 78, A = 195) has a first ionization energy of 870 kJ/mol and a boiling point of 3825 °C. Which of the following are the most reasonable values of ionization energy and boiling point for palladium?<n>A.-200 kJ/mol and 3524 °C<n>B.795 kJ/mol and 2436 °C<n>C.804 kJ/mol and 2963 °C<n>D.932 kJ/mol and 3416 °C[SEP]C
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<n>A.6 electrons on the left<n>B.6 electrons on the right<n>C.3 electrons on the left<n>D.10 electrons on the left[SEP]D
0.0025 mol of a weak, monoprotic acid is dissolved in 0.250 L of distilled water. The pH was then measured as 4.26. What is the pKa of this weak acid?<n>A.4.26<n>B.8.52<n>C.7.92<n>D.6.52[SEP]D
Potassium-40 is a minor isotope found in naturally occurring potassium. It is radioactive and can be detected on simple radiation counters. How many protons, neutrons, and electrons does potassium-40 have when it is part of K2SO4?<n>A.21 neutrons, 19 protons, 18 electrons<n>B.20 neutrons, 19 protons, 19 electrons<n>C.21 neutrons, 19 protons, 19 electrons<n>D.19 neutrons, 19 protons, 19 electrons[SEP]A
Which of the following reactions is expected to have the greatest decrease in entropy?<n>A.HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)<n>B.CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l)<n>C.C(s) + O2(g) → CO2(g)<n>D.2 SO2(g) + O2(g) → 2 SO3(g)[SEP]B
What is the ionization constant, Ka, for a weak monoprotic acid if a 0.060 molar solution has a pH of 2.0?<n>A.2.0 × 10^-3<n>B.2.0 × 10^-1<n>C.1.7 × 10^-1<n>D.5.0 × 10^-3[SEP]A
Solvents A and B form an ideal solution. Solvent A has a vapor pressure of 345 torr at room temperature. At the same temperature, solvent B has a vapor pressure of 213 torr. What is the vapor pressure of a mixture where the mole fraction of A is 0.285?<n>A.213 torr<n>B.345 torr<n>C.568 torr<n>D.251 torr[SEP]D
Which of the following is the strongest Brønsted-Lowry acid?<n>A.HBrO<n>B.HBrO3<n>C.HBrO2<n>D.HBrO4[SEP]D
Which of the following molecules cannot hydrogen bond with molecules identical to itself but can hydrogen bond with one of the molecules above or below it in the following responses?<n>A.CH3CH2OH<n>B.CH3CH2COOH<n>C.CH3CH2CHO<n>D.C6H5CHO[SEP]C
Which following pair of substances can be used to make a buffer solution?<n>A.NaCl and HCl<n>B.HC2H3O2 and KC2H3O2<n>C.NaBr and KBr<n>D.HIO3 and KClO3[SEP]B
In which of the following is the negative end of the bond written last?<n>A.O—S<n>B.Br—N<n>C.N—C<n>D.P—Cl[SEP]D
When will Kp and Kc have the same numerical value?<n>A.At absolute zero for all reactions<n>B.When the concentrations are at standard state<n>C.When the concentrations are all 1.00 molar<n>D.When the reaction exhibits no change in pressure at constant volume[SEP]D
Silver metal, often amalgamated with mercury, is used to reduce substances to a desired oxidation state. If the silver metal amalgam cannot be used because of concerns about mercury, which of the following would be a reasonable and safe substitute?<n>A.H+(aq)<n>B.Na(s)<n>C.Ca2+(aq)<n>D.Mg(s)[SEP]D
PCl3(g) + Cl2(g) ↔ PCl5(g) ΔH = -92.5 kJ/mol In which of the following ways could the reaction above be manipulated to create more product?<n>A.Decreasing the concentration of PCl3<n>B.Increasing the pressure<n>C.Increasing the temperature<n>D.None of the above[SEP]B
A 25 g sample of a liquid was heated to 100 °C and then quickly transferred to an insulated container holding 100 g of water at 22 °C. The temperature of the mixture rose to reach a final temperature of 35 °C. Which of the following can be concluded?<n>A.The sample temperature changed more than the water temperature did; therefore the sample lost more heat energy than the water gained.<n>B.The sample temperature changed more than the water temperature did, but the sample lost the same amount of heat energy as the water gained.<n>C.The sample temperature changed more than the water temperature did; therefore the CP of the sample must be greater than the CP of the water.<n>D.The final temperature is less than the average starting temperature of the sample and the water; therefore the total energy of the sample and water decreased.[SEP]B
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?<n>A.Their velocity increases by a factor of two.<n>B.Their velocity increases by a factor of four.<n>C.Their kinetic energy increases by a factor of 2.<n>D.Their kinetic energy increases by a factor of less than 2.[SEP]D
What is the empirical formula of a compound that is 51.9% carbon, 4.86% hydrogen, and 43.2% bromine<n>A.C7H5Br<n>B.C6H4Br3<n>C.C8H9Br<n>D.C12H22Br[SEP]C
Three steel containers hold gas samples. The containers are all the same size and at the same temperature. One container has 4.0 g of helium, another has 28.0 g of nitrogen, and the third has 44.0 g of carbon dioxide. Pick the FALSE statement from the following list:<n>A.The densities increase in the order helium < nitrogen < carbon dioxide.<n>B.The number of molecules in all the containers is the same.<n>C.The pressure in all three containers is the same.<n>D.The average speed of all the molecules is the same.[SEP]D
Determine the final temperature, in °C, of a sample of helium gas. The sample initially occupied a volume of 5.00 L at 127°C and 875 mm Hg. The sample was heated, at constant pressure, until it occupied a volume of 10.00 L.<n>A.454°C<n>B.527°C<n>C.45°C<n>D.181°C[SEP]B
Substances whose Lewis structures must be drawn with an unpaired electron are called<n>A.ionic compounds<n>B.free radicals<n>C.resonance structures<n>D.polar molecules[SEP]B
Which of the following molecules is expected to have the highest normal boiling point?<n>A.CH3CH2CH2CH3<n>B.CH3CH2CH2CH2OH<n>C.CH3CH2CH2CH2Cl<n>D.CH3CH2CH2CH2Br[SEP]B
Which net ionic equation below represents a possible reaction that takes place when a strip of magnesium metal is oxidized by a solution of chromium (III) nitrate?<n>A.Mg(s) + Cr(NO3)3(aq) → Mg2+(aq) + Cr3+(aq) + 3NO3-(aq)<n>B.3Mg(s) + 2Cr3+ → 3Mg2+ + 2Cr(s)<n>C.Mg(s) + Cr3+ → Mg2+ + Cr(s)<n>D.3Mg(s) + 2Cr(NO3)3(aq) → 3Mg2+(aq) + 2Cr(s) + NO3-(aq)[SEP]B
What is the conjugate acid of the H2PO4- ion?<n>A.HPO42-<n>B.H2PO4-<n>C.H3PO4<n>D.PO43-[SEP]C
A 25 g sample of a solid was heated to 100 °C and then quickly transferred to an insulated container holding 100 g of water at 26 °C. The temperature of the mixture rose to reach a final temperature of 37 °C. Which of the following can be concluded?<n>A.The sample lost more thermal energy than the water gained because the sample temperature changed more than the water temperature did.<n>B.Even though the sample temperature changed more than the water temperature did, the sample lost the same amount of thermal energy as the water gained.<n>C.The sample temperature changed more than the water temperature did; therefore the heat capacity of the sample must be greater than the heat capacity of the water.<n>D.The final temperature is less than the average starting temperatures; therefore the equilibrium constant must be less than 1.[SEP]B
Which of the following processes is an irreversible reaction?<n>A.CH4(g) + O2(g) → CO2(g) + H2O(l)<n>B.HCN(aq) + H2O(l) → CN-(aq) + H3O+(aq)<n>C.Al(NO3)3(s) → Al3+(aq) + 3NO3-(aq)<n>D.2Ag+(aq) + Ti(s) → 2Ag(s) + Ti2+(aq)[SEP]A
Starting with a stock solution of 18.0 M H2SO4, what is the proper procedure to create a 1.00 L sample of a 3.0 M solution of H2SO4 in a volumetric flask?<n>A.Add 167 mL of the stock solution to the flask, then fill the flask the rest of the way with distilled water while swirling the solution.<n>B.Add 600 mL of the stock solution to the flask, then fill the flask the rest of the way with distilled water while swirling the solution.<n>C.Fill the flask partway with water, then add 167 mL of the stock solution, swirling to mix it. Last, fill the flask the rest of the way with distilled water.<n>D.Fill the flask partway with water, then add 600 mL of the stock solution, swirling to mix it. Last, fill the flask the rest of the way with distilled water.[SEP]C
Which of the following does not contain oxygen?<n>A.An aldehyde<n>B.An alkane<n>C.An alcohol<n>D.An ether[SEP]B
Formation of a solution can often be visualized as a three-step process. Step 1. Solvent molecules are separated from each other to make space for the solute. Step 2. Solute molecules are separated so they fit into spaces in the solvent. Step 3. Separated solute and solvent are brought together, filling in the spaces. Which of the following statements about the energy involved in the above is correct?<n>A.Steps 1 and 2 are exothermic, and step 3 is endothermic.<n>B.Steps 1 and 2 are endothermic, and step 3 is exothermic.<n>C.All three steps are exothermic.<n>D.All three steps are endothermic.[SEP]B
Consider the Lewis structures for the following molecules: CO2, CO32-, NO2-, and NO3-. Which molecule would have the shortest bonds?<n>A.CO2<n>B.CO32-<n>C.NO2-<n>D.NO3-[SEP]A
In determining the order for reactant A in a certain reaction, the concentrations of all other reactants are held constant while the concentration of A is tripled from one experiment to another. The reaction rate is found to triple. The appropriate exponent for A in the rate law is<n>A.1<n>B.2<n>C.3<n>D.4[SEP]A
The simplest alkene has<n>A.at least two pi bonds<n>B.at least four sigma bonds<n>C.a tetrahedral configuration<n>D.cis-trans isomers[SEP]B
2Ag+(aq) + Fe(s) → 2Ag(s) + Fe2+(aq) Which of the following would cause an increase in potential in the voltaic cell described by the above reaction?<n>A.Increasing [Fe2+]<n>B.Adding more Fe(s)<n>C.Decreasing [Fe2+]<n>D.Removing some Fe(s)[SEP]C
Hypochlorous acid is an unstable compound, and one of the decomposition products is chlorine gas, Cl2. The decomposition of the acid lowers its concentration over time. What effect will the decomposition of one-fourth of the acid have on the agreement between the endpoint of the titration and the equivalence point during a titration with standard sodium hydroxide?<n>A.The endpoint would still remain near the ideal equivalence point.<n>B.The endpoint would be after the ideal equivalence point.<n>C.The endpoint would be before the ideal equivalence point.<n>D.It is impossible to determine.[SEP]C
The name for CH3CHBrCHClCH2CH3 is<n>A.dibromotrichloropropane<n>B.dibromotrichloropentane<n>C.2-bromo, 3-chloropentane<n>D.2,3-bromochloropentane[SEP]C
Under which conditions will a real gas most closely behave as an ideal gas?<n>A.High temperature and high pressure<n>B.High temperature and low pressure<n>C.High volume and high temperature<n>D.Low temperature and low pressure[SEP]B
How many electrons, neutrons, and protons are in an atom of 52Cr?<n>A.24 electrons, 24 protons, 24 neutrons<n>B.27 electrons, 27 protons, 24 neutrons<n>C.24 electrons, 28 protons, 24 neutrons<n>D.24 electrons, 24 protons, 28 neutrons[SEP]D
S(s) + O2(g) → SO2(g)<n>A.one atom of S reacts with one molecule of O2 to yield one molecule of SO2<n>B.one mole of sulfur atoms reacts with one mole of oxygen molecules to yield one mole of sulfur dioxide molecules<n>C.this reaction goes to completion<n>D.adding S(s) will change the equilibrium constant[SEP]D
Sulfur dioxide reacts with oxygen to form sulfur trioxide in the presence of a catalyst. The equilibrium constant, Kp, at a certain temperature is 3.0 × 10^22. A 2.0-liter flask has enough SO3 added to it to produce a pressure of 0.789 atm Hg. After the reaction comes to equilibrium, the expected partial pressure of O2 will be<n>A.2.88 × 10^-6 torr<n>B.3 × 10^-18 mm Hg<n>C.1100 mm Hg<n>D.1.32 × 10^-5 torr[SEP]D
How many electrons, neutrons, and protons are in an atom of Cr?<n>A.24 electrons, 24 protons, 24 neutrons<n>B.27 electrons, 27 protons, 24 neutrons<n>C.24 electrons, 28 protons, 24 neutrons<n>D.more information is needed to answer this question[SEP]D
When an ideal gas is allowed to expand isothermally, which one of the following is true?<n>A.q = 0<n>B.w = 0<n>C.E = 0<n>D.q = -w[SEP]D
An ideal solution is a<n>A.mixture where two solvents can be dissolved in all ratios<n>B.mixture that has the same physical properties as the individual solvents<n>C.mixture where the potential energy of the mixture is the same as that of the individual solvents<n>D.mixture that is colorless[SEP]C
Which of the following is true for all bases?<n>A.All bases donate OH- ions into solution.<n>B.Only strong bases create solutions in which OH- ions are present.<n>C.Only strong bases are good conductors when dissolved in solution.<n>D.For weak bases, the concentration of the OH-ions exceeds the concentration of the base in the solution.[SEP]C
The Pauli exclusion principle states that<n>A.no two electrons can have the same four quantum numbers<n>B.no two electrons with the same spin can occupy an orbital<n>C.no two electrons can occupy separate orbitals<n>D.no two electrons can pair up if there is an empty orbital available[SEP]A
Joseph Priestly discovered oxygen gas by the decomposition of solid mercury(II) oxide, HgO, to oxygen gas, O2, and liquid mercury metal, Hg. How many moles of oxygen gas will form when 4.32 g of solid mercury(II) oxide decomposes? The formula mass of mercury(II) oxide is 216 g mol^-1.<n>A.0.100 mol<n>B.0.0100 mol<n>C.0.0200 mol<n>D.0.0150 mol[SEP]B
Atoms of four elements are examined: carbon, nitrogen, neon, and sulfur. Atoms of which element are most likely to form a structure with the formula XF6 (where X is one of the four atoms)?<n>A.Carbon<n>B.Nitrogen<n>C.Neon<n>D.Sulfur[SEP]D
Chlorine gas reacts most readily with<n>A.toluene<n>B.ethylene<n>C.ethanoic acid<n>D.ethane[SEP]B
An ester is made by reacting<n>A.an amine and an alcohol<n>B.two different alcohols<n>C.an alcohol and an acid<n>D.an acid and a base[SEP]C
Atoms of four elements are examined: carbon, nitrogen, neon, and sulfur. Which element would have a photoelectron spectra in which the peak representing electrons with the lowest ionization energy would be three times higher than all other peaks?<n>A.Carbon<n>B.Nitrogen<n>C.Neon<n>D.Sulfur[SEP]C
What is the work involved if a gas in a 2.0-liter container at 2.4 atmospheres pressure is allowed to expand against a pressure of 0.80 atmosphere?<n>A.-3.2 L atm<n>B.-9.62 L atm<n>C.-4.8 L atm<n>D.+14.4 L atm[SEP]A
Which of the following is incorrectly named?<n>A.CaCl2   calcium chloride<n>B.Fe(NO3)3   iron(III) nitrate<n>C.AlBr3   aluminum tribromide<n>D.K2Cr2O7   potassium dichromate[SEP]C
The standard state for redox reactions includes<n>A.the temperature is 25 °C<n>B.concentrations of soluble species are 1 molar<n>C.partial pressures of gases are 1 atmosphere<n>D.all of the above are true[SEP]D
Chemists often ascribe the macroscopic properties of solids to the underlying microscopic structure. Silicon carbide is almost as hard and brittle as diamond. The solid state structure of silicon carbide is often described as<n>A.a molecular crystal<n>B.a covalent or network crystal<n>C.a metallic crystal<n>D.an ionic crystal[SEP]B
Which of the following may need to be balanced using the ion-electron method ?<n>A.BaCl2 + Al2(SO4)3 → AlCl3 + BaSO4<n>B.H+ + OH- → H2O<n>C.NaOH + H3PO4 → Na2HPO4 + H2O<n>D.C2H2(g) + N2O(g) → CO2(g) + H2O(g) + N2(g)[SEP]D
A solution is prepared by dissolving 30.0 grams of Ni(NO3)2 in enough water to make 250 mL of solution. What is the molarity of this solution?<n>A.0.496 molar<n>B.0.656 mol/L<n>C.3.3 molar<n>D.6.3 × 10^-3 molar[SEP]B
A solution of a weak base is titrated with a solution of a standard strong acid. The progress of the titration is followed with a pH meter. Which of the following observations would occur?<n>A.Initially, the pH slowly decreases, then there is a rapid decrease to give a pH below 7 at the equivalence point.<n>B.The pH of the solution gradually decreases throughout the experiment and the pH at the equivalence point is below 7.<n>C.Initially, the pH slowly decreases, then there is a rapid decrease to give a pH equal to 7 at the equivalence point.<n>D.Initially, the pH quickly decrease, then there is a gradual decrease to the equivalence point where the pOH equals the pKb of the base.[SEP]A
A 25 g sample of a liquid was heated to 95 °C and then quickly transferred to an insulated container holding 100 g of water at 26 °C. The temperature of the mixture rose to reach a final temperature of 37 °C. Which of the following can be concluded?<n>A.The sample lost more heat energy than the water gained because the sample temperature changed more than the water temperature did.<n>B.The final temperature is less than the average starting temperatures; therefore the equilibrium constant must be less than 1.<n>C.The sample temperature changed more than the water temperature did; therefore the heat capacity of the sample must be greater than the heat capacity of the water.<n>D.Even though the sample temperature changed more than the water temperature did, the sample lost the same amount of heat energy as the water gained to obey the law of conservation of energy.[SEP]D
Changing which of the following will change the numerical value of the equilibrium constant?<n>A.The pressure of reactants<n>B.The pressure of products<n>C.The temperature<n>D.The total mass of the chemicals present[SEP]C
What is the general relationship between temperature and entropy for diatomic gases?<n>A.They are completely independent of each other; temperature has no effect on entropy.<n>B.There is a direct relationship, because at higher temperatures there is an increase in energy dispersal.<n>C.There is an inverse relationship, because at higher temperatures substances are more likely to be in a gaseous state.<n>D.It depends on the specific gas and the strength of the intermolecular forces between individual molecules.[SEP]B
Nitrogen's electronegativity value is between those of phosphorus and oxygen. Which of the following correctly describes the relationship between the three values?<n>A.The value for nitrogen is less than that of phosphorus because nitrogen is larger, but greater than that of oxygen because nitrogen has a greater effective nuclear charge.<n>B.The value for nitrogen is less than that of phosphorus because nitrogen has fewer protons but greater than that of oxygen because nitrogen has less valence electrons.<n>C.The value for nitrogen is greater than that of phosphorus because nitrogen has less electrons, but less than that of oxygen because nitrogen is smaller.<n>D.The value for nitrogen is greater than that of phosphorus because nitrogen is smaller, but less than that of oxygen because nitrogen has a smaller effective nuclear charge.[SEP]D
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?<n>A.KCl(aq)<n>B.Fe(NO3)3(aq)<n>C.MgSO4 (aq)<n>D.N2H4(aq)[SEP]D
The dimerization of NO2(g) to N2O4(g) is an endothermic process. Which of the following will, according to Le Châtelier's principle, increase the amount of N2O4 in a reaction vessel?<n>A.Decreasing the temperature<n>B.Increasing the size of the reaction vessel<n>C.Adding a selective catalyst<n>D.Making the reaction vessel smaller[SEP]D
Cerium(III) sulfate, Ce2(SO4)2, is less soluble in hot water than it is in cold. Which of the following conclusions may be related to this?<n>A.The heat of solution of cerium(III) sulfate is exothermic.<n>B.The hydration energies of cerium ions and sulfate ions are very low.<n>C.The heat of solution for cerium(III) sulfate is endothermic.<n>D.The solution is not an ideal solution.[SEP]A
The weight percent of sodium hydroxide dissolved in water is 50%. What is the mole fraction of sodium hydroxide?<n>A.31.00%<n>B.0.164<n>C.0.311<n>D.0.5[SEP]C
The most massive subatomic particle is the<n>A.proton<n>B.neutron<n>C.alpha particle<n>D.beta particle[SEP]C
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?<n>A.1<n>B.4<n>C.5<n>D.11[SEP]B
Which of the following geometries corresponds to a substance that has five sigma bonds and one nonbonding pair of electrons?<n>A.Tetrahedron<n>B.Square planar<n>C.Octahedron<n>D.Square pyramid[SEP]D
Which of the following should be named using Roman numerals after the cation?<n>A.CaCl2<n>B.CuCl2<n>C.AlBr3<n>D.K2Cr2O7[SEP]B
Which of the following is not a good measure of relative intermolecular attractive forces?<n>A.Heat of fusion<n>B.Boiling points<n>C.Vapor pressures<n>D.Heat of vaporization[SEP]A
The Pauli exclusion principle states that<n>A.no two electrons can have the same energy<n>B.no two electrons can have the same four quantum numbers<n>C.no two electrons can occupy separate orbitals<n>D.no two electrons can pair up if there is an empty orbital available[SEP]B
Chlorine is often used to oxidize other substances. It makes a good bleach because it can oxidize many colored compounds. If chlorine is not available, what other substance can be used for oxidizing substances?<n>A.Al<n>B.H2S<n>C.Zn<n>D.KMnO4[SEP]D
A proposed mechanism for a reaction is as follows: NO2 + F2 →NO2F + F Slow step. F + NO2 → NO2F Fast step. What is the order of the overall reaction?<n>A.Zero order<n>B.First order<n>C.Second order<n>D.Third order[SEP]C
The units for the rate of a chemical reaction are<n>A.L2 mol-2 s-1<n>B.mol L-1 s-1<n>C.L mol-1 s-1<n>D.it depends on the particular reaction[SEP]B
A stock solution of 12.0 M sulfuric acid is made available. What is the best procedure to make up 100. mL of 4.0 M sulfuric acid using the stock solution and water prior to mixing?<n>A.Add 33.3 mL of water to the flask, and then add 66.7 mL of 12.0 M acid.<n>B.Add 33.3 mL of 12.0 M acid to the flask, and then dilute it with 66.7 mL of water.<n>C.Add 67.7 mL of 12.0 M acid to the flask, and then dilute it with 33.3 mL of water.<n>D.Add 67.7 mL of water to the flask, and then add 33.3 mL of 12.0 M acid.[SEP]D
To prepare a buffer, all of the following are needed except<n>A.an acid with a pKa close to the desired pH<n>B.a conjugate acid along with its conjugate base<n>C.a buffer capacity sufficient to react with added acid or base<n>D.triple-distilled water[SEP]D
Of the following oxo acids, which is predicted to be the strongest acid?<n>A.HBrO<n>B.HClO<n>C.HIO<n>D.HClO3[SEP]D
According to the kinetic-molecular theory of gases,<n>A.the average kinetic energy of a gas particle is directly related to the Kelvin temperature<n>B.ideal gas particles do not attract or repel each other<n>C.the atoms or molecules of an ideal gas have no volume<n>D.(A), (B), and (C) are part of the theory[SEP]D
Three 25.00 mL samples of approximately 0.10 M phenol, C6H5OH, Ka = 1.0 × 10^-10 were removed from a container and placed in separate 250 mL beakers. The samples were titrated with standard potassium hydroxide, KOH, solution. Cresol red was the acid-base indicator used in the titration. The samples required 31.75, 32.38, and 41.75 mL to reach the endpoint. Which of the following might explain why one of the samples required significantly more base to reach the endpoint?<n>A.The indicator was added too late.<n>B.The wrong indicator was used.<n>C.There was a base contaminating the unclean beaker.<n>D.There was an acid contaminating the unclean beaker.[SEP]D
Which is correct about the calcium atom?<n>A.It contains 20 protons and neutrons<n>B.It contains 20 protons and 20 electrons<n>C.It contains 20 protons, neutrons, and electrons<n>D.All atoms of calcium have a mass of 40.078 u[SEP]B
Which of the following correctly lists the individual intermolecular attractive forces from the strongest to the weakest?<n>A.Induced dipole < dipole-dipole < hydrogen bond<n>B.Hydrogen bond < dipole-dipole < induced dipole<n>C.Induced dipole < hydrogen bond < dipole-dipole<n>D.Dipole-dipole < hydrogen bond < induced dipole[SEP]B
Identify the Brønsted-Lowry conjugate acid-base pair in the following list.<n>A.H3O+ and OH-<n>B.H3PO4 and H3PO3<n>C.HC2H3O2 and C2H3O2-<n>D.SO32- and SO22-[SEP]C
What is the mass of one molecule of cholesterol (C27H46O, molecular mass = 386)?<n>A.6.41 × 10^-22 g<n>B.1.5 × 10^-21 g<n>C.1.38 × 10^-21 g<n>D.3 × 10^-23 g[SEP]A
Using fundamental trends in electronegativity and bond strength, which of the following should be the strongest acid?<n>A.H2S<n>B.HI<n>C.HBr<n>D.H2O[SEP]B
Examining data obtained from mass spectrometry supports which of the following?<n>A.The common oxidation states of elements<n>B.Atomic size trends within the periodic table<n>C.Ionization energy trends within the periodic table<n>D.The existence of isotopes[SEP]D
When potassium perchlorate, KClO4, dissolves in water, the temperature of the resultant solution is lower than the initial temperature of the components. Which of the following conclusions may be related to this?<n>A.This is a spontaneous process because it is exothermic.<n>B.This is a spontaneous process because of an entropy increase.<n>C.This is a spontaneous process because of an entropy decrease.<n>D.This is a spontaneous process because it is exothermic.[SEP]B
Hard materials such as silicon carbide, used for grinding wheels, are said to be examples of<n>A.ionic crystals<n>B.network crystals<n>C.metallic crystals<n>D.molecular crystals[SEP]B
A solution of sulfurous acid, H2SO3, is present in an aqueous solution. Which of the following represents the concentrations of three different ions in solution?<n>A.[SO32-] > [HSO3-] > [H2SO3]<n>B.[H2SO3] > [HSO3-] > [SO32-]<n>C.[H2SO3] > [HSO3-] = [SO32-]<n>D.[SO32-] = [HSO3-] > [H2SO3][SEP]B
Which of the following is a reduction half-reaction? (1) Cu2+ + e- → Cu+ (2) Cu+ + e- → Cu0 (3) Fe2+ → Fe3+ + e-<n>A.1 only because copper(II) ions are reduced<n>B.3 only because the iron is reduced<n>C.1 and 2 because they both reduce copper ions<n>D.1 and 3 because they do not have insoluble ions[SEP]C
The first ionization energy for a neutral atom of chlorine is 1.25 MJ/mol and the first ionization energy for a neutral atom of argon is 1.52 MJ/mol. How would the first ionization energy value for a neutral atom of potassum compare to those values?<n>A.It would be greater than both because potassium carries a greater nuclear charge then either chlorine or argon.<n>B.It would be greater than both because the size of a potassium atom is smaller than an atom of either chlorine or argon.<n>C.It would be less than both because there are more electrons in potassium, meaning they repel each other more effectively and less energy is needed to remove one.<n>D.It would be less than both because a valence electron of potassium is farther from the nucleus than one of either chlorine or argon.[SEP]D
Which of the following is the correct order of increasing acid strength?<n>A.H2SeO3 < H2SO3 < HClO < HBrO<n>B.HClO < H2SeO3 < HBrO < H2SO3<n>C.HBrO < HClO < H2SeO3 < H2SO3<n>D.H2SO3 < H2SeO3 < HClO < HBrO[SEP]C
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?<n>A.NO2(g)<n>B.N2(g)<n>C.NO3-(aq)<n>D.NO2-(aq)[SEP]B
When using the ideal gas law, standard conditions for temperature and pressure are<n>A.0 K and 0 torr<n>B.25 °C and 1 atmosphere pressure<n>C.0 °C and 760 torr<n>D.0 °F and 1 atmosphere pressure[SEP]C
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?<n>A.Bromine is a liquid and boils; iodine is a solid and sublimes.<n>B.The intramolecular bonds in I2 are much weaker than those in Br2.<n>C.The I2 electron clouds are much more polarizable than the Br2 electron clouds, resulting in much stronger London forces.<n>D.The mass of iodine is much greater than the mass of bromine.[SEP]C
Atoms of four elements are examined: carbon, nitrogen, neon, and sulfur. Atoms of which element would have the strongest magnetic moment?<n>A.Carbon<n>B.Nitrogen<n>C.Neon<n>D.Sulfur[SEP]B
Argon can be liquefied at low temperature because of<n>A.dipole-dipole attractive forces<n>B.hydrogen bonding<n>C.instantaneous and induced dipoles<n>D.the very low temperature[SEP]C
Choose the reaction expected to have the greatest decrease in entropy.<n>A.C(s) + CO2(g) → 2 CO(g)<n>B.2 Na(s) + O2(g) → Na2O2(s)<n>C.CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g)<n>D.2 NI3(s) → 3 I2(s) + N2(g)[SEP]B
A 2.0 L flask holds 0.40 g of helium gas. If the helium is evacuated into a larger container while the temperature is held constant, what will the effect on the entropy of the helium be?<n>A.It will remain constant as the number of helium molecules does not change.<n>B.It will decrease as the gas will be more ordered in the larger flask.<n>C.It will decrease because the molecules will collide with the sides of the larger flask less often than they did in the smaller flask.<n>D.It will increase as the gas molecules will be more dispersed in the larger flask.[SEP]D
Chemical reactions can be classified as either heterogeneous or homogeneous. Which of the following equations below is best classified as a heterogeneous reaction?<n>A.2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(g)<n>B.C2H5OH(aq) + O2(aq) → HC2H3O2(aq) + H2O(aq)<n>C.C(s) + H2O(g) → H2(g) + CO(g)<n>D.C2H2(g) + 5N2O(g) → CO2(g) + H2O(g) + 5N2(g)[SEP]C
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?<n>A.212 g mol-1<n>B.4.70 g mol-1<n>C.147 g mol-1<n>D.682 g mol-1[SEP]A
An experiment was performed to determine the moles of carbon dioxide gas formed (collected over water) when an acid reacts with limestone. To do this, a piece of dry limestone was weighed. Then carbon dioxide was collected until the limestone disappeared. The atmospheric pressure was measured at 0.965 atm. The temperature was 295 K. The volume of CO2 was measured to the nearest mL and corrected for the vapor pressure of water. The student continuously got low results from what was expected. Can you suggest why?<n>A.Limestone is never pure CaCO3.<n>B.Limestone is Ca(HCO3)2.<n>C.Carbon dioxide is rather soluble in water.<n>D.Perhaps there was not enough acid to dissolve all the limestone.[SEP]C
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?<n>A.[HNO2] > [NO2-]<n>B.[NO2-] > [HNO2]<n>C.[H2NO2+] > [HNO2]<n>D.[HNO2] > [H2NO2+][SEP]B
Which of the following best explains why the ionization of atoms can occur during photoelectron spectroscopy, even though ionization is not a thermodynamically favored process?<n>A.It is an exothermic process due to the release of energy as an electron is liberated from the Coulombic attraction holding it to the nucleus.<n>B.The entropy of the system increases due to the separation of the electron from its atom.<n>C.Energy contained in the light can be used to overcome the Coulombic attraction between electrons and the nucleus.<n>D.The products of the ionization are at a lower energy state than the reactants.[SEP]C
During the investigation of a chemical reaction by a chemistry student, she was able to determine that the reaction was nonspontaneous at 1 atm and 298 K. However, she learned that cooling the system with dry ice (-78°C) caused the reaction to become spontaneous. Which of the following combinations must apply to this reaction?<n>A.ΔH < 0, ΔS < 0, and ΔG = 0<n>B.ΔH > 0, ΔS < 0, and ΔG > 0<n>C.ΔH < 0, ΔS < 0, and ΔG > 0<n>D.ΔH > 0, ΔS > 0, and ΔG > 0[SEP]C
Which of the following is a balanced chemical reaction?<n>A.Na2SO4 + Ba(NO3)2 → BaSO4 + NaSO4<n>B.AgNO3 + K2CrO4 → Ag2CrO4 + 2 KNO3<n>C.5 FeCl2 + 8 HCl + KMnO4 → 5 FeCl3 + MnCl2 + 4 H2O + KCl<n>D.Al(NO3)3 + 3 KOH → Al(OH)3 + KNO3[SEP]C
Identify the Brønsted-Lowry conjugate acid-base pair in the following list.<n>A.H3O+ and OH-<n>B.H3PO4 and H2PO4-<n>C.HClO4 and ClO3-<n>D.SO32- and HSO2-[SEP]B
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?<n>A.1s<n>B.2p<n>C.3p<n>D.3d[SEP]C
Sulfurous acid is a weak acid, while sulfuric acid is a much stronger acid because<n>A.the sulfur in sulfuric acid is more electronegative than the sulfur in sulfurous acid<n>B.sulfuric acid has more oxygen atoms in its formula<n>C.the O–H bonds in sulfuric acid are much weaker than those in sulfurous acid<n>D.sulfurous acid has its hydrogen atoms bound directly to the sulfur atom[SEP]C
Which of the following is a radioactive element?<n>A.Na<n>B.Cr<n>C.Am<n>D.Al[SEP]C
Which of the following is expected to have two or more resonance structures?<n>A.CCl2F2<n>B.SO3<n>C.PF5<n>D.H2O[SEP]B
Formation of a solution can often be visualized as a three-step process. Step 1. Solvent molecules are separated from each other to make space for the solute. Step 2. Solute molecules are separated so they fit into spaces in the solvent. Step 3. Separated solute and solvent are brought together filling in the spaces.All of the fundamental principles below are important in understanding the formation of solutions except which one?<n>A.Starting at equilibrium, moving particles apart while in the solid or equilibrium phases requires added energy proportional to the attractive forces.<n>B.Bringing particles together releases energy in proportion to their attractive forces.<n>C.The total of the energies in steps 1 to 3 indicates if a solution will form.<n>D.Molecules with similar molecular masses are required to form solutions.[SEP]D
Most transition metals share a common oxidation state of +2. Which of the following best explains why?<n>A.Transition metals all have a minimum of two unpaired electrons.<n>B.Transition metals have unstable configurations and are very reactive.<n>C.Transition metals tend to gain electrons when reacting with other elements.<n>D.Transition metals will lose their outermost s-block electrons when forming bonds.[SEP]D
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?<n>A.10.80%<n>B.4.60%<n>C.43.50%<n>D.18%[SEP]B
Nitrous acid is a weak acid, while nitric acid is a much stronger acid because<n>A.the nitrogen in nitric acid is more electronegative than the nitrogen in nitrous acid<n>B.nitric acid has more oxygen atoms in its formula<n>C.the –O–H bonds in nitric acid are much weaker than in nitrous acid due to the electron withdrawing of more oxygen atoms on nitric acid<n>D.nitric acid has the hydrogen atoms bound directly to the nitrogen atom[SEP]C
Determine the H+(aq) concentration in 1.0 M phenol, C6H5OH, solution. (The Ka for phenol is 1 × 10^-10.)<n>A.1 × 10^-10 M<n>B.1 × 10^-9 M<n>C.1 × 10^-3 M<n>D.1 × 10^-5 M[SEP]D
The equilibrium constant, Kc, for the dissociation of HI into hydrogen gas and iodine vapor is 21 at a certain temperature. What will be the molar concentration of iodine vapor if 15 grams of HI gas is introduced into a 12.0-L flask and allowed to come to equilibrium?<n>A.4.58 mol/L<n>B.0.00687 mol L-1<n>C.4.4 × 10^-3 M<n>D.9.76 × 10^-3 M[SEP]C
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?<n>A.4.26<n>B.8.52<n>C.7.52<n>D.3.66[SEP]B
Fluorine has a normal boiling point of 85 K, and chlorine boils at 239 K. The Cl2 molecule is much larger than F2 (atomic radius is 99 pm for chlorine and is 64 pm for fluorine). Which is the best reason for the large difference in boiling points?<n>A.Chlorine has a higher dipole moment than fluorine.<n>B.The intramolecular bonds in Cl2 are much weaker than those in F2.<n>C.The Cl2 electron clouds are much more polarizable than the F2 electron clouds, resulting in much stronger London forces.<n>D.The mass of chlorine is much greater than the mass of fluorine.[SEP]C
Less than 1/1000 of the mass of any atom is contributed by<n>A.the electrons<n>B.the electrons and neutrons<n>C.the electrons and protons<n>D.the protons and neutrons[SEP]A
What is the molecular mass of a gas that has a density of 2.05 g/L at 26.0 °C and 722 torr?<n>A.53.0 g/mol<n>B.46.7 g/mol<n>C.4.67 g/mol<n>D.2876 g/mol[SEP]A
Consider the Lewis structures for the following molecules: CO2, CO32-, NO2-, and NO3-. Which molecules are best represented by multiple resonance structures?<n>A.CO2 and CO32-<n>B.NO2- and NO3-<n>C.CO32- and NO3-<n>D.CO32-, NO2- and NO3-[SEP]D
Helium effuses through a pinhole 5.33 times faster than an unknown gas. That gas is most likely<n>A.CO2<n>B.CH4<n>C.C5H12<n>D.C8H18[SEP]D
When a solid melts, the entropy change and enthalpy changes expected are<n>A.positive enthalpy change and positive entropy change<n>B.negative entropy change and a negative enthalpy change<n>C.negative entropy change and positive enthalpy change<n>D.negative enthalpy change and positive entropy change[SEP]A
If 1.0 g of rubidium and 1.0 g of bromine are reacted, what will be left in measurable amounts (more than 0.10 mg) in the reaction vessel?<n>A.RbBr only<n>B.RbBr and Rb only<n>C.RbBr and Br2 only<n>D.RbBr, Rb, and Br2[SEP]C
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?<n>A.186 pm, 496 kJ/mol<n>B.186 pm, 898 kJ/mol<n>C.135 pm, 523 kJ/mol<n>D.147 pm, 523 kJ/mol[SEP]A
Carbon exists in various forms called allotropes. Which of the following is not an allotrope of carbon?<n>A.diamond<n>B.soot<n>C.buckminsterfullerene<n>D.graphite[SEP]B
Based on periodic relationships, the concepts related to bond strength, and the concept relating bond strength to acid strength, which of the following correctly predicts the strength of binary acids from strongest to weakest?<n>A.H2Se > H2O > H2S<n>B.H2S > H2Se > H2O<n>C.H2O < H2S < H2Se<n>D.H2Se > H2S > H2O[SEP]D
Which of the following is considered a metalloid?<n>A.Cr<n>B.Mn<n>C.Si<n>D.S[SEP]C
S(s) + O2(g) → SO2(g)<n>A.one atom of S reacts with one molecule of O2 to yield one molecule of SO2<n>B.one mole of sulfur atoms reacts with one mole of oxygen molecules to yield one mole of sulfur dioxide molecules<n>C.the position of equilibrium must be on the product side<n>D.the entropy increase will be large[SEP]D
Which of the following is expected to have the highest electronegativity?<n>A.S<n>B.Fe<n>C.W<n>D.Ag[SEP]A
What is the pH of a solution made by dissolving 0.0300 mol of sodium ethanoate in enough water to make 50 mL of solution (Ka for ethanoic acid is 1.8 × 10^-5)?<n>A.7<n>B.9.26<n>C.4.74<n>D.11.02[SEP]B
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?<n>A.0.0500 g<n>B.0.0250 g<n>C.0.0125 g<n>D.0.00625 g[SEP]C
The molar heat of vaporization of water is +43.9 kJ. What is the entropy change for the vaporization of water?<n>A.8.49 J mol-1 K-1<n>B.4.184 J mol-1 K-1<n>C.2.78 J mol-1 K-1<n>D.118 J mol-1 K-1[SEP]D
A metal is reacted with HCl to produce hydrogen gas. If 0.0623 gram of metal produces 28.3 mL of hydrogen at STP, the mass of the metal that reacts with one mole of hydrochloric acid is<n>A.98.6 g<n>B.493 g<n>C.24.7 g<n>D.49.3 g[SEP]C
The rate of a chemical reaction is determined by<n>A.the equilibrium constant<n>B.the rate-determining or slow step of the mechanism<n>C.the reaction vessel pressure<n>D.the intermediates formed in the first step[SEP]B
A first-order reaction has a half-life of 34 minutes. What is the rate constant for this reaction?<n>A.3.4 × 10^-4 s-1<n>B.2.04 × 10^-2 s-1<n>C.2.9 × 10^-1 min-1<n>D.34 min[SEP]A
A certain reaction is nonspontaneous under standard conditions, but becomes spontaneous at higher temperatures. What conclusions may be drawn under standard conditions?<n>A.ΔH < 0, ΔS < 0 and ΔG = 0<n>B.ΔH > 0, ΔS < 0 and ΔG > 0<n>C.ΔH < 0, ΔS < 0 and ΔG > 0<n>D.ΔH > 0, ΔS > 0 and ΔG > 0[SEP]D
When collecting a gas over water, it is important to<n>A.set the temperature at 0°C<n>B.be sure the gas does not burn<n>C.wait until the barometer reads 760<n>D.correct for the vapor pressure of water[SEP]D
A sample of solid MgCl2 would be most soluble in which of the following solutions?<n>A.LiOH(aq)<n>B.CBr4(aq)<n>C.Mg(NO3)2(aq)<n>D.AlCl3(aq)[SEP]A
SO2Cl2 → SO2(g) + Cl2(g) At 600 K, SO2Cl2 will decompose to form sulfur dioxide and chlorine gas via the above equation. If the reaction is found to be first order overall, which of the following will cause an increase in the half life of SO2Cl2?<n>A.Increasing the initial concentration of SO2Cl2<n>B.Increasing the temperature at which the reaction occurs<n>C.Decreasing the overall pressure in the container<n>D.None of these will increase the half life[SEP]D
How many moles of propane (C3H8) are there in 6.2 g of propane?<n>A.14.1 mol<n>B.1.4 × 10^-1 mol<n>C.71 mol<n>D.7.1 mol[SEP]B
You cannot prepare a buffer by<n>A.mixing a solution of a weak base with a strong acid<n>B.mixing a solution of a weak acid with a strong base<n>C.mixing a solution of a strong base with a strong acid<n>D.mixing a solution of a weak acid with its conjugate base[SEP]C
Which would be the easiest way to burn a copper penny?<n>A.Hold the copper penny with crucible tongs, and heat strongly in the flame of a Bunsen burner.<n>B.Use the method in (A), but use an oxyacetylene torch to reach a higher temperature.<n>C.Grind the copper penny into very small, dust-sized particles, and spray the particles into a Bunsen burner flame.<n>D.Dissolve the copper penny in acid, precipitate the hydroxide, and heat in a Bunsen burner flame to make the oxide.[SEP]C
Which of the following molecules is a strong electrolyte when dissolved in water?<n>A.CH3COOH<n>B.HC2H3O2<n>C.PCl5<n>D.HBr[SEP]D
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?<n>A.HNO2<n>B.HClO4<n>C.H2S<n>D.H3PO4[SEP]B
The collision theory of reaction rates does not include<n>A.the number of collisions per second<n>B.the transition state<n>C.the energy of each collision<n>D.the orientation of each collision[SEP]B
When the dichromate ion is reacted, one of its most common products is Cr3+. What is the oxidation state (oxidation number) of chromium in the dichromate ion? Does reduction or oxidation occur when dichromate forms Cr3+?<n>A.3+, reduction<n>B.12+, reduction<n>C.6+, reduction<n>D.6+, oxidation[SEP]C
During the study of the reaction A → 2B, a chemist constructs several graphs. The graph of [A] versus time and the graph of ln [A] versus time both give a curved line; however, the graph of 1/[A] versus time and gives a straight line. This implies the rate law is<n>A.Rate = k[A]<n>B.Rate = k[A]^2<n>C.Rate = k[A]^0<n>D.Rate = k[A]^-1[SEP]B
