Regents Review Electrochemistry(redox) 2011-2012

Regents review Electrochemistry(redox)1. Chlorine has an oxidation state of 3 in the compoundA) HClOC) HClO 3B) HClO2D) HClO 42. What is the oxidation number of iodine in KIO 4?A) 1B) –1C) 7D) –73. What is the oxidation number of chromium in thechromate ion, CrO 42– ?A) 6B) 2C) 3D) 84. In which substance does phosphorus have a 3 oxidationstate?A) P4O10C) Ca3(PO4) 2B) PCl 5D) KH2PO 35. What is the oxidation number of oxygen in OF 2?A) 1B) 2C) –1D) –26. Given the lead-acid battery reaction:Pb PbO2 2 H2SO42 PbSO4 2 H2OWhich electronic equation represents the half-reactionfor the oxidation that occurs?A) PbPb2 2 e –C) Pb2 2 e –PbB) Pb4 4 e –Pb4 D) PbPb 4 e –7. Which particles are gained and lost during a redoxreaction?A) electronsC) neutronsB) protonsD) positrons8. When a redox reaction occurs, there must be a transfer ofA) electronsC) protonsB) neutronsD) ions9. Half-reactions can be written to represent allA)B)C)D)double-replacement reactionsneutralization reactionsfission and fusion reactionsoxidation and reduction reactions10. Which half-reaction correctly represents oxidation?A) Sn2 2e – Sn0C) Sn2 Sn0 2e –B) Sn4 2e – Sn2 D) Sn2 Sn4 2e –2011-201211. In a chemical reaction, as a species is oxidized, itsoxidation numberA) decreasesC) remains the sameB) increases12. In the reactionH3O OH– 2 H2O,the oxidation number of oxygenA) decreasesC) remains the sameB) increases

Regents review Electrochemistry(redox)13. Given the lead-acid battery reaction:When the reaction produces electricity, which element changes its oxidation state?A)B)C)14. During which process does an atom gain one or moreelectrons?A) transmutationC) oxidationB) reductionD) neutralization15. As a sodium atom is oxidized, the number of protons inits nucleusA) decreasesC) remains the sameB) increases16. Which half-reaction correctly represents reduction?A) Ag Ag e –C) Au 3 3e – AuB) F2 2 F– 2e –D) Fe 2 e – Fe 3 17. Given the balanced equation representing a redoxreaction:2Al 3Cu2 2Al3 3CuWhich statement is true about this reaction?A)B)C)D)Each Al loses 2e – and each Cu 2 gains 3e–.Each Al loses 3e– and each Cu 2 gains 2e–.Each Al3 gains 2e– and each Cu loses 3e –.Each Al3 gains 3e– and each Cu loses 2e –.18. Which half-reaction equation represents the reductionof an iron(II) ion?A) Fe 2 Fe 3 e –C) Fe 3 e – Fe 2 B) Fe2 2e – FeD) Fe Fe 2 2e –19. Which half-reaction equation represents the reductionof a potassium ion?A) K e – KC) K K e–B) K e– K D) K K e –D)20. Base your answer to the following question on thereaction below2 Cr(s) 3 Cu2 (aq) 2 Cr3 (aq) 3 Cu(s)The electronic equation that represents the oxidationreaction that occurs isA)B)C)D)2Cr0 – 6e – 2Cr3 2Cr 0 6e – 2Cr 3 2Cr 3 – 6e – 2Cr 02Cr 3 6e – 2Cr 021. Which equation represents an oxidation-reductionreaction?A)B)C)D)HCl KOH KCl H 2O4 HCl MnO 2 MnCl 2 2 H2O Cl 22 HCl CaCO3 CaCl2 H2O CO22 HCl FeS FeCl 2 H2S22. Which is a redox reaction?A)B)C)D)Mg 2 HCl MgCl 2 H2Mg(OH)2 2 HCl MgCl 2 2 H2OMg 2 (aq) 2 OH–(aq) Mg(OH)2MgCl 2 6 H2O MgCl 2 6 H 2O23. In which reaction are electrons transferred from onereactant to another reactant?A) 2Ca(s) O 2 (g) 2CaO(s)B) AgNO3 (aq) KCl(aq) AgCl(s) KNO 3 (aq)C) HCl(aq) NaOH(aq) NaCl(aq) H 2O( )D) H3O (aq) OH– (aq) 2H2O( )24. The reactionCuO CO CO2 Cuis an example ofA)B)C)D)reduction, onlyoxidation, onlyboth oxidation and reductionneither oxidation nor reduction

Regents review Electrochemistry(redox)25. Which balanced equation represents a redox reaction?A)B)C)D)AgNO3 NaCl AgCl NaNO 3BaCl2 K2CO 3 BaCO 3 2KClCuO CO Cu CO2HCl KOH KCl H 2O26. According to Reference Table J, which metal will reactwith Zn 2 but will not react with Mg2 ?35. Given the unbalanced equation:Ag2S 8HNO3AgNO3 2NO S H2OWhat is the coefficient of Ag2S when the equation iscompletely balanced using the smallest whole numbers?A) 6B) 2C) 3D) 436. Given the unbalanced equation:A) Al(s) B) Cu(s) C) Ni(s) D) Ba(s)27. According to Reference Table J, which of these metalswill react most readily with 1.0 M HCl to produce H 2(g)?A) CaB) KC) MgD) Zn28. According to Reference Table J, which species is thestrongest oxidizing agent?A) Li(s) B) Li C) F2(g) D) F–29. According to Reference Table J, which ion will oxidizeFe?A) Zn2 B) Ca2 C) Mg 2 D) Cu 2 30. Under standard conditions, which metal will react with0.1 M HCl to liberate hydrogen gas?A) AgB) AuC) CuD) Mg31. Which half-reaction for the reduction of Al 3 to Al iscorrectly balanced?A) Al 3 3e – AlC) Al 3 Al 3e –B) Al 3 3e – 3 AlD) Al 3 3 Al 3e –32. Which half-reaction shows both the conservation ofmass and the conservation of charge?A) Cl 2 2e – 2 Cl B) Cl 2 Cl – 2e –C) 2 Br – 2e – Br 2 D) Br – Br 2 2e –33. Which equation shows conservation of charge?A) Fe Fe 2 e –C) Fe Fe2 2e –B) Fe 2e – Fe 2 D) Fe 2e – Fe 3 34. Compared to the amount of mass and total charge at thebeginning of a redox reaction, the amount of mass andtotal charge upon completion of the reaction isA) lessC) the sameB) greaterMnO2 HCl MnCl2 H2O Cl2When the equation is correctly balanced using smallestwhole number coefficients, the coefficient of HCl isA) 1B) 2C) 3D) 437. Given the equation:3 Cu 8 HNO 3 3 Cu(NO 3) 2 2 NO 4 H2OWhat is the total number of moles of electronslost by the copper as it completely reacts with8 moles of nitric acid?A) 1B) 6C) 8D) 438. Given the balanced equation:2 Al(s) 6 H (aq) 2 Al3 (aq) 3 H2(g)When 2 moles of Al(s) completely reacts, what is thetotal number of moles of electrons transferred fromAl(s) to H (aq)?A) 5B) 6C) 3D) 439. When the equationAl 3 NO 3– H Al 3 3 H2O 3 NO2is completely balanced, the coefficient of Al will beA) 1B) 2C) 3D) 440. Given the equation:2 Al(s) 3 Cu2 (aq) 2 Al3 (aq) 3 Cu(s)The total number of moles of electrons transferred from2 Al(s) to Cu2 (aq) isA) 9B) 2C) 3D) 6

Regents review Electrochemistry(redox)41. Given the balanced equation representing a reaction:2Fe 3Cu2 2Fe 3 3Cu45. Base your answer to the following question on theequation and diagram below represent anelectrochemical cell at 298 K and 1 atmosphere.When the iron atoms lose six moles of electrons, howmany moles of electrons are gained by the copper ions?A) 12 molesC) 3 molesB) 2 molesD) 6 moles42. Given the balanced equation:3 Fe 3 (aq) Al(s) 3 Fe 2 (aq) Al 3 (aq)What is the total number of moles of electrons lost by 2moles of Al(s)?A) 1 moleC) 3 molesB) 6 molesD) 9 moles43. Given the reaction:HNO3 H3PO3 NO H3PO4 H2OWhen the reaction is completely balanced using thesmallest whole numbers, the coefficient of H3PO4 willbeA) 1B) 2C) 3D) 444. Given the equation:KMnO4 HCl KCl MnCl2 Cl2 H2OWhat is the coefficient of H2O when the equation iscorrectly balanced?A) 8B) 2C) 16D) 4Which species is oxidized when the switch is closed?A) Mg(s)C) Ag(s)B) Mg 2 (aq)D) Ag (aq)46. In a chemical cell composed of two half-cells, ions areallowed to flow from one half-cell to another by meansofA)B)C)D)electrodesa voltmeteran external conductora salt bridge47. The reaction that takes place in a chemical cell is bestclassified asA) fusionC) transmutationB) redoxD) cracking48. In a chemical cell, electrical energy will be producedwhenA)B)C)D)only oxidation occursonly reduction occursboth oxidation and reduction occurneither oxidation nor reduction occurs49. As an electrochemical cell approaches equilibrium, theelectrical energy supplied by the cellA) decreasesC) remains the sameB) increases

Regents review Electrochemistry(redox)50. Given the redox reaction:Which species is oxidized during discharge?A)C)B)D)51. Given the equation for the overall reaction in a lead-acid storage battery:Which occurs during the charging of the battery?A)B)C)D)The concentration ofThe concentration ofThe concentration ofThe concentration ofdecreases and the number of moles ofdecreases and the number of moles ofincreases and the number of moles ofincreases and the number of moles of52. Base your answer to the following question on thediagram of the chemical cell at 298 K and on theequation below.increases.increases.decreases.decreases.54. What occurs during discharge in the lead-acid batteryreaction below?Pb PbO 2 2 H2SO 4 « 2 PbSO 4 2 H2OA)B)C)D)Both Pb and Pb 4 undergo oxidation.Both Pb and Pb 4 undergo reduction.Pb is oxidized and Pb4 is reduced.Neither the Pb nor the Pb 4 is oxidized or reduced.55. The diagram below represents a chemical cell.In the given reaction, the Ag ionsA) gain electronsC) gain protonsB) lose electronsD) lose protons53. The electricity produced by a battery results fromA) an oxidation reaction, onlyB) a reduction reaction, onlyC) both an oxidation reaction and a reductionreactionD) neither an oxidation reaction nor a reductionreactionIn order for the cell to operate, it should be providedwithA)B)C)D)a cathodean anodea salt bridgean external path for electrons

Regents review Electrochemistry(redox)56. Which statement is true about oxidation and reductionin an electrochemical cell?A) Both occur at the anode.B) Both occur at the cathode.C) Oxidation occurs at the anode and reductionoccurs at the cathode.D) Oxidation occurs at the cathode and reductionoccurs at the anode.57. Given the balanced equation representing the reactionoccurring in a voltaic cell:Zn(s) Pb2 (aq)Zn2 (aq) Pb(s)In the completed external circuit, the electrons flowfromA)B)C)D)Pb(s) to Zn(s)Pb2 (aq) to Zn2 (aq)Zn(s) to Pb(s)Zn2 (aq) to Pb 2 (aq)58. Given the redox reaction:2 Cr(s) 3 Cu2 (aq) 2 Cr3 (aq) 3 Cu(s)Which reaction occurs at the cathode in anelectrochemical cell?A)B)C)D)reduction of Cu 2 (aq)reduction of Cu(s)oxidation of Cr3 (aq)oxidation of Cr(s)59. What occurs when an electrolytic cell is used forsilver-plating a spoon?A) A chemical reaction produces an electric current.B) An electric current produces a chemicalreaction.C) An oxidation reaction takes place at the cathode.D) A reduction reaction takes place at the anode.60. Base your answer to the following question on thediagram below of an electrolytic cell in which theelectrodes are tin and copper.In this electrolytic cell, electrode A is designated as theA)B)C)D)anode and is positiveanode and is negativecathode and is positivecathode and is negative

Regents review Electrochemistry(redox)61. Base your answer to the following question on the information below.Iron has been used for thousands of years. In the air, iron corrodes. One reaction forthe corrosion of iron is represented by the balanced equation below.Equation 1: 4Fe(s) 3O2(g) 2Fe2O3(s)In the presence of water, iron corrodes more quickly. This corrosion is represented by the unbalanceequation below.Equation 2: Fe(s) O2(g) H2O ( ) Fe(OH)2(s)Balance the equation below, using the smallest whole-number coefficients.Fe(s) O 2(g) H 2O( ) Fe(OH)2(s)Base your answers to questions 62 through 64 on the information below.Litharge, PbO, is an ore that can be roasted (heated) in the presence of carbon monoxide, CO, to produceelemental lead. The reaction that takes place during this roasting process is represented by the balancedequation below.PbO(s) CO(g) Pb( ) CO2(g)62. Calculate the percent composition by mass of oxygen in litharge (gram-formula mass 223.2 grams permole). Your response must include both a numerical setup and the calculated result.63. Determine the oxidation number of carbon in carbon monoxide.64. Write the balanced equation for the reduction half-reaction that occurs during this roasting process.