1.which polyatomic ion has a charge of 3–? 7.which .... murdoch unit 12 question bank reg chem...

Mr. Murdoch Unit 12 Question Bank Reg Chem '14 to '15

'08 to '12 Regents Exams Only NYS Regents

1) chromate ion 2) oxalate ion3) phosphate ion 4) thiocyanate ion

1. Which polyatomic ion has a charge of 3–?

1) sharing of electrons2) sharing of protons3) transfer of electrons4) transfer of protons

2. An oxidation-reduction reaction involves the

1) Zn2+ 2) Mg2+

3) Co2+ 4) Ca2+

3. Which ion is most easily reduced?

1) Al Al3+ + 3e–

2) Al3+ + 3e– Al3) Cu Cu2+ + 2e–

4) Cu2+ + 2e– Cu

4. Given the balanced ionic equation representing areaction:

2Al(s) + 3Cu2+(aq) 2Al3+(aq) + 3Cu(s)Which half-reaction represents the reductionthat occurs?

1) Fe2+ ®Fe3+ + e–

2) Fe2+ + 2e– ® Fe3) Fe3+ + e– ® Fe2+

4) Fe ® Fe2+ + 2e–

5. Which half-reaction equation represents thereduction of an iron(II) ion?

1) K+ + e– ® K 2) K + e– ® K+

3) K+ ® K + e– 4) K ® K+ + e–

6. Which half-reaction equation represents thereduction of a potassium ion?

1)2)3)4)

7. Which equation represents anoxidation-reduction reaction?

1) Ba(NO3)2 + Na2SO4 ®BaSO4 + 2NaNO3

2) H3PO4 + 3KOH ®K3PO4 + 3H2O3) Fe(s) + S(s) ®FeS(s)4) NH3(g) + HCl(g) ®NH4Cl(s)

8. Which balanced equation represents anoxidation-reduction reaction?

1) AgNO3(aq) + NaCI(aq) ® AgCI(s) +NaNO3(aq)

2) H2CO3(aq) ® H2O( ) + CO2(g)3) NaOH(aq) + HCl(aq) ® NaCl(aq) + H2O(

)4) Mg(s) + 2HCl(aq) ® MgCl2(aq) + H2(g)

9. Which balanced equation represents a redoxreaction?

1) Ag 2) Au 3) Cu 4) Pb

10. Which metal is more active than H2?

1) –1 2) +2 3) –3 4) +4

11. What is the oxidation state of nitrogen in thecompound NH4Br?

1) –1 2) +2 3) +6 4) +4

12. What is the oxidation number of sulfur in Na2S2O3 ?

1) –1 to +1 2) –1 to +53) + l to –1 4) +5 to –1

13. Given the balanced equation representing areaction:

2KClO3(s) 2KCl(s) + 3O2(g)The oxidation state of chlorine in this reactionchanges from



1) transmutation 2) reduction3) oxidation 4) neutralization

14. During which process does an atom gain oneor more electrons?

1) Mn4+ ® Mn3+ + e–

2) Mn4+ ® Mn7+ + 3e–

3) Mn4+ + e– ® Mn3+

4) Mn4+ + 3e– ® Mn7+

15. Which half-reaction correctly representsreduction?

1) less than the total number of electronsgained

2) greater than the total number of electronsgained

3) equal to the total number of electronsgained

4) equal to the total number of protons gained

16. In a redox reaction, the total number ofelectrons lost is

1) +2 to 0 as electrons are transferred2) +2 to 0 as protons are transferred3) +3 to 0 as electrons are transferred4) +3 to 0 as protons are transferred


Fe2O3 + 2Al Al2O3 + 2FeDuring this reaction, the oxidation number ofFe changes from

1)2)3)4)

18. Which balanced equation represents a redoxreaction?

1) CH4 + 2O2 CO2 + 2H2O2) H2SO4 + Ca(OH)2 CaSO4 + 2H2O3) MgCrO4 + BaCl2 MgCl2 + BaCrO4

4) Zn(NO3)2 + Na2CO3 2NaNO3 + ZnCO3

19. Which equation represents an oxidation-reduction reaction?

1) Cl2(g) + 2NaBr(aq) Br2( ) + 2NaCl(aq)2) Cl2(g) + 2NaF(aq) F2(g) + 2NaCl(aq)3) I2(s) + 2NaBr(aq) Br2( ) + 2NaI(aq)4) I2(s) + 2NaF(aq) F2(g) + 2NaI(aq)

20. Which reaction occurs spontaneously?

1) Cu 2) Cr 3) Mg 4) Pb

21. Which metal is more active than Ni and less active than Zn?

1) Fe3+ + Al Fe2+ + Al3+

2) Fe3+ + 3Al Fe2+ + 3Al3+

3) 3Fe3+ + Al 3Fe2+ + Al3+

4) 3Fe3+ + Al Fe 2+ + 3Al3+

22. Which ionic equation is balanced?

1) 12 moles 2) 2 moles3) 3 moles 4) 6 moles


2Fe + 3Cu2+ ® 2Fe3+ + 3Cu

When the iron atoms lose six moles ofelectrons, how many moles of electrons aregained by the copper ions?



1) Oxidation and reduction both occur at theanode.

2) Oxidation and reduction both occur at thecathode.

3) Oxidation occurs at the anode, andreduction occurs at the cathode.

4) Oxidation occurs at the cathode, andreduction occurs at the anode.

24. Which statement describes where the oxidationand reduction half-reactions occur in anoperating electrochemical cell?

1) chemical to electrical2) electrical to chemical3) chemical to nuclear4) nuclear to chemical

25. Which energy change occurs in an operatingvoltaic cell?

1) electrical energy2) geothermal energy3) mechanical energy4) nuclear energy

26. A voltaic cell spontaneously converts chemicalenergy to

1) chemical energy to electrical energy2) chemical energy to nuclear energy3) electrical energy to chemical energy4) nuclear energy to electrical energy

27. Which energy conversion occurs in a voltaiccell?

1) anode 2) cathode3) salt bridge 4) external circuit

28. When a voltaic cell operates, ions movethrough the

1) Cu anode to the Zn cathode2) Cu cathode to the Zn anode3) Zn anode to the Cu cathode4) Zn cathode to the Cu anode

29. Given the balanced ionic equation representingthe reaction in an operating voltaic cell: Zn(s) + Cu2+(aq) ® Zn2+(aq) + Cu(s)

The flow of electrons through the externalcircuit in this cell is from the

1) electrolytic cells, only2) voltaic cells, only3) both electrolytic cells and voltaic cells4) neither electrolytic cells nor voltaic cells

30. Reduction occurs at the cathode in

1) combustion 2) neutralization3) oxidation 4) reduction

31. Which reaction occurs at the cathode in anelectrochemical cell?

1) chemical energy to electrical energy2) electrical energy to chemical energy3) nuclear energy to thermal energy4) thermal energy to nuclear energy

32. Which energy conversion occurs in anoperating electrolytic cell?

1) It produces electrical energy.2) It requires an external energy source.3) It uses radioactive nuclides.4) It undergoes a spontaneous redox reaction.

33. Which statement describes one characteristicof an operating electrolytic cell?



1) Electrons flow through the salt bridgefrom the Ni(s) to the Zn(s).

2) Electrons flow through the salt bridgefrom the Zn(s) to the Ni(s).

3) Electrons flow through the wire from theNi(s) to the Zn(s).

4) Electrons flow through the wire from theZn(s) to the Ni(s).

34. The diagram below represents an operatingelectrochemical cell and the balanced ionicequation for the reaction occurring in the cell.

Which statement identifies the part of the cellthat conducts electrons and describes thedirection of electron flow as the cell operates?

1) Chemical energy is used to produce anelectrical change.

2) Chemical energy is used to produce athermal change.

3) Electrical energy is used to produce achemical change.

4) Thermal energy is used to produce achemical change.

35. Which statement describes electrolysis?

1) at the anode, where oxidation occurs2) at the anode, where reduction occurs3) at the cathode, where oxidation occurs4) at the cathode, where reduction occurs

36. Given the balanced equation representing areaction occurring in an electrolytic cell:

2NaCl( ) 2Na( ) + Cl2(g)Where is Na( ) produced in the cell?



Base your answers to questions 37 through 40 on the information below.

A student constructs an electrochemical cell during a laboratory investigation. Whenthe switch is closed, electrons flow through the external circuit. The diagram andequation below represent this cell and the reaction that occurs.

37. Write a balanced half-reaction equation for the oxidation that occurs when the switch isclosed.

38. Determine the number of moles of Al(s) needed to completely react with 9.0 moles of Ni 2+

(aq) ions.

39. State, in terms of energy, why this cell is a voltaic cell.

40. State the direction of electron flow through the wire when the switch is closed.




The diagram below represents an operating electrolytic cell used to platesilver onto a nickel key. As the cell operates, oxidation occurs at the silverelectrode and the mass of the silver electrode decreases.

41. Identify the cathode in the cell.

42. State the purpose of the power source in the cell.

43. Explain, in terms of Ag atoms and Ag+(aq) ions, why the mass of the silver electrode decreases as the cell operates.



Base your answers to questions 44 and 45 on the information below.

The diagram and balanced ionic equation below represent a voltaic cell with copper andsilver electrodes and the reaction that occurs when the cell is operating.

44. Describe the direction of electron flow in the external circuit in this operating cell.

45. State the purpose of the salt bridge in this voltaic cell.

46. Explain, in terms of activity, why HCl(aq) reacts with Zn(s), but HCl(aq) does not reactwith Cu(s).




The diagram below represents an operatingvoltaic cell at 298 K and 1.0 atmosphere in alaboratory investigation. The reaction occurringin the cell is represented by the balanced ionicequation below.

47. Identify the anode in this cell.

48. Determine the total number of moles of Ni2+(aq) ions produced when 4.0 moles of Ag+(aq) ions completely react in this cell

49. Write a balanced half-reaction equation for thereduction that occurs in this cell.




In a laboratory investigation, a student constructs a voltaic cell with iron and copperelectrodes. Another student constructs a voltaic cell with zinc and iron electrodes. Testingthe cells during operation enables the students to write the balanced ionic equations below.

Cell with iron and copper electrodes: Cu2+(aq) + Fe(s) ® Cu(s) + Fe2+(aq)

Cell with zinc and iron electrodes: Fe2+(aq) + Zn(s) ® Fe(s) + Zn2+(aq)50. State evidence from the balanced equation for the cell with iron and copper electrodes that

indicates the reaction in the cell is an oxidation-reduction reaction.

51. Identify the particles transferred between Fe2+ and Zn during the reaction in the cell withzinc and iron electrodes.

52. Write a balanced half-reaction equation for the reduction that takes place in the cell withzinc and iron electrodes.

53. State the relative activity of the three metals used in these two voltaic cells.




A voltaic cell with magnesium and copper electrodes is shown in the diagram below.The copper electrode has a mass of 15.0 grams.

When the switch is closed, the reaction in the cell begins. The balanced ionicequation for the reaction in the cell is shown below the cell diagram. After several hours,the copper electrode is removed, rinsed with water, and dried. At this time, the mass ofthe copper electrode is greater than 15.0 grams.

54. State the directions of electron flow through the wire between the electrodes when theswitch is closed.

55. State the purpose of the salt bridge in this cell.

56. Explain, in terms of copper ions and copper atoms, why the mass of the copper electrodeincreases as the cell operates. Your response must include information about both copperions and copper atoms.



Base your answers to questions 57 and 58 on the information below.

Underground iron pipes in contact with moist soil are likely to corrode. This corrosioncan be prevented by applying the principles of electrochemistry. Connecting an iron pipe toa magnesium block with a wire creates an electrochemical cell. The magnesium block actsas the anode and the iron pipe acts as the cathode. A diagram of this system is shown below.

57. Explain, in terms of reactivity, why magnesium is preferred over zinc to protectunderground iron pipes. Your response must include both magnesium and zinc.

58. State the direction of the flow of electrons between the electrodes in this cell.

Base your answers to questions 59 and 60 on the following information.

A flashlight can be powered by a rechargeable nickel-cadmium battery. In the battery,the anode is Cd(s) and the cathode is NiO2(s). The unbalanced equation below representsthe reaction that occurs as the battery produces electricity When a nickel-cadmiumbattery is recharged, the reverse reaction occurs.

Cd(s) + NiO2(s) + H2O( ) ® Cd(OH)2(s) + Ni(OH)2(s)59. Explain why Cd would be above Ni if placed on Table J.



60. Determine the change in oxidation number for the element that makes up the anode in thereaction that produces electricity

1.which polyatomic ion has a charge of 3–? 7.which .... murdoch unit 12 question bank reg chem...

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