Electrochemistry Questions and Answers

I s Bi aq 3H O reduction 0 oxidation 21 aq BiO3 aq 6H aq 0 0

Write a balanced half reaction describing the oxidation of solid zinc to aqueous zinc cations 0 0

A galvanic cell is prepared based on a 8 electron process with E c cell 1 755 V At 25 C what is AGO for this reaction Please list your answer in units of kJ mol Write your answer with four significant figures

A galvanic cell is constructed by wiring a nickel electrode bathed in 1 0 M Ni with the two solutions ag to a lead electrode bathed in 1 0 M Pb connected by a salt bridge Consider the two half reactions listed below What is the cell voltage for this device Ni aq 2e Ni s E 0 26 V vs SHE Pb aq 2e Pb s E 0 13 V vs SHE Select one O a 0 13 V O b 0 39 V O c 0 39 V O d 0 20 V e 0 13 V

plate out from a Ni2 aq solution when 84 moles of electrons pass through the circuit 24 6 O 98 6 O 57 8 0 420 O 49 3 Reaction K eK s Ba2 2e Ba s Sr 2e Sr s Cat 2c Ca s Acian Na cNa s Mg 2e Mg s Al 3e Al s Mn2 2e Mn s Cr 2e Cr s Zn 2e Zn s Cr 3e Fe2 2e Cr Cd 2e Cr s Fe s Cr Cd s PbSO4 s 2e Pb s SO Co 2e Co s Ni 2e Ni s 2H 2e AgI s e Sn 2e Sn s Pb 2e Pb s Ag s I H g AgBr s e Ag s Br SnCl2 2e S s 2H 2e SnCl2 2 CI H S Ered 2 925 2 90 2 89 2 87 2 71 2 37 1 66 1 18 0 91 0 763 0 74 0 440 0 41 0 403 0 356 0 277 0 250 0 152 0 136 0 126 0 000 0 073 0 10 approxima 0 141 0 15

A voltaic cell is constructed using the following two cells and an NaCl salt bridge Half cell 1 Copper rod in copper II chloride solution Half cell 2 Aluminum rod in 0 360 M aluminum nitrate solution 3 50 M Cu aq 2e Cu s Al aq 3e Al s P 1 Write the net cell reaction for this cell 2 Write the complete abbreviated cell diagram for this cell You may use as vertical lines as needed 3 Determine E cell 4 Determine n 5 Determine Q 6 Determine Ecell 0 3419 v 1 676 v CuCh aa AI NO3 3 29

An electrochemical cell is prepared based on a 9 electron process with E cell 1 543 V At 25 C what is AGO for this reaction Please list your answer in units of kJ mol Write your answer with four significant figures

A galvanic voltaic cell has the generic metals X and Y as electrodes X is more reactive than Y that is X more readily reacts to form a cation than Y does Classify the descriptions by whether they apply to the X or Y electrode anode X electrode electrons in the wire flow toward it Answer Bank electrons in the wire flow away from it X x aq wire cathode salt bridge Y electrode Y y2 aq

Calculate the standard potential E for this reaction from its AG value X s Y aq X aq Y s AG 33 0 kJ

Write the half reactions as they occur at each electrode and the net cell reaction for this electrochemical cell containing copper and silver Cu s Cu aq Ag aq Ag s anode cathode

Predict the standard potential for the galvanic cell Standard reduction potentials can be found in the standard reduction potentials table Ag s AgI s I aq Cl aq AgCl s Ag s

Constant pressure calorimetry is often done using a special type of calorimeter called bomb calorimeter True False

23 1 point The quantity of heat of a body of matter absorbs or releases when it experiences a temperature change of 1 kelvin is the heat capacity of the body of matter True False

In the following chemical reaction is the copper element oxidizing reactant or reducing reactant Cu 2 Ag www Cu 2Ag Both oxidizing and reducing reactant Reducing reactant Oxidizing reactant Neither oxidizing nor reducing reactant

Al A galvanic cell consists of an Ag s Ag aq half cell and a Zn s Zn aq half cell connected by a salt bridge Oxidation occurs in the zinc half cell The cell can be represented in standard notation as Zn s iZn2 aq Ag aq Ag s Ag s Ag aq Zn s Zn aq Zn2 aq iZn sAg s Ag aq Zn s Zn aq Ag s Ag aq Ag aq Ag s Zn s Zn aq

Write a balanced half reaction for the oxidation of solid manganese dioxide MnO to permanganate ion MnO4 in acidic aqueous solution Be sure to add physical state symbols where appropriate

4 points A galvanic cell is composed of these two half cells with the standard reduction potentials shown Co2 aq 2e Co s E 0 32 volt Cd2 aq 2e Cd s E 0 37 volt What is the standard free energy change in kJ for the cell reaction of this galvanic cell Report your answer in whole number Do not put unit in your answer

Which statement is true concerning a galvanic cell E for the cell is always negative The standard reduction potential for the anode reaction is always negative The standard reduction potential for the anode reaction is always positive E for the cell is always positive The standard reduction potential for the cathode reaction is always positive

The salt bridge in a galvanic cell allows the solutions in the half cells to remain electrically neutral by allowing the transfer of choose your answer between the half cells choose your answer solids points nsider these metal ion metal standard reduction potentials 2 aq Cd s 0 40 V Zn aq Zn s 0 76 V Ni aq Ni s 0 25 V Cu aq Cu s 0 34 V Co aq Co s 0 28 V ed on the data above which species is the best oxidizing agent Ni2 ions electrons electrolytes

a given galvanic cell the standard cell potential be calculated by subtracting the standard half potential of the reaction that occurs at the ode from the standard half cell potential of the ction that occurs at the anode Ered cathode Ered anode Tarnish on silver is the compound Ag2O A tarnished silver spoon is placed in an aluminum pan of boiling water Whe enough salt is added so that the solution conducts electricity the tarnish disappears Imagine that the two halves of this redox reaction were separated and connected with a wire and a salt bridge Part A Calculate the standard cell potential given the following standard reduction potentials Al 3e Al F 1 66 V Ag eAg E 0 799 V Express your answer to two decimal places and include the appropriate units View Available Hint s

The electrode for which the standard reduction potential of 0 00 V is assigned making it the electrode designated as the standard reference electrode uses the half reactics Ag ag c Ag s Cu aq 2c Cu s 2NH aq 2e H g 2NH3 e 2H aq 2e H s Zn aq 2e Zn s

When creating a tin coating for steel calculate the mass of Sn produced when a current of 5 0 A runs through a solution of tin IV nitrate for 90 minutes O a b O c d 132 0 g Sn 5 89 x 10 4 g Sn 0 332 g Sn 8 30 g Sn

True or False The reaction SO42 aq 4H aq 21 aq H SO3 aq 12 s H O 1 will occur spontaneously under standard state conditions Following are the standard reduction potentials that may be useful SO2 aq 2e 4H aq H SO3 aq H O 1 E 0 17 V 12 s 2e 21 aq E 0 54 V True False

duction potential for the cathode reaction is always positive 3 points The electrode for which the standard reduction potential of 0 00 V is assigned making it the electrode designated as the standard reference electrode uses the half reaction 2H aq 2e H g Ag aq eAg s 2NH4 aq 2e H g 2NH3 g Cu aq 2e Cu s Zn2 aq 2e Zn s

To create a gold plating for copper metal calculate the mass of Au produced when a current of 2 0 A runs through a solution of gold III nitrate for 60 minutes a b c d 44 1 g Au 0 082 g Au 4 90 g Au 1 22 g Au

4 points Using the standard reduction potentials Au aq 3e Au s 1 44volt Ca2 aq 2e Ca s 2 73 volt Calculate the value of E cell in volt for the cell reaction 2Au s 3Ca aq 2Au aq 3Ca s Report your answer with 2 places past the decimal place Do not report unit your answer

A bureaucracy is the most cost effective way to organize A bureaucracy is the most effective way for people to work on large and complex tasks

3 points Consider these metal ion metal standard reduction potentials Cu aq Cu s 0 34 V Ag aq Ag s 0 80 V Co2 aq Co s 0 28 V Zn aq Zn s 0 76 Based on the data above which one of the species below is the best reducing agent Zn s Cu s Ag s Cu aq

A galvanic cell is composed of these two half cells with the standard reduction potentials shown Co2 aq 2e Co s 0 33 volt Cd2 aq 2e Cd s 0 44 volt The actual concentrations are Co2 aq 0 0006 M Cd2 0 094 M What is the potential in volt of this galvanic cell T 298K Report your answer with 3 places past the decimal point Do not put unit in your answer Type your answer

A galvanic cell at a temperature of 25 0 C is powered by the following redox reaction 2V0 aq 4H aq Fe s 2V0 aq 2H 0 Fe aq Suppose the cell is prepared with 6 15 M VO and 1 34 M H in one half cell and 2 39 M VO and 4 84 M Fe in the other Calculate the cell voltage under these conditions Round your answer to 3 significant digits D D D H DC

Part A Balancing Redox Equations in Basic So If you complete and balance the following oxidation reduction reaction in basic solution NO aq Al s NH3 aq Al OH 4 aq how many hydroxide ions are there in the balanced equation for the reaction balanced with the smallest whole number coefficients One on the reactant side One on the product side Four on the reactant side Seven on the product side None

taic cell is constructed with two Zn Zn rodes The two cell compartments have 2 0 M and Zn 1 70x10 2M ectively Part B What is the standard emf of the cell Submit Part C VAE Request Answer What is the cell emf for the concentrations given Express your answer using two significant figures V

If you complete and balance the following equation in acidic solution Mn aq NaBiO3 s Bi aq MnO4 aq Na aq how many water molecules are there in the balanced equation for the reaction balanced with the smallest whole number coefficients 00 Two on the product side Four on the reactant side Three on the product side One on the reactant side Seven on the product side Submit Request Answer

4 points Using these metal ion metal standard reduction potentials Cd2 aq Cd s 0 36 V Zn2 aq Zn s 0 75V Ni2 aq Ni s 0 27V Cu2 aq Cu s 0 38 V Calculate the standard cell potential in V for the cell reaction Cu2 aq Cd s Cd aq Cu s Report your answer with 2 places past the decimal point Do not put unit in your answer

Calculate the standard cell potential at 25 C for the reaction where AH 623 kJ and AS 141 J K Express your answer to three significant figures and include the appropriate units View Available Hint s E 0 3 45 HA X s 2Y aq X aq 2Y s V BYW

For a galvanic cell given the following half reactions and their standard reduction potentials 2CIO3 12H 10eCl 6H O E 1 51 volt S 08 2e2SO4 EO 2 04 volt Calculate the value of the equilibrium constant Kc Report your answer in scientific notation with 1 place past the decimal point Use this format 1 2 10 3 Type your answer

Consider these metal ion metal standard reduction potentials Cd2 aq Cd s 0 40 V Zn aq Zn s 0 76 V Ni aq Ni s 0 25 V Cu aq Cu s 0 34 V Co2 aq Co s 0 28 V Based on the data above which species is the best oxidizing agent Ni s Cu s Cd aq Zn aq Cu aq

Using the standard reduction potentials ant pried 210trotog AU aq 3e Au s 1 42 vol Ca aq 2e Ca s 2 80 Volt 00 60 Calculate the value of E cell in volt for the cell reactic 2Au s 3 Ca aq 2 AU aq 3Ca s D 05IDO

To learn how to use the Nernst equation The standard reduction potentials listed in any reference table are only valid at the common reference temperature of 25 C and standard conditions of 1 M for solutions and 1 atm for gases To calculate the cell potential at nonstandard conditions one uses the Nernst equation 2 303 RT nF E E Q where E is the potential in volts E is the standard potential at 25 C in volts R 8 314 J K mol is the gas constant T is the temperature in kelvins n is the number of moles of electrons transferred F 96 500 C male is the Faraday constant and Q is the reaction quotient log10 At the common reference temperture of 298 K substituting each constant into the equation the result is E E 0 0592 V n log10 Q Submit Completed Part D Part E Previous Answers What is the cell potential for the reaction Mg s Fe aq Mg2 aq Fe s at 55 C when Fe 2 90 M and Mg2 0 310 M Express your answer to three significant figures and include the appropriate units View Available Hint s HA

3 points Using the standard electrode potentials Cl g 2e 2Cl aq E 1 36 V E 0 40 V Cd aq 2e Cd s Al aq 3e Al s E 1 66 V Cu2 aq 2e Cu s E 0 34 V Decide which of the following reactions can happen spontaneously Cu2 oxidizes Cl Cd reduces Al Cd2 oxidizes Cu Cl oxidizes Cd

earning Goal o learn how to use the Nernst equation The standard reduction potentials listed in any eference table are only valid at the common eference temperature of 25 C and standard conditions of 1 M for solutions and 1 atm for gases To calculate the cell potential at honstandard conditions one uses the Nernst equation 2 303 RT n F E E log10 Q where E is the potential in volts E is the standard potential at 25 C in volts R 8 314 J K mol is the gas constant T is the temperature in kelvins n is the number of moles of electrons transferred F 96 500 C mol e is the Faraday constant and Q is the reaction quotient At the common reference temperture of 298 K substituting each constant into the equation the result is at 55 C where Fe2 2 90 M and Mg2 0 310 M Part A Part B Part C Mg s Fe aq Mg aq Fe s What is the value for n Express your answer as an integer and include the appropriate units i e enter mol for moles View Available Hint s A

Part A Calculating Ed from E red cell 0 07 V Given the standard reduction potential of Ni2 A voltaic cell based on the reaction 2 Eu aq Ni s 2 Eu aq Ni s generates Ecell Eu aq 0 28 V what is the standard reduction potential for the reaction Eu aq e Ered 0 35 V 0 35 V 0 21 V 0 21 V 0 07 V

Part A The standard cell potential E cell of the reaction below is 0 34 V The value of A Go for the reaction is Cu s 2H aq Cu aq H g 00001 0 34 66 130 130 none of the above kJ mol

quilibrium constant K for a redox reaction is d to the standard potential E by the on In K nFE RT en is the number of moles of electrons ferred F the Faraday constant is equal to 00 C mol e R the gas constant is al to 8 314 J mol K and T is the Kelvin berature Standard reduction potentials Part A E V 0 80 Express your answer numerically View Available Hint s Reduction half reaction Ag aq eAg s Cu2 aq 2e Cu s Sn aq 4e Sn s 2H aq 2e H g Ni2 aq 2e Ni s Fe aq 2e Fe s Zn aq 2e Zn s A1 aq 3e Al s 1 66 Mg2 aq 2e Mg s 2 37 0 34 0 15 0 0 26 0 45 0 76 Use the table of standard reduction potentials given above to calculate the equilibrium constant at standard temperature 25 C for the following reaction Fe s Ni2 aq Fe aq Ni s

equilibrium constant K for a redox reaction is ted to the standard potential E by the ation nFE In K RT ere n is the number of moles of electrons nsferred F the Faraday constant is equal to 500 C mol e R the gas constant is ual to 8 314 J mol K and T is the Kelvin mperature Part A Part B Ni aq 2e Ni s Fe aq 2e Fe s Calculate the standard cell potential E for the reaction WE Zn aq 2e Zn s A1 aq 3e Al s Mg2 aq 2e Mg s 0 26 0 45 0 76 if K 4 90 10 3 Express your answer to three significant figures and include the appropriate units View Available Hint s 1 66 2 37 X s Y aq X aq Y s

The equilibrium constant Kc was found to be 8 1 5 x 10 at 25 C for the following reaction 2 2X S 3Y aq 2x aq 3Y S What is the cell potential in volt for this read

A certain reaction has an E cell of 0 107 volts and has a AG of 30 9 kJ How many electrons are transferred in the reaction i moles of electrons are transferred in the reaction

Consider the following reaction at 298K Cd aq Pb s Cd s Pb aq Which of the following statements are correct Choose all that apply Odelta G 0 n 3 mol electrons E cell OK 1 cell 0

The system 2AgI Sn Sn 2Ag 21 has a calculated E cell 0 015 V What is the value of K for this system

Fe OH 2 s 2e Fe s 2OH aq E Fe OH 2 0 88 V NiO2 0 49 V Ni OH 2 s Fe OH 2 s NiO2 s Fe s 2H O NiO s Fe s 2H O Ni OH aq Fe OH 2 aq NiO2 s 2Fe s 2H O Ni OH 2 s 2Fe OH 2 s NiO2 s Fe s 2H O Ni OH 2 s Fe OH 2 s Hint X Incorrect