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Electrochemistry question? (Voltaic Cell) | Socratic

source : socratic.org

Electrochemistry question? (Voltaic Cell) | Socratic

This is a Galvanic cell. Galvanic cells are spontaneous meaning they have a #-DeltaG^@#. A #-DeltaG^@# just means the reaction occurs without the input of any outside energy source, under standard conditions that is. The standard cell potential of the cell, #E^@#, is always positive in a galvanic cell. Basically, Gibbs and Standard Cell Potential have opposite signs.

You have solid #”Cu”# and #”Zn”# in their respective half cells. Looking at the standard reduction potentials provided, the more positive value means the more likely that species is going to be reduced. A quick look at the table will show you that #”Cu”^(+2)# ions will readily reduce to form solid #”Cu”# than #”Zn”^(+2)# ions will to become #”Zn”# solid.

#color(white)(aaaa)color(magenta)[“Cu”^(+2)(aq) + 2e^(-) ->”Cu”(s) color(white)(aaaaa)”E”^@(“red”) = +0.34]##(“more positive red. potential means reduction will occur”)#

#color(white)(aaaa)color(green)[“Zn”^(+2)(aq) + 2e^(-)->”Zn”(s) color(white)(aaaaa)”E”^@(“red”) = -0.76]##(“less positive red. potential means oxidation occurs”)#

#color(white)(aaaaaaaaaaaaaaaa)##——————-#

#color(blue)(“A: Which electrode is the cathode in the reaction above?”)#

Since we know that#”Cu”^(+2)# ions are more likely to be reduced to become #”Cu”(s)#, the #color(red)(“Cu electrode is labeled as the cathode”)# while the #color(red)(“Zn electrode is labeled as the anode”)#, where oxidation occurs. (remember the memory aid AN OX, RED CAT)

#color(blue)(“B: Give the half reaction occurring at each of the electrodes below.”)#

#color(blue)(“Make sure it shows the direction the reaction actually proceeds in the”)##color(blue)(“cell above.”)#

If reduction is occurring at the #”Cu”# cathode (where we know the solution of #”Cu(NO3)”_2# ionizes to give off #”Cu”^(+2)# cations and #”NO”_3^(-1)# anions), this means #”Cu”^(+2)# ions will gain #2e^-# and will deposit onto the #”Cu”# electrode. The half reaction is the following for the left half cell:

#color(white)(aaaaaaaaaaaa)color(red)[“Cu”^(+2)(aq) + 2e^(-) ->”Cu”(s)#

#color(white)(aaaaaaaaaaaa)#

In the right half cell, the #”Zn”# electrode (which is the anode) will lose #2e^-# and #”Zn”^(+2)# ions will fall out into the solution which already has #”Zn”^(+2)# cations and #”NO”_3^(-1)# ions from the zinc nitrate solution. The half reaction in the right cell is the following:

#color(white)(aaaaaaaaaaa)color(red)[“Zn”(s)-> “Zn”^(+2)(aq) + 2e^(-)#

#color(blue)(“C: Write a balanced chemical equation describing the total reaction of the”)##color(blue)(“electrochemical cell.”)#

If we combine the two half reactions, we get

#”Cu”^(+2)(aq) + cancel(2e^(-)) ->”Cu”(s)##”Zn”(s)-> “Zn”^(+2)(aq) + cancel(2e^(-))##————–##color(red)[“Cu”^(+2)(aq) + “Zn”(s)->”Cu”(s) + “Zn”^(+2)(aq)#

#color(blue)(“D: What is the EMF of the cell above(under standard state conditions)”)#

Okay. We have established that at the #”Cu”# half cell, reduction will occur and at the #”Zn”# half cell. oxidation will occur. To find the EMF of the cell, the following equation is going to be used.

#color(white)(aaaaaaa)”E”^@(“cell”) = “E”^@(“red”) + “E”^@(“oxidation”)#

Since we were provided #”E”^@(“red”)# potentials, we have to reverse the reaction to show the oxidation of #”Zn”(s)# as well as reversing the value of the standard reduction potential to get the standard oxidation potential.

#”Cu”^(+2)(aq) + 2e^(-) ->”Cu”(s)color(white)(aaaaa)”E”^@(“red”) = +0.34#

#”Zn”(s)->”Zn”^(+2)(aq) + 2e^(-)color(white)(aaaaa)”E”^@(“oxidation”) = +0.76##color(white)(aaaaa)#- Use the equation to plug in and solve:

#color(white)(aaaaa)”E”^@(“cell”) = “E”^@(“red”) + “E”^@(“oxidation”)#

#color(white)(aaaaa)color(red)[“E”^@(“cell”) = (+0.34) + (+0.76) = +1.1#

Cell Potential - an overview | ScienceDirect Topics

Cell Potential – an overview | ScienceDirect Topics – The standard cell potentials, which were discussed above, refer to cells in which all dissolved substances For example, the standard indicates that values below − 350 mV have a 90% probability of Because the actual cell potential E is compared with the maximum possible cell potential Er…Galvanic Cell (or Voltaic Cell) is a type of electrochemical cell1 that converts chemical energy of oxidants and reductants into electrical energy. E0(cell), is referred to as the standard cell's potential difference or the cell's electromotive force (emf), and is the maximum voltage that can be produced…Design Introduction Voltaic cells are electrochemical cells that use a reduction reaction to produce electrical copper metal electrode. The reaction that occurs during a voltaic cell is as follows: The half reaction Raw Data Table 1: Cell potential/ voltage potential (V) produced from 0.1 mol/dm3…

Galvanic Cells or Voltaic Cells Chemistry Tutorial – Use the half-reactions below to produce a voltaic cell with the given standard cell potential. Selective Reduction The standard reduction potential for the half-reaction: Sn4+ + 2e – Sn2+ is +0.15 V. Consider data from the table of standard reduction potentials for common half-reactions, in your…Use standard reduction potentials to calculate the total potential of a given electrochemical cell. electrical potential: A measurement of the ability of a voltaic cell to produce an electric current; typically cell potential: The difference in standard reduction potentials between the two half-cells…The values below are standard reduction potentials for half-reactions measured at 25°C, 1 atmosphere and a pH of 7 in aqueous solution. The actual physiological potential depends on the ratio of the oxidized and reduced form according to the Nernst equation and the thermal voltage. .

Galvanic Cells or Voltaic Cells Chemistry Tutorial

Chemistry Voltaic Cell IA | Anode | Redox – Nonstandard Cell Potential Using Reaction Quotient Q 7. Calculating The Product Reactant Ratio Using The Cell Potential 8. The Purpose of Salt Bridge Electrochemistry Stoichiometry Problems 18. How To Calculate the Current in Amps Given the mass in grams and the time in minutes 19.Standard Electrode Potentials. In an electrochemical cell When an electrochemical cell is arranged with the two half-reactions separated but connected by an The Nernst Equation. The cell potential for a voltaic cell under standard conditions can be calculated from the standard electrode potentials.(e) All voltaic (galvanic) cells involve the use of electricity to initiate nonspontaneous chemical The half-reaction that occurs at the anode during the electrolysis of molten sodium bromide is As the cell given below operates, the strip of silver gains mass (only silver) and the concentration of silver…

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