Copper cell

Consider how these standard potentials are used to determine the voltage of an electric cell. In the zinc-copper cell described earlier, the two halfreactions must be added to determine the cell EMF. (See Table 12-2.)... 

The complete zinc-copper cell has a total potential of 1.10 volts (the sum of 0.76v and 0.34v). Notice that the sign of the potential of the zinc anode is the reverse of the sign given in the chart of standard electrode potentials (see Table 12-4) because the reaction at the anode is oxidation. 

In the chart of standard electrode potentials (Table 12-1), reactions are arranged in order of their tendency to occur. Reactions with a positive EMF occur more readily than those with a negative EMF. The zinc-copper cell has an overall EMF of + 1.10 volts, so the solution of zinc and deposition of copper can proceed. 

The best exanple of this problem is the cell house operations. Similar copper cell houses of much greater size can be found in every major copper or zinc refinery in the world. The technical challenge far REOCNTEK was to reduce the scale of that technology to the appropriate size for the waste recycling industry without major losses in electrical or manpower efficiencies. 

The activity series shows that zinc is a better loser of electrons than copper. It is this relative difference in the two metals that causes zinc to be the electron loser in the zinc/copper cell. Zinc responds differently when paired with a metal higher that it is in the activity series. 

The ion entrance plate ( 0.1 mm thick) with a small hole (typically 0.5 mm diameter) has the same electric potential as the copper cell, whereas the exit plate (same dimensions) is mounted to a cell end cap that is electrically isolated from the cell body by a ceramic ring. The end cap has its own cooling and heating systems. 

Practice Problem 1 7.4 Calculate the potential of a lead/copper cell in which the lead electrode is immersed in a 0.100 M lead(II) nitrate and the copper electrode is immersed in 0.200 M copper(ll) sulfate. Determine which metal is reduced spontaneously. ... 

Which of the following is true of the tin/copper cell reaction ... 

The Zinc-Copper Cell 21-10 The Copper-Silver Cell... 

Left) A strip of zinc was placed in a blue solution of copper(II) sulfate, CUSO4. The copper has been displaced from solution and has fallen to the bottom of the beaker. The resulting zinc sulfate solution is colorless. This is the same overall reaction as the one that occurs when the two half-reactions are separated in the zinc-copper cell (see Figure 21 -6). (Right) No reaction occurs when copper wire is placed in a colorless zinc sulfate solution. The reaction... 

Voltaic cells can be represented as follows for the zinc-copper cell. 

Recall that in the zinc-copper cell the copper electrode is the cathode now in the copper-silver cell the copper electrode is the anode. 

A zinc-copper cell like that shown in Figure 21-7 is constructed, except that an inert platinum wire is used instead of the salt bridge. Will the cell still produce a potential ... 

Figure 15. Bismuth-Telluride Thermopile, 21, mounted in a heat conduction calorimeter. 13, the leads 18, the heater 20, the copper cell holder 19, the cell and 22, the entrance channel.

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