The overall cell reaction occurring in an alkaline battery is Zn(s) + MnO2(s) + H2O(l) → ZnO(s) + Mn(OH)2(s) (a) How many moles of electrons flow per mole of reaction? (b) If 4.50 g of zinc is oxidized, how many grams of manganese dioxide and of water are consumed? (c) What is the total mass of reactants consumed in part (b)?

An electrolytic cell is set up with Cd(s) in Cd(NO3)2(aq) and Zn(s) in Zn(NO3)2(aq). Initially both electrodesweigh 5.00 g. After running the cell for several hours theelectrode in the left compartment weighs 4.75 g. (a) Which electrode is in the left compartment? (b) Does the mass of the electrode in the right compartmentincrease, decrease, or stay the same? If the masschanges, what is the new mass? (c) Does the volume of the electrode in the right compartment increase, decrease, or stay the same? If the volumechanges, what is the new volume? (The density of Cd is8.65 g/cm3.)

A solution contains the ions H+, Ag+, Pb2+, and Ba2+, each at a concentration of 1.0 M. (a) Which of these ions would be reduced first at the cathode during an electrolysis? (b) After the first ion has been completely removed by electrolysis, which is the second ion to be reduced? (c) Which, if any, of these ions cannot be reduced by the electrolysis of the aqueous solution?

The following two half-reactions arc involved in a voltaic cell. At standard conditions, what species is produced at each electrode? Ag++eAgE=0.80VNi2++2eNiE=0.25V

Use the data from the table of standard reduction potentials in Appendix H to calculate the standard potential of the cell based on each of the following reactions. In each case, state whether the reaction proceeds spontaneously as written or spontaneously in the reverse direction under standard-state conditions. (a) H2(g)+Cl2(g)2H+(aq)+2Cl(aq) (b) Al3+(aq)+3Cr2+(aq)Al(s)+3Cr3+(aq) (c) Fe2+(aq)+Ag+(aq)Fe3+(aq)+Ag(s)

The mass of three different metal electrodes, each from a different galvanic cell, were determined before and after the current generated by the oxidation-reduction reaction in each cell was allowed to flow for a few minutes. The first metal electrode, given the label A, was found to have increased in mass; the second metal electrode, given the label B, did not change in mass; and the third metal electrode, given the label C, was found to have lost mass. Make an educated guess as to which electrodes were active and which were inert electrodes, and which were anode(s) and which were the cathode(s).

An aqueous solution of an unknown salt of gold is electrolyzed by a current of 2.75 amps for 3.39 hours. The electroplating is carried out with an efficiency of 93.0%, resulting in a deposit of 21.221 g of gold. a How many faradays are required to deposit the gold? b What is the charge on the gold ions (based on your calculations)?

A solution of copper(II) sulfate is electrolyzed by passing a current through the solution using inert electrodes. Consequently, there is a decrease in the Cu2+ concentration and an increase in the hydronium ion concentration. Also, one electrode increases in mass and a gas evolves at the other electrode. Write half-reactions that occur at the anode and at the cathode.

Consider the following galvanic cell: What happens to as the concentration of Zn2+ is increased? As the concentration of Ag+ is increased? What happens to in these cases?

. In which direction do electrons flow in a galvanic cell, from anode to cathode or vice versa?