1 / 9

Chapter 15 Oxidation and Reduction

Chapter 15 Oxidation and Reduction. 15.5 Oxidation−Reduction Reactions that Require Electrical Energy Learning Goal Describe the half-cell reactions and the overall reactions that occur in electrolysis. Nonspontaneous Oxidation−Reduction Reactions.

nmathews
Télécharger la présentation

Chapter 15 Oxidation and Reduction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 15 Oxidation and Reduction 15.5 Oxidation−Reduction Reactionsthat Require Electrical Energy Learning Goal Describe the half-cellreactions and the overall reactionsthat occur in electrolysis.

  2. Nonspontaneous Oxidation−Reduction Reactions • In the activity series, the oxidation of copper is below zinc. This means the reaction is not spontaneous: Cu(s) + Zn2+(aq)  Cu2+(aq) + Zn(s) Not spontaneous • To make this reaction take place, we need an electrolytic cell that uses an electrical current to drive the nonspontaneous reaction.

  3. Nonspontaneous Oxidation−Reduction Reactions Figure 15.5 In this electrolytic cell, the Cu anode is in a Cu2+ solution, and the Zn cathode is in a Zn2+ solution. Electrons provided by a battery reduce Zn2+ to Zn and drive the oxidation of Cu to Cu2+ at the Cu anode.

  4. Electrolysis of Sodium Chloride When molten NaCl is electrolyzed, • the products are sodium metal and chlorine gas • electrodes are placed in a mixture of Na+ and Cl− and connected to a battery • the products are separated to prevent them from reacting with each other

  5. Electrolysis of Sodium Chloride When molten NaCl is electrolyzed, • electrodes leave the anode as Cl− is oxidizedto Cl2 2Cl−(l)  Cl2(g) + 2 e− • electrons flow to the cathode, Na+ is reduced to sodium metal, Na 2Na+(l) + 2 e− 2Na(l) • the overall reaction is 2Cl−(l) + 2Na+(l)  Cl2(g) + 2Na(l)

  6. Electroplating Electroplating uses electrolysis to coat an object with a thin layer of metal such as silver, platinum, or gold, for example • car bumpers and hubcaps are electroplated with chromium • bowls, silverware, and platters are electroplated with silver

  7. Electroplating Eating utensils are electroplated with silver.

  8. Learning Check What half-reaction takes place when Au3+ solution is used to gold plate a stainless steel earring?

  9. Solution What half-reaction takes place when Au3+ solution is used to gold plate a stainless steel earring? The half-reaction is reduction, Au3+(aq)  Au(s) + 3 e−

More Related