1 / 15

Redox Reactions

Redox Reactions. Many practical or everyday examples of redox reactions: Corrosion of iron (rust formation) Forest fire Charcoal grill Natural gas burning Batteries Metabolic processes. combustion. Redox Reactions. There are many different kinds of redox reactions. Combustion

sorena
Download Presentation

Redox Reactions

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. Redox Reactions • Many practical or everyday examples of redox reactions: • Corrosion of iron (rust formation) • Forest fire • Charcoal grill • Natural gas burning • Batteries • Metabolic processes combustion

  2. Redox Reactions • There are many different kinds of redox reactions. • Combustion CH4 (g) + 2 O2 (g)  CO2 (g) + 2 H2O (g) • Oxidation of Metals by Acids or Metal Salts Cu (s) + H2SO4(aq) CuSO4(aq) + H2(g)

  3. Redox ReactionsOxidation of Metals by Acids or Metal Salts • The reaction between a metal and an acid or between a metal and a metal salt is called a displacementreaction. • a reaction in which an element reacts with a compound and displaces an element from that compound A + BXAX +B

  4. Redox ReactionsOxidation of Metals by Acids or Metal Salts Examples: Mg(s) + 2HCl (aq)MgCl2(aq) + H2(g) Zn(s) + 2 HBr (aq)ZnBr2(aq) + H2(g) Mn (s) + Pb(NO3)2(aq)Mn(NO3)2(aq) + Pb (s)

  5. Redox ReactionsOxidation of Metals by Acids or Metal Salts • How do you know if a redox reaction has occurred? • You must examine the oxidation number of each of the elements present in the reactants and products. • If the oxidation number changes, then a redox reaction has occurred.

  6. Redox ReactionsOxidation of Metals by Acids or Metal Salts • When oxidation occurs: • Electrons are lost • Oxidation number increases • When reduction occurs: • Electrons are gained • Oxidation number is reduced (decreases)

  7. -1 -1 +1 +2 0 0 Oxidation # of Mg increased oxidation Oxidation # of H+ ion reduced reduction Redox ReactionsOxidation of Metals by Acids or Metal Salts Mg(s) + 2HCl (aq)  MgCl2 (aq) + H2 (g)

  8. Redox ReactionsOxidation of Metals by Acids or Metal Salts Example: Identify the element that has been oxidized and the one that has been reduced. Zn (s) + 2 HCl (aq) ZnCl2(aq) + H2(g)

  9. -1 -1 0 +2 0 +1 oxidized reduced Redox ReactionsOxidation of Metals by Acids or Metal Salts • To determine which components have been oxidized and reduced, find the oxidation numbers: Zn (s) + 2 HCl (aq) ZnCl2(aq) + H2(g)

  10. Redox ReactionsOxidation of Metals by Acids or Metal Salts • You can also write a net ionic equation to describe the reaction: • Write all soluble strong electrolytes as ions • Eliminate the spectator ions Zn (s) + 2 HCl (aq) ZnCl2(aq) + H2(g) Zn (s) + 2 H+(aq) + 2 Cl-(aq) Zn2+(aq) + 2 Cl-(aq) + H2(g) Zn (s) + 2H+ (aq) Zn2+ (aq) + H2(g)

  11. Redox ReactionsOxidation of Metals by Acids or Metal Salts Example: Write the complete ionic and net ionic equations for the reaction. Which element is oxidized? 2 Al (s) + 3 Ni(NO3)2(aq) 2 Al(NO3)3 (aq) + 3 Ni (s) 2 Al (s) + 3 Ni2+(aq) + 6 NO3- (aq) 2 Al3+ (aq) + 6 NO3-(aq) + 3 Ni (s) 2 Al (s) + 3 Ni 2+(aq)  2 Al3+ (aq) + 3 Ni (s)

  12. +5 +5 -2 oxidized Redox ReactionsOxidation of Metals by Acids or Metal Salts 2 Al (s) + 3 Ni(NO3)2(aq)2 Al(NO3)3 (aq) + 3 Ni (s) -2 0 +3 0 +2

  13. Redox ReactionsOxidation of Metals by Acids or Metal Salts • Based on the previous equation, we wouldn’t want to store a solution of Ni(NO3)3 in an aluminum container. • The aluminum container would react and dissolve!!! • Metals differ in the ease with which they are oxidized. • Al (s) is oxidized by Ni(NO3)3 (aq) • Ag(s) is NOT oxidized by Ni(NO3)3 (aq)

  14. Redox ReactionsOxidation of Metals by Acids or Metal Salts • Activity series: • A list of metals arranged in order of decreasing ease of oxidation • Used to predict whether a metal will react with an acid or with a metal salt • See table 4.5

  15. Activity Series

More Related