Chapter 06 - 4aa9fd21e9c2e8d9383448fd0ed97eca34429fd5.doc...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
4aa9fd21e9c2e8d9383448fd0ed97eca34429fd5.doc OXIDATION-REDUCTION REACTIONS Oxidation-reduction reactions describe chemical reactions in which transfer of electrons occurs from one substance to another. Oxidation implies reaction with oxygen Historically many of the first chemical reactions studied where those involving oxygen. Oxidation a substance loses electrons Reduction a substance gains electrons AZ Hint remember Leo! L ose E lectrons O xidation Oxidation-reduction always go together, ie you can’t have one without the other. If something is loses electrons, something is gaining those electrons. Some name calling Oxidation-reduction called redox reactions for short Substance that loses electrons Reducing Agent Substance that gains electrons Oxidizing Agent Some common examples of redox reactions - Combustion of fossil fuels - Metabolism of food - Reaction of oxygen with metals - Batteries - Cleaning products such as bleach - Atmospheric chemistry Chem 111 lecture notes page 1 by Alan Zombeck
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4aa9fd21e9c2e8d9383448fd0ed97eca34429fd5.doc We can write redox equations to show electron gain/loss Na Na + + e - Cl 2 + 2e - 2Cl - Example Calcium and oxygen react to form calcium oxide according to the following equation 2 Ca + O 2 2 CaO Which element is oxidized and which is reduced? What are the oxidizing and reducing agents? Ca Ca 2+ + 2e - Ca loses electrons therefore it was oxidized and is considered the reducing agent O 2 + 4e - 2O -2 O 2 gains electrons therefore it was reduced and is considered the oxidizing agent Note - just remember LEO to determine what was oxidized, identify that substance as the reducing agent. - Label the other substance as the opposite, i.e. what was reduced and the oxidizing agent examples oxidation of iron reduction of vanadium +3 ions by Zinc Oxidation Numbers Chem 111 lecture notes page 2 by Alan Zombeck
Background image of page 2
4aa9fd21e9c2e8d9383448fd0ed97eca34429fd5.doc Hopefully by now you realize that all ionization reactions are actually redox reactions. However, many redox reactions are not ionization reactions. In other words, we can have redox reactions in which electrons are gained/lost with molecular compounds. Thus, we need some way to keep track of how many electrons a substance is gaining or losing in a redox reaction. We do that by assigning oxidation numbers. Oxidation numbers are simply a “bookkeeping” system to determine whose losing and whose gaining electrons. Coming back to our example of NaCl,
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 17

Chapter 06 - 4aa9fd21e9c2e8d9383448fd0ed97eca34429fd5.doc...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online