Textbook assignment: Read Kotz and Triechel, Chemistry and Chemical Reactivity Chapter 3: Sections 8 to 9.
3.8 Oxidation-Reduction Reactionsl. All oxidation-reduction reactions (redox reactions) involve electron transfers between the reactants to form the new components. While it may seem like the rules for redox reactions and assignment of oxidation numbers are somewhat arbitrary, they are based on the electron configuration and affinity characteristics of the atoms involved in the exchange.
3.9 Classifying Reactions. A reaction occuring in water-based solution is often classified as one (or more!) of four types: precipitation, salt-forming acid/base, gas-forming, or oxidation-reduction (electron transfer). Note the characteristics of each, and that a given reaction may fall into more than one classification category.
|X → Xn+ + n e-||X tranfers electrons to Y||X is oxidized and is the reducing agent|
|Y + ne- → Yn-||Y accelts electrons from X||Y is reduced and is the oxidizing agent|
|Atom or Molecule Type||Oxidation Number||Example|
|Atom in Pure Element||Zero||I2: each I = 0|
|Monatoic ion||Charge on ion||Mg2+: +2|
|Fluorine in copound||-1||FI: F is -1, I is therefore +1|
|Oxygen in compound||-2||H2O: O is -2, each H is +1|
EXCEPTIONS: in FO, O is +1
in perioxides, O is -1
in superioxides, O is -1/2
|Halogens Cl, Br, and I in compounds||-1||NaCl: Cl is -1; Na is therefore +1|
Exceptions: with O or F
ClO-: Cl is +1
|Hydrogen||+1||H2O: O is -2, each H is +1|
EXCEPTIONS: in metal hydrides, H is -1
CaH2: Ca is +2, each H is -1
|Neutrally charged compound||Sum of oxidation values is zero||H2O: 2 * -+1 + -2 = 0|
|Charged polyatomic ion||Sume of oxidation values equals charge||PO4-3-|
Each O: -2 total -8
Net: -8 + 5 = -3
Read the following weblecture before chat: Reduction-Oxidation (REDOX) Reactions
Review the Videos at Thinkwell Video Lessons under REACTIONS IN AQUEOUS SOLUTIONS.
Determination of water in copper sulfate pentahydrate and sodium hydrogen carbonate
What is the Amount of Water in Common Hydrates?
For this week: Decompose sodium hydrogen carbonate in a modified Solway process, calculating percent yield and percent atom economy.
© 2005 - 2019 This course is offered through Scholars Online, a non-profit organization supporting classical Christian education through online courses. Permission to copy course content (lessons and labs) for personal study is granted to students currently or formerly enrolled in the course through Scholars Online. Reproduction for any other purpose, without the express written consent of the author, is prohibited.