AP+Chem+Redox

Oxidation and Reduction

These two processes are linked. Another way to describe them is to call them "electron transfer."

You must be able to explain the role of the salt bridge. It completes the circuit by allowing charges to flow to the beakers. Sections 20.3 and 20.4 of Brown-LeMay give a good summary of these ideas, but don't forget to look at the Addison-Wesley book, chapter 23 -- pages 677 to 681 and 685 to 691 give clear descriptions of voltaic cells. || 20.13, 20.21, 20.23, 20.90, pages 822 and 826 || ||
 * = Concept ||= Summary with text references. || Problems in Brown-LeMay ||||= Worksheets from Mr. Robinson ||
 * OIL RIG || The first skill in the study of "redox" reactions is to remember the acronym OIL RIG. Oxidation is losing electrons, reduction is gaining electrons. ||  ||   ||   ||
 * Oxidation States || The second skill is assigning oxidation numbers. AP Chemistry students can learn this skill today. For a quick summary of the idea, read pages 128 to 130 in Brown-LeMay. Study the examples. A much more interesting presentation is on pages 645 to 659 of the Addison Wesley textbook. You should read both. || 4.39 and 4.41 on page 147. || [[file:AP worksheet VI-1 Oxidation States.pdf]] || [[file:AP worksheet VI-2 more Oxidation States.pdf]] ||
 * Balancing - Oxidation State || Use your knowledge of oxidation states when balancing Oxidation-Reduction Reaction equations. This skills is presented very nicely on pages 660 to 664 of the Addison-Wesley Textbook. Study the examples, then complete the two Balancing Equations worksheets shown at the right. || 20.3 and 20.5, page 821 || [[file:AP Worksheet VI-3 Balancing with ox states.pdf]] || [[file:AP Worksheet VI-4 balancing ox states.pdf]] ||
 * Balancing - Half Reactions || Redox equations can also be balanced by splitting them into half-reactions. This method is explained very clearly in both textbooks: pages 665-669 of Addison-Wesley and section 20.2 of Brown-LeMay (pages 779-784) In addition to the textbook problems, you can complete the worksheet shown at the right. || 20.7 and 20.9, page 821 and 20.87, page 826 || [[file:AP Worksheet VI-6 Half Reactions.pdf]] || [[file:AP worksheet VI-7 more half reactions.pdf]] ||
 * Voltaic Cells || Draw the parts of a voltaic cell and calculate the cell potential. A cell can be summarized as
 * two pieces of metal found inside...
 * two beakers, which contain solutions of the metal cations, and
 * two connections between the beakers (1) a wire connecting the pieces metal and (2) a salt bridge connecting the beakers.

|| ∆G = - n F E || 20.43, page 824 ||  ||   ||
 * Spontaneity || Try this simple formula, explained in section 20.5 of Brown-LeMay.
 * The Nernst Equation || Non-standard conditions influence the cell potential. The Nernst equation offers a simple way to calculate actual cell potential. The equilibrium constant can also be calculated from measured potentials. Read section 20.6 of Brown-LeMay to find out more. A very interesting essay about electrocardiography is found on page 804. || 20.47, 20.49, 20.51 and 20.57 on page 824. 20.93, page 827. ||  ||   ||
 * Electrolysis || Some non-spontaneous reactions are very important to humans. Read a summary of them in the Addison-Wesley book, section 23.3 (pages 692-697). More detail is given in section 20.9 of Brown-LeMay. Very important is the information on pages 816-819. You must be able to calculate the mass change in an electrode after a given current is applied for a given length of time. || 20.79, 20.81, and 20.85, page 826 ||  ||   ||

Some Oxidizing and Reducing Agents
 * = Oxidizing Agents ||||= Reducing Agents ||
 * = the agent ||= its product after it has oxidized other chemicals ||= the agent ||= its product after it has reduced other chemicals ||
 * O 2 (oxygen gas) || O 2- (oxide ion) || the alkali metals - Li, Na, K, Rb, Cs || ions of the alkali metals - Li +, Na + , K + , Rb + , Cs + ||
 * the halogens - F 2, Cl 2 , Br 2 , I 2 || the halide ions - F-, Cl-. Br-, I- || H 2 (hydrogen gas) || H + (hydrogen ion) ||
 * oxyanions (see below) ||  || C (graphite powder) || CO and CO 2 ||
 * NO 3 - (nitrate) || NO 2, a brown gas ||  ||   ||
 * ClO 3 - (chlorate) || ClO ||  ||   ||
 * MnO 4 - (permanganate) || Mn 3+, a pink ion ||  ||   ||
 * Cr 2 O 7 2- (dichromate) || Cr 3+, a green ion ||  ||   ||
 * solutions of the less reactive metals (Cu 2+, Ag + , and Au 3+ ) || the elements Cu, Ag, and Au ||  ||   ||