1. Define oxidation and reduction.
2. Compute the oxidation number of an atom of any element in a pure substance.
3. Distinguish between redox and nonredox reactions.
4. Identify the oxidizing and reducing agent in a redox reaction.
According to http://en.wikipedia.org/wiki/Oxidation_state:
"The oxidation state, often called the oxidation number, is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic."
Assigning the oxidation states of all components in a chemical reaction helps determine if oxidation and reduction are occurring. If oxidation occurs, another substance must be reducing. One analogy is that of a pitcher throwing a baseball, there must be a catcher for the baseball.
An equation that demonstrates a change in oxidation numbers shows both oxidation and reduction processes, typically shortened to the term "redox" .
By the way, a mnemonic used to remember the movement of electrons in redox is "LEO GER" where the loss of electrons is oxidation and the gain of electrons is reduction.
Another mnemonic is "OIL RIG" where oxidation is loss and reduction is gain.
Determining all of the oxidation states in a reaction helps in determining if redox is actually occurring.
Here is a video segment talking about these basics and providing a little history as well:
There are several lists of the Rules for Assigning Oxidation Numbers -- here's one:
Here are some more worksheets focusing on assigning oxidation numbers:
This worksheet also includes answers, and moves on into identifying the oxidizing and reducing agents:
In this video, all of the oxidation states are assigned and then what is oxidized and reduced and the corresponding agents can be identified:
Here is a PowerPoint presentation that is a helpful introductory lecture to Electrochemistry:
Here are some worksheets identifying what is oxidized/reduced/oxidizing agent/reducing agent:
This worksheet series does get into half-reactions as well -- that will be on the next post!
This worksheet also gets into half-reactions and balancing -- sorry!
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Each lab is presented with two possible report formats -- both labs use the same procedure page but each has a different conclusion page -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required. This gives the teacher the option of what type of report is desired!
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